Journal of Coastal Environment

Volume 1, Number 1, 2010

ISSN 2229-7839

JCE Journal of Coastal Environment

COES

Journal of Coastal Environment Journal of Coastal Environment (JCE) is published by the Centre for Ocean and Environmental Studies, New Delhi twice a year. The Journal promotes the study and analyses of scientific, economic and policy issues related to ecology of the oceans and coasts, as well as its impact on the land and the atmosphere. The emphasis is to involve a large community of scientists and scholars from India and abroad in developing a framework of discussion and debate on conservation and sustainable development.

Frequency

: Biannual

Editor-in-Chief

: S.Z. Qasim, Chairman, Centre for Ocean and Environmental Studies, New Delhi

Editor

: Kishore Kumar, Secretary & Consultant Centre for Ocean and Environmental Studies, New Delhi

Editorial Board K. Kathiresan

Rasik Ravindra

Professor, Centre of Advanced Study in Marine Biology, Annamalai University, Tamil Nadu

Director, National Centre for Antarctic & Ocean Research, Goa

M.C. Verma

Anil Chatterjee

IAS (Retd.) and former Member, Forest Advisory Committee (MoEF), New Delhi

Institute of Tropical Aquaculture University Malaysia Terengganu, Malaysia

B. Meenakumari

Sudhir K. Chopra

Deputy Director-General, Indian Council of Agricultural Research, New Delhi

Fellow, University of Cambridge at Rue de Neufchateau, Arlon, Belgium

Satish R. Shetye

Baishnab Charan Tripathy

Director National Institute of Oceanography, Goa

Professor, School of Life Sciences Jawaharlal Nehru University, New Delhi

Malti Goel

Vijay Sakhuja

Former Adviser, Ministry of Science & Technology, New Delhi

Director (Research), Indian Council of World Affairs, New Delhi

Amalesh Choudhury

Dinabandhu Sahoo

Founder & former Head, Department of Marine Science, University of Calcutta, Kolkata

Associate Professor, Department of Botany, University of Delhi, Delhi

© Journal of Coastal Environment (JCE). All rights reserved. No portion of material can be reproduced in part or full without the prior permission of the Editor. Note : The views expressed herein are the opinions of contributors and the Editor, and do not reflect the stated policies of the Centre for Ocean and Environmental Studies. Correspondence: All enquiries, editorial, business and any other, may be addressed to: The Editor, Journal of Coastal Environment (JCE), A-2, East of Kailash (Basement), New Delhi 110 065; Tel/Fax: 91-11-46078340; E-mail: [email protected]; [email protected]; Website: www.coes-india.org ISSN : 2229-7839

JCE Journal of Coastal Environment Volume 1, Number 1, 2010

Centre for Ocean and Environmental Studies A-2, East of Kailash (Basement), New Delhi 110 065; Tel/Fax: 91-11-46078340 E-mail: [email protected]; [email protected]; Website: www.coes-india.org

Editorial Our earlier publication, the Enviroscan newsletter started appearing in the year 2008, after the project “Scientific Investigation on Coastal and Island Ecosystems” was sanctioned by the Ministry of Earth Sciences. It continued to appear till the year 2009, with four issues of the newsletter published in the years 2008 and 2009 which were well received throughout the country. Since then, the Centre for Ocean and Environmental Studies (COES) has been registered, largely dealing with coastal and marine environment, with far reaching impacts on land and atmosphere. The coastal environment includes that area of the sea which begins from the land-sea interaction of the coast and extends into the sea, covering a large part of the continental shelf and most parts of the Exclusive Economic Zone (EEZ). Its area varies from region to region along both the east and west coasts. The coastal environment is very important because in this region lie most of our economic activities such as fishing, exploration and exploitation of mineral resources, ship breaking and repairs etc. The region is also very vulnerable to changes because it receives large quantities of both industrial and domestic wastes. It has two regions of special scientific interest. The inner region facing the sea is generally lined with mangrove plants, offering shelter to many animal communities and providing breeding ground to a large number of species. The other region facing the land includes sandy beaches. It gets exposed either partially or fully in accordance with the nature of tidal rhythm and is subjected to erosion by wave actions and forces of the tidal currents. The first paper of mine deals with some of the most important factors such as tidal changes, monsoon cycle, seasonal changes in temperature, and salinity and turbidity of water. The second paper by K. Kathiresan underlines the importance of mangrove forests in India. However, in spite of the fact that mangrove forests in the country have been fairly well protected during the last two decades, there is an urgent need of their conservation as they are largely responsible for the protection of coasts

from storms and cyclones. The third paper by Susanta Kumar Chakraborty describes the changes which the Midnapore Coast, West Bengal undergoes during the year and needs proper management. The next paper by Anil Chatterji and his colleagues gives an account of marine living resources and their use in traditional medicine. The paper by M.R. Boopendranath, et. al. describes the changes which the trawling operations are subjected to because of diurnal variation in trawl catches. The next paper by Abhijit Mitra, et. al. deals with the changes in salinity which the mangroves of Sundarbans area undergo, thus preventing the freshwater influx from the river Ganga to the central sector of Sundarbans. The seventh paper by P.J. Pradeep, et. al. gives an account of the induction of triploidy in the red hybrid tilapia by heat shock treatment. The last paper by Kishore Kumar gives the sources of health hazards due to air pollution in urban India, and also indicates control measures which are necessary.

S.Z. Qasim

This publication has been supported by the Ministry of Earth Sciences (MoES), Government of India.

Contents Some Environmental Factors affecting Coastal Waters S.Z. Qasim

1

Importance of Mangrove Forests of India K. Kathiresan

11

Coastal Environment of Midnapore, West Bengal: Potential Threats and Management Susanta K. Chakraborty

27

Marine Living Resources in the Practice of Traditional Medicine Anil Chatterji, Anuar bin Hassan, Amu Therwath and Faiza Shaharom

41

Energy Efficiency in Trawling Operations M.R. Boopendranath, V.C. George and M. Shahul Hameed

53

Impact of Salinity on Mangroves of Indian Sundarbans Abhijit Mitra, Ranju Chowdhury, Kasturi Sengupta and Kakoli Banerjee

71

Induction of Triploidy in Red Hybrid Tilapia by Heat Shock Treatment P.J. Pradeep, T.C. Srijaya, M.S. Shahreza, S. Mithun, H. Anuar and A. Chatterji

83

Air Pollution in Urban India: Sources, Health Hazards and Control Measures Kishore Kumar

95

Some Environmental Factors affecting Coastal Waters S.Z. Qasim* Abstract Unlike the open ocean, where environmental conditions largely remain stable, the coastal waters of India undergo constant changes during the year. The factors which affect the changes are tides whose amplitudes are large in northern part of India as compared to the southern region. However, there is no systematic decrease in the tidal range from north to south. Monsoon cycle is another factor which introduces drastic changes. Along the west coast, there is a heavy rainfall during south-west (SW) monsoon as compared to the east coast. Along the east coast the rainfall becomes pronounced only in West Bengal during SW monsoon; otherwise, along the rest of the eastern coast, the wet season lasts from September to December (south-east monsoon). The temperature of water at the surface varies from region to region within a range of 18°C to 30°C. Seasonal changes in temperature are quite pronounced, with a minimum during the monsoon months and a maximum during the premonsoon period. Salinity of water undergoes drastic changes during the year. Maximum salinity 32-34 ‰ is recorded during February to May and minimum approaching 3-4‰ during monsoon. Similarly, turbidity is highly regulated by the rainfall and land runoff. It is very high during the monsoon season and water gradually gets cleared during the dry months, recording maximum light penetration. Tidal flow also affects the clarity of water by stirring up sediments. Both incoming and outgoing tides are responsible for reducing the clarity of water. Large variations occur in dissolved oxygen (DO) during different seasons and from one region to the other. Marked reduction in DO has been noticed along the west coast, particularly in the vicinity of large towns because of waste disposal making drastic reduction in dissolved oxygen.

Introduction The sea can broadly be divided into two regions (1) open ocean and (2) coastal waters. The former largely remains stable except when * Former Secretary, Govt. of India and former Member (Science), Planning Commission, Govt. of India. Jour. Coast. Env., Vol. 1, No. 1, 2010

2

Journal of Coastal Environment

there is an influx of deep-sea currents or when upwelling occurs. During upwelling, the water from deeper regions is brought to the surface. Both currents and upwelling are short-lived seasonal phenomena. The coastal areas, on the other hand are constantly subjected to intermittent changes and the environmental factors which influence this region are as follows: Tidal rhythm Tides along most of the coastal regions, particularly in the northern parts of the country, are semidiurnal with two floods and two ebbs in 24 hours. However, along the southern coasts, there is a prominent component of mixed-semidiurnal rhythm. Thus, the tides at Cochin (Kochi) are mixed, predominantly semidiurnal type. The spring phase is dominated by semidiurnal whereas the neap phase is dominated by diurnal component (Srinivas et. al., 2003). Similar is the pattern at Tuticorin. Table 1 gives the ranges at 18 different places during the spring periods when the sun, earth and the moon are nearly along a line. Tidal range of a particular place largely seems to depend on the boundary conditions of the region. It is small in open ocean and gets amplified in bays, gulfs and closed areas. There is no systematic decrease of tidal range from north to south. For example, at Kandla on the west coast, the tidal range at spring is 6.32 m; a little further down south at Porbander it is 2.56; further south, it is 2.17 m at Veraval; and at Mumbai it is 4.1 m (see Table 1). The ranges in spring and neap tides are also variable. Thus, at Apollo Bundar (Mumbai), the ranges in spring and neap tides are 4.7 and 1.7 m respectively, whereas the corresponding levels of 2.5 and 1.5 m at the head of Mahim Creek have been reported. It decreases further in Karnataka and Goa with a range between 2 and 2.3 m; and in Kerala, the range of 1 m is recorded at Cochin and Thiruvananthapuram. On the east coast, a range of 5.04 m to 4.25 m has been recorded in the Hooghly region (Kolkata). This decreases progressively to 1.94 m and 1.06 m at Paradip and Chennai respectively. At Pamban Pass, the range remains only 0.64 m (Table 1). Monsoon cycle There are two monsoons in India the southwest (SW) and the northeast (NE). The former generally lasts for four months (June-

Some Environmental Factors affecting Coastal Waters

3

Table 1 Bhavnagar Kandla Diamond Harbour (Hooghly) Maypur (Hooghly) Sagar Island (Hooghly) Garden Reach (Kolkata) Mumbai Shorts Island Porbander

(m) 7.10 6.32 5.04 4.68 4.38 4.25 4.10 2.81 2.56

Mormugao Veraval Paradip Vishakhapatnam Kakinada Beypore Chennai Nagappattinum Pamban Pass

(m) 2.30 2.17 1.94 1.50 1.39 1.33 1.06 0.65 0.64

Spring tidal range at 18 different places along the coastline of India

September) when there is maximum rainfall along the west coast in coastal Maharashtra, Goa, Karnataka and Kerala. Coastal Maharashtra receives rainfall up to 1200 mm, except in the city of Mumbai where the average can go up to 1600 mm or even more. However, in several of these states, rainfall may continue with varying degrees during the rest of the year and the intense rainfall season may also show some change from year to year. Along the east coast, West Bengal (Kolkata) gets maximum rainfall during the SW monsoon, where the annual average may reach 1580 mm. In all other months of the year, little rainfall continues to occur. Orissa (Gopalpur) gets maximum rainfall from July to October; and from December to June, it has little rain. Similarly, Andhra Pradesh (Kakinada) gets maximum rainfall from July to October (1000 mm/yr) and Chennai in October and November. From September to November, cyclones are very frequent in the states of Orissa, Andhra Pradesh and Tamil Nadu which often get torrential rainfall associated with storms. Along the west coast of India, the SW monsoon is generally active from June to September at Bhavnagar, Mumbai, Karwar, Goa and Cochin. Minimum rainfall, 1.34 mm to 55.07 mm, may occur even after the main force of monsoon is over. In Thiruvananthapuram, there are practically no dry months during the year. Cochin normally has

4


three dry months (January-March; and from April premonsoon showers begin to appear. Karwar and Goa have 3-4 dry months and the average annual rainfall at these three places may reach 1800 to 2000 mm. Mumbai region has 4-5 dry months. In Bhavnagar (Gujarat), where the rainfall ranges 200 to 400 mm during the southwest monsoon, there is very little rainfall during the rest of the year. From the description given above, it can be concluded that there is no sharp distinction between the southwest and northeast monsoon. The latter is a transitional season when the withdrawal of SW monsoon occurs in the form of northeasterly winds, causing periodic showers associated with lightning and thunderstorm. Temperature regime Along the coast of West Bengal, the temperature of water during the year at the surface ranges between 18° and 33° C without any appreciable difference from one region to the other. Between surface and bottom, a maximum difference of only 1.5° C has been reported which is because the water remains well-mixed throughout the water column as the tidal range is large. In Orissa, the temperature of surface water follows the air temperature, and varies in the range of 23.5° to 33.2° C with minor differences from year to year. In Andhra Pradesh, the annual range in temperature from surface to bottom is about 4° C, depending upon the site of measurement. During the period of maximum freshwater discharge, in September and October, the temperature difference from surface to bottom is maximum. When the temperature is high during the dry season, the vertical gradient is small. In Tamil Nadu, the annual range in temperature is from 29.5° C in December to 33.5° C in August. Along the west coast (Kerala), the minimum temperature of 26° C was recorded in June / July, and the maximum of 35.5° C in April / May. In shallow areas, there is not much difference in temperature between surface and bottom. In Cochin Backwaters (Kerala), the minimum surface temperature of 28.4° C was recorded in July-August and maximum of 31.8° C in April-May. Practically throughout the year, the difference in temperature between the surface and bottom (9 m) is not more than 1 to 2° C except in July / August when the difference is 3 to 4° C.


5

In most of the Mumbai region, during the premonsoon season, there is little change in temperature between surface and bottom or from one station to the other as the water remains well mixed, ranging from 30.25° to 31.00o C. During the monsoon period, there is a decrease in o temperature, ranging from 26.50° to 28.50 C at the surface, and o between 27.0° to 28.0 C at the bottom. During the premonsoon months, o the range in temperature is 25.10° to 26.75 C (Varshney et al, 1984). Salinity cycle Of all the environmental factors, salinity is one factor which undergoes spectacular changes during the year in practically all along the coastal regions of India. The conditions along the coast become predominantly saline during the premonsoon season (February to May). However, with the onset of monsoon in June, salinity declines and most of the coastal regions remain freshwater-dominated until September. In West Bengal, large seasonal changes have been recorded o ranging from 30 /oo during February to May (premonsoon) to almost o freshwater conditions (1.6 /oo) during the SW monsoon. There is also a marked difference in salinity from one region to the other. The water in the upper regions largely remains as fresh water throughout the year. At the farthest point, beyond Kolkata, the salinity shows an o increase and records 2 /oo in May and June. The other very important feature to note in this region is that there is practically no difference in salinity between the surface and subsurface waters including the bottom except in the riverine part where the tidal influence is felt at the bottom and this extends up to 296 km upstream. A similar seasonal cycle has been reported from the Orissa Coast. o From January to May, the salinity values reach 30 to 34 /oo, thereafter declining suddenly from June and remaining close to 1 - 2 o/oo till September. Slightly higher salinity is recorded at the bottom. From October onwards, there is a sharp increase in salinity attaining almost marine conditions in subsequent months. Along the Andhra Coast, the annual variation in salinity is large. During the dry season (March to June), highest values are recorded and the lowest are during the monsoon season.

6


In the Coastal regions of Tamil Nadu, a sudden decline in salinity occurs from October to December during the NE monsoon, and low salinity remains for the said three months. Along the west coast of India, the salinity regime is somewhat similar, but larger variations are recorded during the SW monsoon. At o Thiruvananthapuram, during the SW monsoon (July - August), 0.12 /oo salinity is recorded at the surface and 0.3%o at the bottom. In February/March, salinity reaches 35.05 o/oo. Hardly any stratification is noticed in the water column. In the Cochin Backwaters, on the other hand, the salinity regime, as studied by Sankaranarayanan and Qasim (1969), is different. During the peak monsoon months (July/August), almost freshwater occupies the surface but the salinity at 4 m depth was 21o/oo during the same period and about 30 o/oo at the bottom (9 m). Thus, a clear stratification existed from June to November, keeping the salinity layers quite distinct. From December, the stratification was broken and homogenous conditions prevailed with salinity reaching o 35.5 /oo in April. o

In Karnataka, the recorded range in salinity was 1.33 /oo in August o (minimum) and 31.12 /oo in May (maximum). The Goa region behaves almost similar to the coast line of Kerala and Karnataka. From January to May, the coastal areas of Goa become seawater-dominated with salinity reaching 35 o/oo. In the Mumbai region, salinity is largely influenced by rainfall and land drainage during the monsoon season (June to September) and by the discharge of domestic wastewater generated by the city during the dry season. The wastewater released, either treated, partially-treated or untreated, into nearby creeks, bays, rivers or directly into the coastal 6 3 waters, amounts to 2.0x10 m /day. In addition to that, the nearshore regions receive effluents from 180 industrial units within the area of Municipal Corporation of Greater Bombay (MCGB). The Thane Creek, Bassein Creek, Mumbra Creek and Ulhas River receive 60 million litres per day (mld) of industrial wastewater. Monsoonal influence on salinity beyond 10 m depth of the open coast is small and only a marginal decrease is recorded during August, while a sharp decline in


o

7

o

salinity in inshore region from 30 /oo in June to 5 -15 /oo during August is quite common. In the coastal waters of Gujarat, intrusion of seawater occurs up to 44 km up-stream in early June when the river flow is minimum and up to 20 km in March when some riverine flow is maintained. Freshwater flow is maximum in August. Salinity of water varies widely between the ebb and the flood tides. The water remains well-mixed vertically with the absence of any stratification. Strong tidal currents exceeding 1m/sec sweep the shallow waters, making them vertically well-mixed except during short periods of tidal slack. Turbidity Like the temperature and salinity, the turbidity of the coastal waters is influenced by seasonal and climatic changes and the tidal flow. Highly turbid conditions prevail during the monsoon months, but during the postmonsoon period, the transparency of water increases but, from February onwards, stirring-up of sediments with a strong incoming tidal flow makes the water well-mixed and turbid. In Orissa, the transparency of water gets minimum during the monsoon season (July to October) and maximum from April to June. Turbidity is largely caused by silt-laden land runoff and clarity by the settlement of inert suspended matter and the intrusion of clearer seawater by the incoming tides. In the coastal waters of Andhra Pradesh, the total suspended matter (TSM) showed high concentrations ranging from 5 to 231 mg/l off Godavari. Tamil Nadu provides a highly turbid environment. Variation in attenuation coefficient (k) ranged from 1.4 (August), when the water was relatively clear, to a very high value in October 1978, when intensely turbid conditions prevailed. In 1978, the lowest value of 1.3 was recorded in June and the highest in December. In Kerala, maximum transparency of water, as indicated by Secchi Disk readings, was from February to May (premonsoon season). Light penetration was studied fairly intensively in Cochin Backwaters using different methods. A luxmeter with light intensity, of the range 0100,000 lux and sensitive to the entire visible range of sun and sky-

8


light, 300-750 mµ with a maximum response around 550 mµ, was lowered at various depths. For measuring high ranges of illumination, a special filter with a light absorption factor of 100 was used (for details see Qasim et. al., 1968). Euphotic zone is the depth of water where light can reach and photosynthesis takes place; and compensation depth is that depth where photosynthesis and respiration just balance each other, resulting in no production and no increase in organic matter over a day. At compensation depth, the illumination is reduced to about 1% of that at the surface. Dissolved oxygen Considerable variation in dissolved oxygen (DO) has been reported in coastal waters from season to season and from one region to the other in the same stretch of water. In coastal waters of West Bengal, although a sharp reduction in the clorinity occurs during monsoon months, the DO does not increase up to saturation value (Ghosh, et. al., 1991). The information available on the DO concentration along Andhra coast largely indicates the absence of organic pollution. There was a total absence of anoxic condition, and oxygen values reaching super saturation were recorded in many areas. At many places, along Tamil Nadu coast, nil value of DO was recorded because of intense pollution by sewage. Depletion of oxygen was recorded at all the stations worked in the rivers and estuaries. It was largely due to decomposition of organic matter present in the sewage by the heterotrophic bacteria using the available oxygen. On the West Coast, like temperature and salinity, the DO shows a marked seasonal change. At the surface, the values were subjected to little fluctuations, but at deeper layers a rapid decrease of DO was recorded during the monsoon months. Values as low as 1 to 2 ml/l were commonly observed near the bottom in the months of August, September and October. The vertical gradient of oxygen is an important feature of this coast during the monsoon season which


9

disappears when freshwater flow gets reduced and marine conditions begins to prevail from January to May. Such oxygen changes are associated with temperature and salinity. A similar situation has been reported from the Goa waters. In the coastal waters of Mumbai, because of the enormous quantities of sewage and domestic wastewater discharged into the bays and creeks or directly into the inshore water, the values of dissolved oxygen were generally low and irregular. In the Gujarat waters, rapid industrialisation has led to the emergence of many industrial towns near the rivers utilising freshwater according to their needs and conveniently disposing of wastewater either into the river or in the estuary and coastal waters, depending upon their location. The tidal range in the area during the spring flood is 5.5 m, and its influence varies considerably from monsoon to pre and postmonsoon periods. References Ghosh, S.K., De, T.K., Choudhury, A and Jena, T.K., 1991. Oxygen deficiency in Hooghly Estuary, east coast of India. Indian Journal of Marine Sciences, 20, pp. 216-217. Qasim, S.Z., Bhattathiri, P.M.A. and Abidi, S.A.H., 1968. Solar radiation and its penetration in a tropical estuary. Journal of Experimental Biology and Ecology, 2, pp.87-103. Srinivas, K., Revichandran, C., Maheswaran, P.A., Ashraf, T.T.M. and Murukesh, N., 2003. Prospects of tides in the Cochin estuarine system, Southwest coast of India. Indian Journal of Marine Sciences, 32, pp. 14-24. Varshney, P.K., Govindan, K. and Desai, B.N., 1984. Meiobenthos of polluted and unpolluted environment of Versova, Bombay. Mahasagar Bulletin of National Institute of Oceanography, 17, pp. 151-160. Zingde, M.D., 1999. Marine Pollution What are we heading for? In:

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Ocean Sciences: Trends and Future Directions. (ed.) B.L. Somayajulu. Indian National Science Academy & Academia Books International, New Delhi. pp. 229-245.

Importance of Mangrove Forests of India K. Kathiresan*

Abstract Mangrove forests in India are unique to have spectacular coverage both in wet and arid coasts of the country with a record of 4011 biological species including the globally threatened species. In spite of growing threats, the mangrove area has been well protected in the last two decades due to strong policy, legal framework and governance. There are 38 areas of mangrove forest in the country under implementation of management action plan, with 100% financial support by the Ministry of Environment and Forests, Government of India. There is a great need to monitor the mangrove and other coastal habitats for growing issues of climate change and sea level rise and for evolving strategies of coastal disaster management.

Introduction Mangrove forests are the coastal rainforests. These are among the world's most productive ecosystems, situated at the interface between land and sea in tropical and subtropical latitudes. The mangroves are the only tall tree forest on the Earth where land, freshwater and sea mix together. They are also known as 'tidal forests' or 'coastal woodlands', specially adapted to survive in harsh interface between land and sea and in conditions of high salinity, extreme tides, strong winds, high temperatures, low oxygen and muddy soil. They are gifted with arching roots, breathing roots, salt-vomiting leaves, mud-dancing fishes and breath-taking beauty. Biomass in mangroves is greater than any other aquatic systems. The mangrove forests are of great environmental significance and socioeconomic value: (i) protecting shores from wind, waves and water * Professor, Centre of Advanced Study in Marine Biology, Annamalai University, Parangipettai, Tamil Nadu.

Jour. Coast. Env., Vol. 1, No. 1, 2010

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currents, (ii) preventing soil erosion and siltation, (iii) protecting coral reefs, seagrass beds and shipping lanes, (iv) supplying wood and other forest products, (v) providing habitats and nutrients for a variety of organisms, and (vi) supporting coastal fisheries and livelihoods. Their monetary value is about 0.5 million rupees per hectare per year and this is greater than that of coral reefs, continental shelves and/or the open sea (Kathiresan and Bingham, 2001; Kathiresan and Qasim, 2005). In south India, a mangrove species 'Thillai' is worshipped as a 'temple tree' at Chidambaram. Global mangroves have an estimated cover of 15.2 million hectares (FAO, 2007), of which about 90% are present in developing countries, but are nearing extinction in 26 countries. Their long term survival is at great risk due to fragmentation of the mangroves, with the ecosystem services offered by them in danger of being totally lost within 100 years (Duke et. al., 2007). The mangrove habitats continued to disappear globally at a rate of 0.66% per year during the period of 2000-2005 (FAO, 2007). It is in this context, flora and fauna of the mangrove ecosystems of India are mostly at threat (Rao et. al., 1998). The actual number of flora that exists in different regions of India is not fully known due to scattered data, the absence of their comprehensive compilation and lack of extensive field surveys. Mangrove forest cover in India Mangroves in India are spread over an area of 4,639 sq. km, occupying only 0.14% of the geographical area of the country but represent about 3 % of the global and 8% of Asian mangrove coverage (SFR, 2009; FAO, 2007). About 60% of the Indian mangroves are lying on the east coast along the Bay of Bengal, 27% on the west coast lined with the Arabian Sea, and 13% on Andaman and Nicobar Islands. This differential distribution can be attributed to two reasons: (i) the east coast has long estuaries with larger deltas and runoffs due to the presence of mighty rivers, whereas the west coast has funnel-shaped estuaries with an absence of delta formation; and (ii) the east coast has a smooth slope providing larger areas for mangrove colonisation, whereas the west coast has a steep and vertical slope. Most spectacular mangroves are found in Sundarbans in West Bengal with the maximum of mangrove cover (46.39%) in the country, followed by Gujarat (22.55%) and

Importance of Mangrove Forests of India

13

Andaman & Nicobar Islands (13.26%). In the Andaman and Nicobar Islands, many tidal estuaries, small rivers, neritic islets and lagoons support rich mangrove flora. Mangrove forest cover in India is classified as very dense, moderately dense and open types based on percentage of its green cover; i.e. >70%, 40-70% and 10-40% respectively. They are very dense in 1,405 sq. km (30.29%), moderate in 1,659 sq. km (35.76%) and sparse in 1,575 sq. km (33.95%). The sparse areas require special attention for increasing the green cover of those areas. Much more area, having the potential for mangrove afforestation is to be identified and promoted for management.

State/UT

Table 1 Year of assessment

Change of forest cover

2005

2003-2005

2007

Andhra Pradesh Goa Gujarat Karnataka Kerala Maharashtra Orissa Tamil Nadu West Bengal Andaman and Daman and Diu Pondicherry

329 16 936 3 8 158 203 35 2118 637 1 1

353 17 1046 3 5 186 221 39 2152 615 1 1

0 0 20 0 0 0 0 0 -2 -21 0 0

Total

4445

4639

-3

2005-2007 -1 1 55 0 0 0 4 3 16 -20 0 0 58 2

State-wise cover of mangrove forests of India in km Source: Food and Agricultural Organisation (UN), 2007

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Trends of change in forest cover: Mangrove cover showed a net 2 increase of 58 km within two years between the years 2005 and 2007. This increase was mainly because of Gujarat which showed an increase 2 of 55 km in mangrove cover due to plantations and protection. There 2 2 was also an increase of 16 km in mangrove cover of West Bengal, 4 km 2 in Orissa and 3 km in Tamil Nadu (Table 1; SFR, 2009). However, there was a loss of 20 km2 in Andaman and Nicobar Islands, due to the effect of Tsunami in December 2004. This loss was reduced by 1 km2 in the year 2005 due to natural regeneration of mangroves. In general, the mangroves in India have become fairly well protected in the last two decades in spite of growing threats by climate change and man, mainly due to the efforts of Government of India. There are 38 mangrove areas in the country under active implantation of management action plan with 100% financial support by the Ministry of Environment and Forests, Government of India. Mangroves in India are protected through a range of regulatory measures such as Coastal Regulation Zone Notification, 1991; Environmental Impact Assessment studies under EIA Notification, 1994; Mangroves located within the notified forest areas also covered under the Indian Forest Act, 1927 and Forest Conservation Act, 1980. Biodiversity of mangrove forests Mangroves are rich in genetic diversity due to the occurrence of both aquatic and terrestrial species and their adaptability to a wide range of salinities, tidal amplitudes, winds, temperatures, and even muddy and anaerobic soil conditions. Their habitats are as diversified as core forests, litter-forest floors, mudflats, water bodies (rivers, bays, intertidal creeks, channels and backwaters), adjacent coral reefs and seagrass ecosystems (wherever they occur). Indian mangroves are diverse with 125 species, comprising of 39 mangroves and 86 mangrove associates. About 56% of the world's mangrove species occur in India, with mangrove associates having 30 tree species, 24 shrubs, 18 herbs, six climbers, four grasses and four epiphytes. Their species diversity is highest in Orissa (101 spp.) followed by West Bengal (92 spp.), Andaman and Nicobar Islands (91 spp.) and lowest in Gujarat (40 spp.). One among the two genetic paradises in the world is in India at Bhitarkanika of Orissa State, which is not yet explored fully for their


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genetic diversity. In fact, there is one island namely Kalibhanj dia, adjacent to Dhamra Port in Bhitarkanika, having a total of 101 plant species (31 true mangroves +70 mangrove associates) which is 81% of mangrove species in India in a small area. There are several such areas with rich taxonomic diversity which should be identified and managed as mangrove germplasm preservation centres. Table 2 Sl. No.

Groups

No. of Species

Flora 1 Mangroves 2 Mangrove associates* 3 Sea grasses 4 Marine algae** 5 Bacteria 6 Fungi 7 Actinomycetes 8 Lichens Fauna 9 Prawns and lobsters 10 Crabs 11 Insects 12 Molluscs 13 Other invertebrates 14 Fish parasites 15 Fin fish 16 Amphibians 17 Reptiles 18 Birds Total number of species

39 86 11 557 69 103 23 32 55 138 707 305 745 7 543 13 84 426 4011

*Plants that occur in the coastal environment and are also found within mangroves **Include phytoplankton and seaweeds

Total number of species of flora and fauna reported in mangrove ecosystems of India Source: Kathiresan and Qasim, 2005

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Mangrove forest ecosystems in India support diverse groups of organisms with a total of 4011 that include 920 floral species and 3091 faunal species (Kathiresan, 2000; Table 2); perhaps the largest biodiversity record in the world mangrove ecosystems. No other country in the world has recorded so many species to be present in the mangrove ecosystem with the faunal species component about 3.5 times greater than the floral component of the mangrove ecosystem. The dense mangrove forests in Sundarbans is unique to have globally threatened species such as Royal Bengal tiger, sea turtles, fishing cat, estuarine crocodile, the Gangetic dolphin and river terrapin. Some wildlife species of mangrove ecosystem, like water monitor lizard and wild boar, are yet to be studied for biology. Mangroves of restricted distribution Our field study reveals that 11 mangrove species and 8 associates are restricted in distribution. Acanthus ebracteatus is known to occur only in the Andaman Islands of India. Xylocarpus species are reportedly restricted to Andaman and Nicobar Islands, Sundarbans, Mahanadi delta, Andhra Pradesh and Pichavaram (Banerjee, et. al., 1989; 1998; Naskar and Mandal, 1999; Dagar, et. al., 1991; Kathiresan and Ravikumar, 1993). However, two species, of Xylocarpus, X. mekongensis and X. moluccensis, are seen along the Konkan coast in Achra mangroves on the west coast. Brownlowia tersa which was reportedly restricted from Sundarbans southwards up to Mahanadi delta does occur at Gadapanda in east Godavari District. Some 80 years earlier, this species reportedly grew abundantly nearer to large creeks of Middle Andamans and Dhanikhari creek, but rarely observed there now (Hajra, et. al., 1999). Scyphiphora hydrophylacea is reported from Krishna and Godavari estuaries, Sundarbans, Andaman and Nicobar Islands (Banerjee, et. al., 1989; Naskar and Mandal, 1999). We have located the species in small pockets at Godavari Delta as well as in the adjoining areas of Krishnapatnam harbour. In Sundarbans, due to reduction in freshwater inputs, the freshwater loving species like Nypa fruticans and Heritiera fomes have reduced population density. Even species of Xylocarpus are becoming rare in Sundarbans due to over-exploitation (Naskar and Mandal, 1999).


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Endemic species of mangroves in India To the best of our knowledge, only one mangrove species is known to be endemic one to India, i.e. Rhizophora x annamalayana Kathir., a natural hybrid derived between two species of Rhizophora (R. apiculata and R. mucronata), occurring in Pichavaram of Tamil Nadu (Kathiresan, 1995, 1999). It is confirmed as a new species by using DNA markers (Parani, et .al., 1997). We have recorded only 171 individual trees of the species with a height ranging from 9 to 12 metres, with broad, dark green leaves and robust aerial stilt roots, mostly located between its parental species. This critically endangered hybrid is included in the global list of mangrove species (FAO, 2007). Another endemic species is Heritiera kanikensis that reportedly exists only in Bhitarkanika of Orissa (Majumdar and Banerjee, 1985). Our field visits to the study site at Bhitarkanika and reexamination of both the field specimen and herbarium specimen at Botanical Survey of India, Kolkata, reveal that the species is only Heritiera fomes, not a new one. It is further corroborated by the local people of Bhitarkanika mangrove forest who are also of the opinion that there are no new species like Heritiera kanikensis, but are only two species namely Heritiera fomes and H. littoralis. Mangrove species under dispute Mangrove taxonomy needs further studies in the field and laboratory, and at molecular levels (using DNA sequence data) for resolving the disputes in identification of species. Rigorous systematic studies are required through assessments of morphological, chemical and genetic variations among mangrove species to develop phylogenetic understanding of individual taxa across their distributional ranges (Duke, 2006). Many specimens identified and indexed as Acanthus ilicifolius in Indian herbaria are Acanthus ebracteatus, as argued by Remadevi and Binoj Kumar (2000) who observed the presence of this species in marshy areas of Aroor in Alappuzha District of Kerala. However, this identification is questioned by Anupama and Sivadasan (2004). Ecological varieties in Avicennia marina and Ceriops tagal need to be recognised. For example, four species of Avicennia are locally identified in the Gulf of Kachchh of Gujarat, but it is difficult to relate their local names with botanical names (Singh, 2000). There are several natural hybrids, but their parental species are not clearly understood, especially for the species of Rhizophora.

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Globally threatened mangroves in India Mangroves habitat loss has put at least 40% of the animal species that are restricted to mangrove habitat at an elevated risk of extinction under the International Union for Conservation of Nature (IUCN) categories and criteria. However, none of the global mangrove plant species have been entered in the IUCN Red List. Very recently, assessments of mangrove species were made by 24 global mangrove workers including myself, in two workshops, one in 2007 in Dominica and the other in 2008 in the Philippines. The results published in PLoS ONE reveal that 11 of the 70 mangrove species in the world (16%) are at an elevated threat of extinction (Polidoro, et. al., 2010), of which only two species, namely Sonneratia griffithii (critically endangered), and Heritiera fomes (endangered) exist in India. All other mangrove species in India are in the IUCN category of least concern and only one species, Brownlowia tersa is in the category of near threatened species (Kathiresan, 2010). Threats and management prescriptions Mangroves and associates are likely to become vulnerable in near future due to both man-made and natural threats. More widely distributed species such as Aegiceras corniculatum, Acanthus ilicifolius, Avicennia marina, A. officinalis and Excoecaria agallocha, have great ecological amplitude and remarkable ability of vegetative regeneration. Even these species may decline in near future due to increasing human pressure and climate change. Habitat loss and fragmentation Species with limited salinity tolerance will reduce in populations, interbreeding among those limited populations may reduce genetic vigour and resilience to stress that may likely place the populations at greater risk of local extinction (Duke, 2006). Therefore, it is necessary to protect larger mangrove areas or to improve the extent of mangroves areas, and/or connecting a series of smaller areas. Reduction of ecosystem health Indian mangroves are generally not very healthy, and dense mangrove forests are absent except in three regions, namely Sundarbans (42% dense), Andaman & Nicobar Islands (39%) and Maharashtra (7%). Sparse


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mangrove forests range from 15 to 96% in different states of the country. Their poor health condition makes the population with reduced genetic vigour, resilience and ability to respond to changing environmental conditions. Also, the poor health of plant will lead to loss of reproductive potential and regenerative capability. 'Top dying' disease of mangrove trees is an example leading to drying and death of leaves and branches from top to bottom with reduced wood productivity. It is, therefore, necessary to find out the factors responsible for poor health, and then overcome them for converting the population healthy. Poor natural regeneration Propagules are abundantly produced in most of the mangrove forests, but their dispersal, survival and establishment are of serious concern. Dispersal of the propagules is restricted by both land barriers blocking current flow and wide expanses of water (Duke, 2006). Therefore, it is necessary to assess natural regeneration for its constraints like terms of hydrological changes from upstream to downstream areas, and to implement correction measures for facilitating the dispersal and establishment of mangrove propagules. Effect of climatic change A growing threat to global mangrove ecosystem is the climate change, associated with increasing temperature, changing hydrologic regimes, rising sea level, and increasing magnitude and frequency of tropical storms and natural calamities like Tsunami. To these changes, mangroves are likely to be one of the first ecosystems to be affected, especially in lowlying areas, because of their location at the interface between land and sea. In Indian Sundarbans, two islands, namely Suparibhanga and Lohacharra have recently submerged and a dozen other islands on the western end of the inner estuary delta are under the threat of submergence (The Daily Star, December 22, 2006). As the sea level rises, mangroves would tend to shift landward. Human encroachment at the landward boundary, however, makes this impossible. Consequently, the width of mangrove systems would be likely to decrease with the sea level rise. This habitat loss might cause a gradual depletion of the rich biodiversity of mangrove forest flora. However, a few genetically superior plant species, which can overcome any climatic change, do exist in the mangrove habitats, which have to be

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identified, propagated and introduced in the areas that are vulnerable to natural calamities and sea level rise. Further research is recommended to record plant species with details of their flowering, germination, propagation, growth as related to changing climatic (Kathiresan and Faisal, 2006) to determine the climate change-induced effects on mangrove species. Potential impacts of climate change Effect of changes in temperature: Mangroves are not expected to be adversely affected by the projected increases in sea temperature of 26°C by 2100. However, temperature greater than 35°C may alter root structure and seedling establishment, and the photosynthesis may be affected at 40°C. At the same time, an increased sediment temperature may increase growth rates of bacteria which are likely to increase the recycling and regeneration of nutrients. Effect of changes in carbon dioxide: Increase in CO2 is also not likely to cause any increase in mangrove canopy photosynthesis, but it may increase the rate of net photosynthesis and growth rate of mangroves when the soil salinity is low. The advantage is the water use efficiency by mangroves by reducing the water loss via transpiration; this advantage will be lost when the salinity increases in arid regions. One indirect effect of the increase of temperature and CO2 is the degradation of coral reefs due to mass bleaching and impaired growth. As a result, protection function of coral reefs from wave action will be lost, thereby affecting the mangroves. The mangrove wetlands are efficient habitats for carbon burial, about 2.4fold as high as saltmarshes and 5.2-fold as high as seagrasses. The mangroves sequester as much as 50 times the amount of carbon in their sediment per hectare of tropical forest. More studies are required on the role of microbes in carbon sequestration of the coastal vegetated habitats. In this regard, photosynthetic anaerobic bacteria in the coastal wetlands deserve a serious research attention. Effect of change in precipitation: Precipitation may increase by 25% by 2050 due to global warming. This may result in increase of mangrove area, as well as growth rates and diversity of mangrove zones. However, the precipitation varies unevenly at regional scales either increase or decrease.


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Effect of changes in hurricanes and storms: There may be 5-10% increase in intensity of storms by 2050. This will affect mangrove health and species composition due to changes in salinity, recruitment, inundation and changes in wetland sediment budget. Storm surges can also flood the mangroves and may destroy them in combination with sea-level rise. Avicennia species are more vulnerable than Rhizophora species, mainly due to stilt roots of the latter which stands above sea-level than the pneumatophores of the former which remain mostly submerged. Moreover, stilt roots trap sediments and facilitate peat accumulation in the mangrove areas. Effect of changes in Sea level rise: Sea level rise is the greatest climate change that the mangroves face. They can adapt to it if it occurs slowly enough, if the rate of sediment accretion is sufficient to keep with sea level rise and if adequate expansion space exists without any interference caused by infrastructure (e.g., roads, agricultural fields, dikes, urbanisation, seawalls and shipping channels) and topography (e.g., steep slopes). Tidal range and sediment supply are two critical indicators of mangroves, response to sea level rise. The mangroves with macro-tidal and sediment rich areas are able to survive sea level rise than those with micro-tidal and sediment starved areas. The most vulnerable mangroves to sea-level change are located in areas with small islands, lack of rivers, carbonate settings, tectonic movements, groundwater extraction, underground mining, micro-tidal and sedimentstarved areas, and with coastal development and steep topography. The least vulnerable mangroves are situated in riverine areas, macro-tidal and sediment rich areas, and dense mangrove forests. Strategies to mitigate climate change effects 1.

Protection of species and habitats: To mitigate the risk of losing mangroves to sea-level rise, it is necessary to identify and protect critical areas, species and also sources of propagules to ensure replenishment following disasters.

2.

Management of man-made pressure: Mangroves have to be protected from anthropogenic pressures by implementation of management practices through provision of sustainable and alternative livelihood to the mangrove-dependent people.

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3.

Establishment of green belts and buffer zones: It is necessary to raise green belts along open coast, river banks/lagoons and islands/creeks/channels with a mangrove greenbelt width of 100 -500 m, 30-50 m and 10 m respectively for coastal protection from erosion. It is also necessary to maintain buffer zones bordering the seaward and landward margins of protected mangroves to provide a transition between human inhabitation and natural environment either landward or seaward.

4.

Restoration of degraded areas: This can be done by (i) hydrological manipulation through construction of creeks, thereby flushing the degraded areas with tidal waters, (ii) community participation, and (iii) integrated farming practices.

5.

Connectivity of mangroves with other systems: This can be done by ensuring the linkage between mangroves and sources of freshwater and sediments, and between mangroves and their associated habitats like coral reefs and seagrasses.

6.

Baseline data development: It is required to establish baseline data on forestry structure, species richness, abundance and diversity of flora and fauna, primary production nutrient and hydrological aspects for monitoring the response of mangroves to climate change.

7.

Establishment of partnerships at local, regional and global scales

Conclusions Mangroves are uniquely adapted coastal plants of great ecological and economic significance. They act as a natural barrier against severe storms, and they significantly reduce deaths, livestock loss and property damage. In October 1999, Orissa was battered by the super cyclone that killed almost 10,000 people and caused a massive loss of livestock and property. The loss of human life caused by the storm was directly linked to the removal of the natural defence provided by mangroves. Similarly, the role th of mangroves in coastal protection against the 26 December 2004 Tsunami was remarkable. Mangrove and casuarinas plantations reduced Tsunami-induced waves and protected shorelines, human lives and properties against damage in southeast Tamil Nadu (Kathiresan and Rajendran, 2005; Danielsen, et. al., 2005). Mangroves also enhance fisheries and forestry production, and these benefits are not possible with


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concrete coastal protection structures. Moreover, the establishment and maintenance of coastal vegetation incur only low cost as compared to concrete structures used for coastal protection. Besides providing coastal protection, they are also known for ecological and livelihood benefits, as well as efficient carbon sequestration. Therefore, raising the coastal mangroves as a bio-shield is a priority task. Bioprospecting of mangrove ecosystems, in search of valuable products and genes, is of growing interest in India. They are the promising source of valuable products such as black tea-like beverage, mosquito repellents, enzymes, pigments, nanoparticles, microbial bio-fertilisers, bio-feed, single cell proteins, and medicines to cure dreadful human diseases like AIDS and cancer. The M.S. Swaminathan Research Foundation has isolated salt-tolerant genes from the mangrove species Avicennia marina, and introduced it into a paddy crop (Pusa Basmati and IR64) via Agrobacterium. The salt tolerant paddy variety is under experimental trial. With the increasing seawater intrusion due to coastal climate change, it is necessary to find out high salt tolerant genotypes of mangroves. This will have a bearing on resilience and recovery of mangrove species under changing coastal climatic conditions. With the increasing seawater intrusion due to coastal climate change, it is necessary to record plant species with details of their flowering, germination, propagation and growth, as well as the behaviour of animals to determine the climate change-induced effects on the biological species of mangrove ecosystems. The mangrove habitat in India is proved efficient in carbon sequestration, 2.4-fold as high as saltmarshes, 5.2-fold as high as seagrasses and 50 times as high as tropical forests. Occupying just 0.29% of Indian coastal area, the mangroves are contributing to 2.2% carbon burial. Therefore, mangrove restoration can be a novel countermeasure to global warming. Mangroves in India are likely to absorb, and respond to, change and disturbance of climate change. This calls for intensive attention on managing the mangroves for resilience to climate change through implementation of adaptation strategy such as (i) to identify salinity and flood tolerant species and to plant them in the sites which are vulnerable to salinity and sea level rise , (ii) to record the plant species with details

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about their flowering, fruiting, germination, propagation, growth and evaporation demand as related to climate change, (iii) enhancing the density of mangrove stand, diversifying the mangroves using most adaptable species, amendment of substrates for favourable colonisation of mangroves. It is necessary to collate comprehensive species-specific information for mangroves of India, in absence of which it will be difficult to identify and implement conservation priorities. It is a matter of urgency to protect and propagate the two globally threatened species, Sonneratia griffithii and Heritiera fomes which are growing in India, in order to increase their population size in their habitats. Research intervention is required to overcome the problem of low seed viability in those species, as well on the natural hybrids that occur in the families of Rhizophoraceae and Sonneratiaceae, and also on the ecological varieties of Avicennia marina and Ceriops tagal. Further studies are required on the discontinuous distribution and occurrence of mangroves along the coastal India. Acknowledgments The author is thankful to authorities of Annamalai University for providing facilities, and to the Ministry of Environment & Forests, Govt. of India for providing financial support. References Anupama, C. and Sivadasan, M. 2004. Mangroves of Kerala, India. Rheedea, 14, 9-46. Banerjee, L. K., Ghosh, D. and Sastry, A. R. K. 1998. Mangroves, Associates and Salt Marshes of the Godavari and Krishna Delta. Botanical Survey of India, Calcutta, pp. 1-128. Banerjee, L.K., Sastry, A.R.K. and Nayar, M.P. 1989. Mangroves in India Identification manual. Botanical Survey of India, Calcutta, pp. 1-102. Dagar, J.C., Mongia, A.D. and Bandyopadhyay, A.K. 1991. Mangroves of Andaman and Nicobar Islands. Oxford & IBH, New Delhi, India, 166 pp. Danielsen, F., Sorensen, M.K., Olwing, M.F., Selvam, V., Parish, F., Burgess, N.D., et. al., 2005. The Asian tsunami: A protective role for coastal vegetation. Science, 310, p. 643.


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Duke, N.C. 2006. Mangrove taxonomy, biogeography and evolution: in International Conference and Exhibition on Mangroves of Indian and Western Pacific Oceans, ICEMAN, Kuala Lumpur, Malaysia. Duke, N.C., Meynecket, O.J. Dittmann, S., et. al., 2007. A world without mangroves? (Letters). www.sciencemag.org. p.41. FAO, 2007. The World's mangroves 1980-2005, Forestry Paper No. 153. 77 pp. Hajra, P.K., Rao, P.S.N. and Mudgal, V. 1999. Flora of Andaman and Nicobar Islands. Botanical survey of India, Calcutta, 1. Kathiresan, K. l995. Rhizophora annamalayana: A new species of mangrove. Environment and Ecology, 13 (1), pp. 240-241. Kathiresan, K. l999. Rhizophora annamalayana Kathir. (Rhizophoraceae), a new nothospecies from Pichavaram mangrove forest in southeastern peninsular India. Environment and Ecology, 17 (2), pp. 500-501. Kathiresan, K. 2000. A review of studies on Pichavaram mangroves, southeast coast of India, Hydrobiologia, 430 (1), pp. 185-205. Kathiresan, K. 2002. Why are mangroves degrading? Current Science, 83, pp. 1246-1249. Kathiresan, K. 2010. Globally threatened mangrove species in India. Current Science, 98 (12), p. 1551. Kathiresan, K. and Bingham, B.L. 2001. Biology of mangroves and mangrove ecosystems. Advances in Marine Biology, 40, pp. 81-251. Kathiresan, K. and Faisal A. M. 2006. Managing Sundarbans for uncertainty and sustainability. In International Conference and Exhibition on Mangroves of Indian and Western Pacific Oceans, ICEMAN, Kuala Lumpur, Malaysia, pp.1-31. Kathiresan, K. and Qasim, S.Z. 2005. Biodiversity of Mangrove Ecosystems. Hindustan Publishing Corporation, New Delhi, 251 pp.

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Kathiresan, K. and Ravikumar, S. 1993. Two endangered species of mangroves in Pichavaram. Indian Forester, 119 (9), pp. 773-776. Kathiresan, K., and Rajendran, N. 2005. Coastal mangrove forests mitigated tsunami. Estuarine, Coastal Shelf Sciences, 65, pp. 601-606. Majumdar, N.C and Banerjee, L. K. 1985. Bulletin of Botanical Survey of India, 27 (1-4), pp. 150-151. Naskar, K. R. and Mandal, R.N. 1999. Ecology and Biodiversity of Indian Mangroves, Daya Publishing House, New Delhi, 1 & 2, 53 pp. Parani, M., Rao, C.S., Mathan, N., Anuratha C.S., Narayanan, K. K. and Parida, A. 1997. Molecular phylogeny of mangroves. III. Parentage analysis of a Rhizophora hybrid using random amplified polymorphic DNA and restriction fragment length polymorphism markers. Aquatic Botany, 58, pp. 165-172. Polidoro, B.A., Carpenter, K.E., Collins, L., Duke, N.C., Ellison, A.M., Ellison, J.C., Farnsworth, E.J., Fernando, E.S., Kathiresan, K., Koedam, N.E., Livingstone, S.R., Miyagi, T., Moore, G.E., Vien Ngoc Nam, Ong, J. E., Primavera, J.H., Salmo, S.G., III, Sanciangco, J.C., Sukardjo, S., Wang Y. and Yong, J.W.H. 2010. The loss of species: Mangrove extinction risk and geographic areas of global concern. PLoS ONE, 5 (4), pp. 1-10. Rao, A. T., Molur, S. and Walker, S. 1998. Report of the workshop on “Conservation Assessment and Management Plan for Mangroves of India, Zoo Outreach Organisation, Coimbatore, India, pp. 1-106. Remadevi, S. and Binoj Kumar, M.S. 2000. Journal of Econ. Taxon. Bot., 24 (1), pp. 241- 242. Singh, H.S. 2000. Mangroves in Gujarat: Current status and strategy for conservation, GEER Foundation, Gandhinagar, Gujarat, India, pp. 1-128. State Forest report- 2009, Forest Survey of India, Dehradun.

Coastal Environment of Midnapore, West Bengal: Potential Threats and Management Susanta Kumar Chakraborty* Abstract The paper deals with the Integrated Coastal Zone Management (ICZM) of the Midnapore Coast, West Bengal. It is suggested that management studies should include baseline information related to rainfall, runoff, tidal rhythm, currents and waves with their related aspects. This information is important to develop proper coastal protection measures. Beaches and shoreline should not be considered simply as an object of beauty for recreation only and holiday-making. These are assets of great economical value and need measures to be devised for their protection. It is necessary to make a study of flora and fauna with their distribution in relation to prevailing economic conditions so that conservation measures could be devised. Existing mangroves and associated coastal vegetation should be fully protected by adopting suitable means. Tourism should be encouraged according to the nature of the environment. To enforce coastal regulatory laws in relation to the various activities related to coastal management. These laws have been formulated in relation to coastal protection.

Introduction Among all the 9 maritime states of India which have an impressive coastline, the total of them amounts to 7500 km (approximately). The state of West Bengal (W. B.) commands a significant geographical location harbouring the mighty Ganga estuary (Hoogly-Matlah estuarine complex), shared with the neighbouring country Bangladesh. Historically and geographically the coastal Midnapore is a contiguous part of deltaic Sundarbans of global importance, limiting the Hoogli estuary on the western front. The coastal area of W.B. extends over * Professor, Department of Zoology, Vidyasagar University, Midnapore, West Bengal. Jour. Coast. Env., Vol. 1, No. 1, 2010

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0.82 million hactre and extends along 220 km of coastal line. Of the two coastal districts of W.B., the undivided Midnapore district is characterised by sand dunes, long shore currents, high salinity, low turbidity and low vegetative coverage in comparison to its counterpart, (the South 24 Parganas District) supported by Sundarban Mangrove Ecosystem (Annon, 2005, Paul, 2002). The Midnapore coast (60 km) covers 27% of the W.B. coastal tract extending along the west bank of Hoogli Estuary from New Digha at the extreme south west point of the Midnapore district and then curving around Junput, Dadanpatrabarh, Khejuri and Haldia on the east to further northeast up to Tamluk (erstwhile Tamralipta) or even Kolaghat on the bank of Rupnarayan (Fig. 1). Biodiversity of this coastal environment, i.e. floral and faunal diversities are in tune with habitat diversity in this short stretch coastal zone and represents striking features with the regard to ecosystem functioning, commercial bioresource production, coastal zone management and promotion of ecotourism. Biodiversity is dynamic at all three levels, the genes, species and habitats and changes over time in response to natural and human- induced selection pressures. Diversity of habitats in terms of changing physical, Fig. 1

Map of Coast Midnapore, West Bengal

Coastal Environment of Midnapore : Potential Threats and Management

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chemical and geomorphological parameters imparts impact on genetic composition which leads to the changes of biotic assemblages spatially ad temporally. Habitat diversity of Midnapore coast: The Midnapore coastal tract (longitudinal extension 87°20'E to 88°5'E and latitudinal extension 21°30'N to 22°2'N) in between Hoogli and Subarnarekha estuarine confluence with the Bay of Bengal, although very short in length, it displays unique habitat diversities in respect to vegetation composition, occurrence of dunes, mudflats, sandflats and other ecological parameters like variation of salinity, temperature, texture of sediments etc. Besides, this coastal tract can be divided into two distinct zones based on the continuous erosion and accretion processes. Different habitats having contrasting ecological features are as follows: S-I. Talsari: This site is located at the confluence of Subarnarekha estuary with the sea. The Subarnarekha estuarine delta is the westernmost unit of the topographic expression in the present coastal plain. A degraded tract of mangrove swamp is still in existence around the estuarine link of Talsari tidal and intertidal flats. S-II. Digha (Old and New): The history of modern Digha is not very th old. In 18 century, the Digha village under Birkul Parganas under the British Rule was a health resort for the British in India and was considered as the most popular weekend beach resort in West Bengal. In the present day, over 40 lakhs tourists visit Digha every Year. S-III. Shankarpur: Shankarpur, a small village located 180 km. away from Kolkata and 16 Km West from Digha in the coast of Bay of Bengal. Shankarpur is a well known fishing harbour and also a tourist spot of West Bengal. This fishing harbour has a capacity of providing facilities for to and fro movement of more than 150 mechanised boats per day. The total employment generation capacity of this area is more than 10.000 people per day. S-IV. Dadanpatrabarh: This important fish-landing and processing centre is situated around 10 km away from Kontai subdivisional town by the side of sea. A total of 85 migrant fishers and around 200 local

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fisher families are engaged in fishing. Small patches of degraded mangroves have been thriving for their survival in the area. S-V. Junput: Junput, a small coastal village and an important fishlanding centre on Hoogli estuary is located 15 km east of Kontai. People belonging to below poverty line are engaged in fishing, especially for fish drying. A good patch of mangroves comprising namely of Rhizophora mucronata and Avicennia spp has come up in the intertidal zone. S-VI. Khejuri: Khejuri, a small coastal block with historical importance is situated near the Haldi river mouth. This was followed by a mangrove afforestation programme for 4 consecutive years viz. 1999 (10 hectors area), 2000 (10 hectors area), 2001 (10 hectors) and 2002 (15 hectors area) covering a total area of 48 hectors. This has resulted in the development of a healthy green patch of mangroves in this coastal tract. Besides others, grazing is the main problem to protect these plants. Small numbers of fishermen are engaged in fishing in the area. S-VII. Haldia: Haldia, a newly grown up industrial town in the district of Midnapore, West Bengal possesses a good number of industries like petroleum refineries, fertilisers, pesticides, battery, detergent etc. A large number of industries are located in close proximity of the confluence of the two estuaries, viz. Hooghli and Haldi, which are subjected to severe impact of pollutants discharge. S-VIII. Nayachar Island: The 46-sq. km Nayachar is a newly emerged island located (2154'41”- 2201'30”N & 88 03'00” 88 08'52”E) at the middle part of the macro- tidal estuary of Hugli River within the complex environmental setting of Bengal Delta system. After being raised considerably through continuous accretion of sediments, the surface of Nayachar Islands becomes colonised by salt marshes, the species association of which underwent through various series of succession with the changing bio-tidal environment associated with geomorphological dynamism (Paul, et.al., 2003-04). This island, formed out of sediment deposition during the past several decades, started accretion from 1945. Between 1967 and 1997, the island progressively enlarged, yielding an average accretion rate of 0.88 sq. km per year (Hazra and Sanyal, 1996). The island exhibits very rich


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biodiversity in terms of the salt marsh grass and swampy mangrove plant species along with various species of birds, fishes, plankton organisms, soil micro-arthropods and benthos (Dey, et. al., 2008; Khalua, 2003).’ S-IX. Kolaghat: The river Rupnarayan, one of the most important tributaries of the Hoogli, has been showing signs of rapid deterioration because of siltation resulting in navigation difficulties. In addition to the navigation difficulties, present trends of eco-degradation is likely to hamper the drainage of freshwater brought down by several freshwater rivers of South West Bengal, resulting in salinity invasion to all the estuarine networks of Midnapore coast. Kolaghat Thermal Power Plants which has been functioning since mid- eighties produce large amount of fly ash. This fly ash constituting very fine size of suspended particles has posed major ecological threats to adjoining water and soil ecosystem (Mishra, et. al., 2002). Geological and climatic factors of Midnapore coast: Beach profile: The beaches form linear coastal features, usually developed along the shoreline buffer to absorb or diminish and to reflect or transform the wave energy which is generated over the large areas of the Bay, both driven by winds and tides. Larger and flatter beach profiles of Midnapore coast are associated with beach berm, beach face, ridge and runnel, rip channels, low tide terrace, long shore trough, long shore bar and significant back wash ripples within the limits of back shore, foreshore, inshore and adjacent shallow water area of offshore zones. The beach face is marked by various sedimentological structures and active bioturbatious. The fine sand beaches of Midnapore coast have gentle foreshore slopes and provide a firmly packed hard sand surface for safe walking, playing, bathing and car driving. The beach provided with spits, are usually developed on drift alignment of long shore sediment. The amount of silt and clay fractions has increased in the extensive tidal flats of the lower foreshore region. Reduction of beach volume by attrition in Digha resulted in lowering of the beach planes (Chakraborty 1996). All motions on the sea surface are generated and controlled by a range of forces, viz. tides, waves and currents. Ripples and waves are generated by the wind and controlled by surface tension alone or in conjunction

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with storm. The waves in turn may generate coastal currents which are responsible for the sediment drifts along the beaches, i.e. long shore or littoral drift. Based on the nature of the tidal range, this coast is designated as Macrotidal to Mesotidal coast (Paul, 2002). Dunes: Coastal sand dunes are common geomorphological units in different parts of India. Dunes act as natural barrier to protect the coast from the damaging actions of wind, tide and wave, thus assuming a significant role in environmental protection. Recently, the long-term movement of shoreline obtained from the study of old survey report and new satellite data indicates that there is continued erosion at Digha proper but accretion at its western boundaries of Midnapore coast. Between 1877 and 1965, the beach-front-dune complex retreated landward by about 970 m at the rate of 11 m per year due to frequent marine transgression (Bhandari and Das, 1998). Sea level rise and erosion: Local sea level change and storm surge on seasonal effects or generation of waves of large height contribute to erosion over a time scale of hours to months. Comprising the annual sea level variation, it is observed that the annual mean sea level has risen steadily. In the Ganga-Brahmaputra delta, the suspended sediment load is high. If the sea level rise is being considered due to sedimentation load at the rate of 0.1 mm per year, the net rate of sea level rise would be 3.14 mm per year (Hazra, et. al., 2002). The causative factors of coastal erosion at Midnapore coast are identified as- (i) Strong littoral drift on a fine grained and flat beach bordered by dune in the landward side, (ii) loss of sandy materials inland by wind action, (iii) strong tides during cyclonic storm, (iv) possibility of faulting in the Digha shore- face in recent past and (v) bathymetry of the inner continental shelf and orientation of the ' Western Brace' with respect to Digha at its shore- face (Mukherjee and Chatterjee, 1997). With regard to the coastal erosion along the Digha-Dadanpatrabarh stretch, a general observation is that while the entire coastal stretch from Digha-Dadanpatrabarh to west Dadanpatrabarh is presently under severe coastal erosion, the eastern segment of DighaDadanpatrabarh coast near a small tidal estuary is under stable conditions leading to accreting condition. An acceleration of erosion is also noticed from the year 1994. In the Digha coast, several mouzas,


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which are still shown on the land use and land holding maps, have been engulfed by the sea during the last 30 years. The seawall was able to arrest the beach retreat but the beach lowering could not be protected. It was also noticed that the beach was steepened considerably after the construction of seawall, as compared to the preconstruction period (Hazra, et. al., 2001, Mukherjee and Chatterjee, 1997). Erosion and accretion: Historical records show that during the period 1877 and 1965, Digha shoreline of Midnapore coast moved inland by 970 m with an average retreat of 11 m per year. However, the rate of shoreline retreat has been increased sufficiently within the short-term period between 1965 and 1995 by 525 m with an average retreat of 17.5 m per year. To prevent such increasing erosion rate, the West Bengal Government constructed 4.7 km long sea wall with laterite stones in between 1972 and 1988 in the east west part of Digha. The sloping face of the sea wall touched the upper part of the beach plain and protected the bank line behind the long sea wall from open wave attack (Paul, 2002). Kolkata Port Trust also constructed a 2.8 km long guard wall on the northern end of Nayachar Island in Hugli estuary for improvement of the navigation channel of the Hugli river by diverting the eastern bank current to move along the Haldia bank during the ebb tide flow and down flowing river current. Several cross spurs have also been constructed along the northwestern bank of Nayachar Island in the same scheme of river training works (Dey, et. al., 2008). Natural causes of erosion: It is observed that the normal wave attack produces net loss of sediments by erosion in the lower part of the sandy beach during the southwest monsoon period. During this time, a spring tide level touches the base of beach-fringed dune and produces micro-cliff by erosion or by shoreward transport of unconsolidated dune sands. Even the stratified, grass covered large blocks or chunks of unconsolidated sediments have been observed to roll down after erosion by undercutting of sand bank in Hugli estuary within a short term period of tidal energy variation and wave activities. However, the enormous discharge of freshwater, carried by HugliRupnarayan-Kasai-Subarnarekha system, amplifies the tide and surge situations along with the seasonal high seas in the southwest monsoon brace.

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Beaches of Digha coast, Talsari, Junput and Shankarpur shoreline generally return to steeper reflective profile after the high energy wave event is over. Beach and dune erosion are the major thrust of this region due anthropogenic activity, recreational exploitation and unplanned urbanisation (Mukherjee and Chatterjee, 1997). Tides: The daily water level fluctuations of high tide and low tide and their cycle cause the changing water content of the beach and deposition tends to take place at the top of the beach at high tide and erosion as the tide falls. The mean range of the tide during springs at Haldia and Digha is 4.90 m, 4.20 m respectively. Meteorological data: Seasonal monsoon winds and maritime actions in the Bay of Bengal influence the tropical dry and wet climate of the region. The rainy season is largely confined to the months of June to October after a long dry spell of hot humid summer (Chandra et. al., 2008). Floral and faunal diversity Floral diversity of Midnapore coastal belt: Fifty seven species of mangroves and their associated plants from the intertidal, supralittoral and backshore zones under 32 families, 28 species of benthic algae under 4 families and 8 phytoplankton species under 3 families from the intertidal zone, supra-littoral brackish zone from the subtidal open estuarine marine zones of different habitats of contrasting ecological features have been recorded (Annon, 2005): Avicennia officinalis, A. alba, Exococaria agallocha, Acanthus ilicifolius Sueda maritima, Salicornia brachiata, Rizophora mucronata and Ipomea pescaprae, represent the major mangrove species. Dune growing plants such as Ipomea, Spinifix, Pandanus, etc. play a major role to stabilise dunes like the mobile dunes or the fore dunes, stabilised or back dunes. These species once established stabilise the shoreline and act as a buffer against erosion. It is observable that the gradual and orderly sequence of plant development from seaward to landward side is: (1) Spinifex littoreus formation on the beachfront seashore, (2) Ipomoea pes-caprae development on the mobile dunes, and (3) Casuarina-Ipomoea-Pandanus association on the fixed (stabilised) dunes. In highly unstable conditions, only low growing


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Spinifex littoreus with deeply penetrating root system survives (Bhakat, 2000; Bhakat, 2001). Faunal diversity of Midnapore coastal belt: Midnapore coastal belt in its extension of 60 Km encompasses a diversified habitats and niche which accommodate a galaxy of faunal components in the form of pelagic and benthic forms. Seventeen species of zooplankton mainly comprising of Copepoda, Chaetognatha, Rotifera and some considerable number of nauplii larvae have been recorded (Manna, et. al., 2008). A total number of 48 molluscan species belonging to 3 classes, 15 orders and 36 families have been reported from the intertidal habitats (Khalua, et. al., 2003).A total number of 22 polychaete species belonging to 10 families have been identified (Chandra, et. al.. 2008). A total number of 12 actinarian species belonging to 2 classes, 3 orders and 6 families have been recorded from different study sites. Besides, sea cucumber (Holothuroida), sea pen (Cnidaria), Lingula sp. (Brachyopoda), were found in the mudflats of Talsari, Shankarpur, Junput, and Nayachar Islands. Of the 68 arthropod species recorded from this coast,13 brachyuran crabs, 13 species of prawns and shrimps (21), 21 insects belonging to 33 families represent the major groups of fauna (Annon, 2005; Chatterjee, et. al., 2008). A total number of 51 soil microarthropods belonging to insect orders, viz. Collembola, Hymenoptera, Diptera and Isoptera, have been recorded from the different parts of this coast and they were found to play considerable role in estuarine-mangrove nutrient cycling (Dey, et. al., 2008 and Dey, et. al., 2009). Both the species of horse-shoe crabs, viz. Carcinocorpius rotundicauda and Taphypleus gigas, are also recorded from the Digha-Talsary intertidal flats (Annon, 2005). A total of 51 fish species under 2 classes, 9 orders and 25 families have been documented from different fish markets and landing centre (Annon, 2005). Fish landings at Midnapore Coast: Huge amount of eroded sediments, fly ash along with several other industrial discharges have made this vast sheet of water bodies almost unsuitable for living species. This is reflected by the steady decline of the abundance of fin fish and shell fish seeds, smaller fishes and other nektonic forms. It has been reported that an annual fish landing for 2003-2004 was 14,700.8-kg/yr.

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The data collected during the last ten years from the Department of Fishery, Government of West Bengal, relating to fish landings at DighaShankarpur Mohana, reveals a drastic reduction of total landings of different fishery resources. Operation of increased number fishing trawlers with nylon thread gears may be considered a major factor for such condition. Same trend was observed from the Junput fish landing centre and Dadanpatrabarh. The overall species wise analysis of the average catch for the three years showed that the highest contribution was from non-penaeid prawns (15.13%) followed by catfish (14.06%), pomfrets (10.33%), bombayduck (8.86%), croakers (8.2%), other clupeids (7.53%), anchovies (5.36%), hilsa (4.26%), ribbonfishes (6.2%), penaeid prawn (5.4%), seer fishes (2.33%), marine crabs (1.7%) and miscellaneous group of fin and shell fishes (10.56 %) (Annon, 2005). Status of coastal Pollution: source and nature of wastes Because of increasing urbanisation and industrialisation, throughout the Indian Ocean region, the load of sewage and industrial waste is constantly on the increase. Fertiliser, pesticides and insecticides are freely used in most developing countries for agriculture and pest and vector control. The quantities of pesticides and insecticides used every year vary from 45,000 tonnes in India to 3.5 tonnes in Bangladesh. In many countries, however, organochlorine pesticides are either prohibited or are gradually being replaced by organophosphorus and carbamate pesticides (Qasim, et. al., 1988). The water quality has deteriorated considerably in this coast because of discharges of untreated or partially treated sewage from the industries, municipalities, coastal towns. Natural habitats of the wetland swamps have also been affected seriously, as they have been used for industrial aquaculture. In many areas, saltmarshes and tidal floodplains of estuarine banks and tidal creeks have been used to develop fish farm in the protective flood banks for sustaining aquaculture. Increased soil salinity, viral infection among the fishes and contribution of pollutants to the sea waters are the adverse consequences of the present rapid growth of fish farming which has been developed without paying heed to coastal zone regulation acts (Chakraborty, 1998). It is well known that oil and other related organic products after being discharged from different fishing trawlers, barges, tankers, dredgers,


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ships and other marine vessels pollute considerably both pelagic and benthic environment. Domestic sewage in small quantities is known to fertilise the sea which leads to an increase in marine productivity (Qasim, et. al., 1988) because of eutrophication. Kolaghat Thermal Power Plant (KTPP) on the bank of Rupnarayan releases hot effluents and coal-burnt ash into this estuarine system (Mishra, et. al., 2002). Waste disposal from the tourist centers of Digha and nearby fishing harbours of Shankarpur contributes pollutants into the nearby estuaries and salt marshes. (Annon, 2005) Environmental impact of fly-ash disposal in estuary around Kolaghat thermal power plant In any thermal power station, fossil fuel such as coal is burnt and chemical energy contained therein is released in the form of heat by oxidation reaction. The outcome of such an operation is the contamination of the adjoining environment. Spatial and temporal variations of environmental factors over a year are considered to be important in generating information and in analysing the changes taking place within a stipulated span due to mixing of effluents with water. The ecological monitoring (bioresource availability and physiochemical parameters of the River Rupnarayan located adjacent to Kolaghat thermal power plant have been made by Mishra, et. al.. (2002). Impact of tourism Digha coast is the second highest revenue-earning tourist spot of West Bengal-only next to Darjeeling hill resort. Picnicking under the shades of Casuarina trees on the dune surface, walking and bird watching on the sand dunes, bathing in the beaches covered by sea water, car driving and horse riding on the beaches are the major features of recreational exploitation of the coast along this seaside tourist place. As a center of tourist attraction, Digha has gradually developed and the area witnessed an unprecedented construction boom just within the range of few hundred metres behind the sea wall. Many multistoried hotels have come up within a short distance of the sea wall especially in Old Digha. The indiscriminate installation of heavy tube wells into the dune bank has led to the collapse of subsoil layers and the resultant seepage of saline water into the drinking water. Another important feature is that the sea wall does not cover the most erosion prone areas to the east of Gobindabasan village, a stretch of 2km up to Digha estuary.

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Around 40 lakh people visit this coastal spot annually. Temporary fishing villages are being constructed on the dune slope which destroys the dune continuously in different study sites like Dandanpatrabar, Junput, Digha mohona fish landing center. Huge extraction of fluids from the near surface water table may often cause subsidence and saltwater percolation into the aquifer and thus increase the ground water salinity. This is observed in most of the study sites like Digha, Contai, Junput, Sankarpur and Haldia. Another threat to the coastal environment in general and biodiversity in particular is the development of Mandarmani tourist complex in the Dandonpatrabar, Purusottampur stretch of Midnapore coast violating the Coastal Zone Regulation Act. VIII. Trend of exploitation of ecologically and economically important finfish and shellfish species: Fishing with small meshed nylon nets reduces considerably the stock of juveniles, which are present in the fishing zone. It has been a regular feature especially around spring tide that local people in the process of collection of seeds of Paeneus monodon in saline stretch and Macrobrachium sp in fresh water dominated zone destroy a large amount of juveniles of other fishes like Mugil sp., Rhinomugil corsula, Gudusia sp., Liza sp., Tenualossa ilisha, Polynemus paradiseus, Lates calcarifer etc. along this coast. Besides, construction of fishing harbour and non- scientific fishing activities contribute to biodiversity loss (Annon, 2005). Acknowledgment The author is thankful to Ministry of Environment and Forest, Govt. of India for sanctioning a research project on Midnapore Coast and A. K. Paul, Mr. R. K. Bhakat, S. K. Dey and T. Bhattacharya for their suggestions. References Annon. 2005. Studies on bio-resource assessment and management of degraded mangrove ecosystem of Midnapore Coast, West Bengal, Research project report, Ministry of Environment and Forests. Govt. of India. [Sanction No. 3/6/2001-CSC (M) Dated. 5th Nov. 2001] pp. 1-99. Bhakat, R.K., 2000. An ecological study on dune stabilising plants of Digha for appropriate coastal afforestation. Indian Journal of Geography and Environment. 5, pp. 87-89. Bhakat, R.K., 2001. Coastal dunes of Digha, India- A plea for continued protection. Indian Journal of Geography and Environment. 6: pp. 54-60


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Bhandari, G.N. and Das, S.C. 1998. A study of beach erosion for appropriate protection of Digha Coast. In : Mukherjee, Ananda Dev; Datta, Kalyan Kumar; and Sanyal, Pranabes. (eds.), Coastal Zone Problems, Proceedings of National Workshop (March 20-22, 1998. Jadavpur University). pp. 51-60. Chakraborty, P. 1996. 'Map-info' in coastal zone management. In: Integrated Coastal Zone Management — A Manual. (Ed.) A.K. Ghosh and Pranabes Sanyal, Published by Department of Environment. Government of West Bengal. pp. 44-49 Chakraborty, S.K., 1998. Coastal Aquaculture and Environment in the context of West Bengal, India. Journal of Bio Sciences. 4. Vidyasagar University. Chanda, A and Chakraborty, S. K. 2008. Distribution, population and community ecology of Macrobenthic intertidal Polychaetes in the Coastal tract of Midnapore, West Bengal, India. Journal of Marine Biological Association. 50(1), pp. 7-16. Chatterjee, S.; Bhunia, G.; and. Chakraborty. S. K. 2008. Bioturbation of Brachyuran crabs and its impact on coastal ecosystem of Midnapore district, West Bengal, India. In: Proceedings of Fourth International Conference on Environmental Science and Technology 2008(II) at Houston, Texas U.S.A. pp. 133-148. Dey, M.K., Hazra, A.K. and Chakraborty, S.K., 2008. Diversity of Macroarthropods and their role in the plant litter decomposition in the coastal tract of east Midnapore District, West Bengal, India. Zoological Research in Human Welfare, 20. pp. 207-226. Dey, M. K.; Hazra, A. K. and Chakraborty, S. K. 2009. Functional Role of Microarthropods in Nutrient Cycling of Mangrove-Estuarine Ecosystem of Midnapore Coast of West Bengal, India. International Journal of Environmental Technology and Management, 10 (10), pp. 1-18. Hazra and Sanyal, A. 1996. Ecology of collembolan in a periodically inundated newly emerged alluvial island in the river Hoogly, West Bengal. Proceedings Zoology Society, Calcutta, 49(2). pp. 157-169.

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Hazra, S., Ghosh, T., Dasgupta, R. and Sen, G. 2002. Sea level and associated changes in the Sundarbans, Science and Culture. 68. pp. 309-321. Khalua, R.K., Chakravarty, G. and Chakraborty, S.K. 2003. Annotated list of molluscs from the coastal tract of Midnapore District, West Bengal, India. J. Marine Biological Association, 45(2). pp. 245-249 Manna, B., Banerjee, S., Aditya, G. and Chattopadhyay, J., 2008. Study of marine planktonic diversity in Digha coast, Bay of Bengal. Zoological Research in Human Welfare. 3. pp. 49-54. Mishra, S.S., Pradhan, P., Giri, S. and Chakraborty, S.K., 2002. Environmental Perturbation with regards to water quality and fishery resources of river Rupnarayan: a potential threat from a thermal power plant, West Bengal, India. In. Sustainable Development and cold water fish genetic resources. (Eds. S.R. Verma.), Nature Conservators. 7. pp. 155-172 Mukherjee, A.D. and Chatterjee, S., 1997. Coastal erosion and accretion at and around Digha in Medinipur District of West Bengal. Indian Journal of Geography and Environment. 2. pp. 1-11. Paul, A.K., 2002. Coastal Geomorphology and Environment. ACB Publications. 575 pp. Paul, A.K., Mukherjee, C.N., Bhattacharyya, P. and Mazumder, M. 2003-04. Environmental management and prospects of coastal tourism under the changing shoreline characters of Hugli-Subarnarekha complex. Indian Journal of Geography and Environment. 8 & 9. pp. 1-27. Qasim, S.Z., Sengupta, R. and Kureishy, T.W.1988. Pollution of the seas around India. Proceedings of Indian Academy of Science (Anim. Sci.). 97(2). pp. 117-131.

Marine Living Resources in the Practice of Traditional Medicine A. Chatterji*, Zaleha Kassim*, Anuar bin Hassan*, Amu Therwath1 and Faizah Shaharom* Abstract The knowledge of traditional medicines from marine resources shows that very little information has been preserved or recorded so far. We do not know how much information still exists, perhaps unconsciously, in the daily practices of rural workers or in the memories of old people. It is believed that much crucial information pertaining to traditional medicines from the sea have already been lost, and old men and women who still possess such knowledge have not passed it on to the next generation. There is some hesitancy observed in passing on this precious heritage either outside the family line or to those who do not appreciate these practices. Persons of middle age often recall the existence of such knowledge from their childhood, but for them it has fallen into disuse and their personal experience in its application is generally limited. The youth in general have seen no pertinence in such traditional medicines in their modern way of life. Now the time has come to put all our sincere efforts to collect all precious information of traditional medicines from marine life, and preserve and record them properly for future use.

Introduction Ocean is the treasure house of many living and non living resources, with about 26 phyla of marine organisms found therein. Arthropods contribute four fifths of all marine animals' species with over 35,000 varieties (Chatterji, 1994). Ancient Egyptian, Chinese and Indian documents show that medicine in these societies included numerous marine organism-based remedies and preventives. The Greeks and Arabs both contributed substantially to the assimilation, codification and development of these medicines (Mayer, 1978). It is generally believed that due to interactions between factors like ultraviolet rays from the Sun, lightening through electric charges, radioactive deposition of the crust and heat from volcanic activities, * Institute of Tropical Aquaculture, University Malaysia Terengganu, Malaysia. 1 University of Paris, France Jour. Coast. Env., Vol. 1, No. 1, 2010

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many organic compounds were formed (McAlester, 1968). Gradually the ocean changed into a soup of organic compounds and life came into existence. Enormous geological changes had occurred in the first billion years (Price, 1971). Some scientists believe that the first life appeared on earth is about two thousand million years ago. However, there is no significant evidence from which the date of origin of life can be ascertained, though it is a well known fact that the life emerged firstly in the sea in relatively late geological era. There was initially no free molecule of oxygen. However, during the long process of evolution, higher groups of marine organisms started emerging. The marine animals started using dissolved oxygen for breathing whereas, plants utilised dissolved carbon dioxide for making their food. Having somewhat exhausted easily accessible terrestrial sources, our ancestors went further in search of new medicines and began to explore the rainforests (Amazon, south East Asia etc). People in those days, however, realised that the wealth of the oceans, yet undiscovered, dwelled in the waters of different parts of the world, whether it is the arctic or other oceans. As such, marine organisms also started contributing some useful new therapeutic agents used in traditional medicinal practices all over the world. Pseudopterosins extracted from the Caribbean gorgonian (Pseudopterogorgia elisabethae) is useful as analgesic and anti-inflammatory agent; Manoalide from the sponge (Luffarriella variabilis) is an antiinflammatory agent; and Ziconotide and other new pain killers are derived from peptides from cone snail venom (Mayer and Hamann, 2000). For thousands of years, terrestrial plants have been considered as the basis for traditional medicinal systems with the first records dating from about 2600 BC in Mesopotamia. Our ancestors were utilising oils from cedar and cypress, licorice, myrrh and poppy juice for the treatment of a variety of diseases and infections. Surprisingly, approximately 80 percent of the world's population today relies on traditional plant-based medicines for primary health care. About 25 percent of the prescribed drugs dispensed in the United States contain plant extracts or active ingredients derived from plants (Mayer and Gustafson, 2006). Out of a total of 520 new drugs approved for commercial use between 1983 and 1994, 30 were new natural products and 127 were chemically modified natural products. Some

Marine Living Resources in the Practice of Traditional Medicine

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prominent plant-based medicines include Quinine from the bark of Cinchona species as an anti-malarial drug; Morphine from the opium poppy as analgesic; Digoxin from Digitalis purpurea for heart disorders; reserpine from Rauwolfia serpentine as antihypertensive agent traditionally used for snakebites and other ailments; Ephedrine from Ephredra sinica as an anti-asthma agent and Tubocurarine from Chondrodendron and Curarea species as muscle relaxant. This shows that marine animals have potential for directly benefiting human being in many forms of holistic care. This could especially be true in chronic cases where, many a times, regular modern medicine fails and traditional medicines are found effective (Mayer and Hamann, 2000). In Ayurveda practices, the use of marine organisms is known for centuries. The origin of Ayurveda is believed to be from 'Samudra Manthan' (churning of the sea) in which Amrut, the nectar of life, was produced. In Ayurveda practices, marine organisms are grouped in three main categories, namely animals, plants and minerals. Corals, pearls, shells, conch, sea salt, sea coconut etc are the main sea animals used for the preparation of different kind of drugs in Ayurveda (Chatterji, 1994). Horseshoe crab The horseshoe crab is believed to have appeared on earth in Precambrian geological time scale (Shuster, 1982). There are three species of the horseshoe crab found abundantly in Asia (Chatterji, et. al., 2008). Tribals inhabiting the north-east coast of Orissa, use the tail piece of the horseshoe crab to get relief from different types of pain by tying it on the arms or pricking it on the forehead (Mikkelsen, 1988). It has been reported that the tail tips are used for healing arthritis or other joint pain, and that they are sold by faith healers in West Bengal (Chatterji, 1994). In Singapore, pregnant women eat the egg mass of the horseshoe crab for immunisation of their foetus. The dead carapace of the horseshoe crab is boiled with mustard oil and used for treating rheumatic pain in many Asian countries (Mikkelsen, 1988).

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Seahorse Similarly, seahorse, another marine animal, is highly regarded and acclaimed in the Chinese medicine manuals which refer to it as being sweet in taste, warm in nature and that their active compounds enter the kidney and liver channels quickly (Sreepada, 2002). There are four commonly occurring species of seahorse found in the Asian waters: Hippocampus kelloggi (Kellogg's seahorse), H. histrix (thorny seahorse), H. kuda (yellow seahorse) and H. trimacullatus (low-crowned seahorse). The value of seahorses is spread from generation to generation via folklore. In China, about 20 million seahorses are caught each year from the wild and have been used as an ingredient in traditional medicine for approximately 600 years. Surprisingly, about 70 countries are involved in seahorse trading, with maximum supply coming from the Philippines, Indonesia and India. Though these animals are harvested throughout the year, they are found abundant in August and September. In Asia, people have been using seahorses for thousands of years as a cure for a variety of ailments. They are reported to play an important role in balancing vital energy flows within the body, cure of impotence and infertility, asthma, high cholesterol, goiter, kidney disorders and skin disease such as acne and persistent nodules formation. Impotence is generally treated with seahorses taken with rice and wine (Moreau, 1998). They are also used as a general tonic, powerful masculine stimulant and a potent aphrodisiac. A combination of seahorses with fruits or lean pork is very useful for treating frequent urination at night and weak constitutions in children (Lipton, 1998). Considering the extremely high demand for seahorses for traditional medicine, the Australians have launched a massive programme to cultivate seahorses under controlled conditions. Now they are in a position to breed large numbers of quality seahorses for the traditional Chinese medicine market. This will go a long way to help protect the wild population of seahorse around the world.


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Sea turtles There are eight species of sea turtles commonly occurring all over the world. Due to active fishing and destruction of the breeding beaches, all these turtles are now considered as threatened or endangered species. A large number of sea turtles are killed each year in fishing nets. As many as 115 countries have banned the trading in sea turtle products. However, the threats to sea turtles are not abating and some illegal trade in turtle products still continues. Even though attempts are being made to control international turtle trade, localised exploitation of turtles and eggs at the nesting beaches is still a problem. Sea turtles are only nominally protected by law in most countries where nesting occurs. For example, the extremely endangered Malaysian leatherbacks are still heavily exploited by the local population. On one nesting beach, 1,500 leatherbacks were counted in the 1950s, yet by the early 1990s fewer than 50 came ashore. A creative managed exploitation effort in Malaysia has been aimed at saving the species while allowing some human use of turtle eggs. Adult sea turtles are now strictly protected, but egg collection by licensed collectors is allowed. The government issues permits and then buys back a percentage of the collected eggs for captive incubation, hatching, and subsequent release of turtles to the wild. The leatherback is the largest sea turtle and reported to grow up to 2 m long and weigh 636 kg. The leatherback gets its name from its shell which is like a thick leathery skin with the texture of hard rubber. They are found throughout almost all the oceans of the world. It nests on tropical beaches in the Atlantic, Indian and Pacific Oceans. Their eggs are a prized food and used in traditional Asian medicines in most parts of the tropical world (Guo, et. al., 1998). Latin Americans use sea turtle eggs as an aphrodisiac and energising protein. In some part of the world, people harvest nearly 100 percent of eggs immediately after they are laid, thus resulting in significant decline of the population due to eggs being used in traditional medicine. (Guo, et. al., 1998; Fretey, et. al., 2007) Sperm whale An important compound known as Ambergris is produced by the sperm whale, a black, semi-viscous liquid that forms around the indigestible squid beaks. On exposure to sunlight and air, it quickly

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oxidises and hardens to a pleasantly aromatic, marbled, grayish, waxy substance in which the squid beaks are embedded (El-Kamali, 2002). When Ambergris is warmed, it produces a very pleasant, mild, sweet, earthy aroma, and has been used in the West since ancient times as a fixative for rare perfumes. It is said that a single drop of ambergris applied to a paper and placed in a book will remain fragrant even after 40 years and that, once handled the fingers will carry its scent for it several days even after several washings. Ambergris has been known in many parts of the world has been known to Arabs as 'ambar' and originally called as amber in the West. It has been reported to being used as medicine for heart and brain. Ancient Chinese referred to ambergris as lung sien hiang, 'dragon's spittle perfume,' because it was thought to have originated from the drooling of dragons sleeping on rocks at the edge of the sea. It is still known by this name, is used as an aphrodisiac and as a spice for food and wine. The Japanese have also known ambergris from ancient times and called it kunsurano fuu, 'whale droppings.' It was used to fix floral fragrances in perfumes. In addition to the common usage of making expensive perfumery, it has been used in the flavoring of dried fruit and tobacco. In India, ambergris is collected from the waters of the Andamans and exported at a very high cost for various applications. Sea cucumber In ancient times, sea cucumber was used as an important ingredient in Chinese food. The popular Chinese name for sea cucumber is haishen, which means, roughly, ginseng of the sea. It is often known in medical literature as fangcishen (fang = four-sided, ci = thorny; referring to the spiky protrusions that emanate from four sides) or, in abbreviated form, fangshen. The Asian demand for sea cucumber has been so high that these have been collected from the United States, Australia and the Philippines to meet its increasing demand. Though the Atlantic sea cucumber, Cucumaria frondosa was collected primarily for food, recently it has been found as an important source of medicinal components (Enchin, 1988). This has been the consistent efforts of Coastside Bio Resources in Maine that was headed by Peter Collin. Apart from having very low fat content, sea cucumber is an ideal tonic as it contains protein (~ 55%), more than any other food except egg whites (~ 99%); and it has 10-16% muco-polysaccharides, substances that are used to build the cartilage.


47

In traditional Chinese medicine, the sea cucumber has been reported to be used for treating disorders of the kidney system, including reproductive organs and moistening dryness of the intestines (Weici, 1987). It's most common medicinal uses China is for treating weakness, impotence, debility of the aged, constipation due to intestinal dryness and frequent urination. Sea cucumber is now considered as a valuable source of several kinds of important compounds that may be used as natural health products and perhaps could be developed as drugs. Since sea cucumber is consumed as a food by a very small segment of the population outside East Asia, its extracts could be put into easy-to-consume formats, such as capsules and tablets as most people do not have access to its beneficial components. Sea cucumber is having cartilaginous body and as such serves as a rich source of muco-polysaccharides, mainly chondroitin sulfate, which is well-known for its ability to reduce arthritis pain, especially osteoarthritis. Dried sea cucumber (3 g per day) has been reported to help in reducing arthralgia. Significantly, Russian, Japanese and Chinese studies have shown that sea cucumbers also contain saponins (triterpene glycosides), having a structure similar to the active constituents of ginseng, ganoderma and other famous tonic herbs. Pharmacology studies indicate antiinflammatory and anticancer properties of the sea cucumber saponins. Jellyfish In China, jellyfish have been exploited commercially and used an important food for more than a thousand years. Semi-dried jellyfish represent a multi-million dollar seafood business in Asia. Cannonball jellyfish collagen has shown a suppressing effect on antigen-induced arthritis in laboratory rats. Mucin, a protein substance, is also extracted from the jellyfish and used in drug delivery, cosmetic products and food additives. With the great abundance of cannonball jellyfish in the coastal waters, turning this jellyfish into value-added products could have tremendous environmental and economic benefits (Marx, 2006). Marine mollusks There are many natural remedies for acute or chronic pain due to simple arthritis or rheumatism with products of marine origin, which

48


give effective relief without the unwanted side effects of the use of steroid treatment. One such useful product for hip or joint pain is an extract prepared from green mussel, a marine bivalve, belonging to mollusks group (Plate III). For years, they have been used to treat degenerative joint disease (Chatterji, et. al., 2002). This mollusc contains many bioactive compounds including glycosaminoglycans, an anti-inflammatory and an antihistamine compound. Green mussel has been shown to reduce the inflammation of rheumatoid arthritis and degenerative joint disease of the stifle. It enhances the regenerative capacities of joint chondrocytes, regulating the chondroitin sulfates and hyaluronic acid production needed to maintain healthy chondrocytes. Oysters and clams (Plates IV and V), on the other hand, have been reported by the Romans in the second century A. D. as good aphrodisiac agents (Chatterji, et. al., 2002). Seaweeds In Chinese traditional medicinal practices, kelp (Laminaria) and Sargassum both brown algae (Plate VI) and Pyrphora red algae (Plate VII) is commonly used to prevent joint pain from inflammation. These age-old proven weeds are wonderful in solving many problems related to bones and, at the same time, help in normalising thyroid and reproductive functions. Seaweeds have been reported to draw wealth of mineral elements from the sea that can account for up to 36% of its dry mass. The mineral macronutrients consist of sodium, calcium, magnesium, potassium, chlorine, sulfur and phosphorus, whereas the micronutrients include iodine, iron, zinc, copper, selenium, molybdenum, fluoride, manganese, boron, nickel and cobalt (Hong et.al., 2004).


49

Seaweeds have a large proportion of iodine as compared to dietary minimum requirements brown algae have the highest iodine content ranging from 1500-8000 ppm. Daily requirement of iodine for adults is currently recommended at 150 µg/day and as such a very small quantity of seaweed is required to meet its demand one gram of dried brown algae provides ~500-8,000 µg of iodine. Studies show that the human body adapts readily to higher iodine intake, where the thyroid gland is the main tissue involved in the use of iodine. It has been reported that a large number of people all over the world do not get sufficient iodine because the land, plants and animals, that serve as common dietary sources, are very low in iodine. In many countries, iodine is added to table salt in order to assure adequate supply of iodine to human body. However, some developing countries are still lagging behind and suffering from the effects of low iodine intake China has the largest population with a history of low iodine intake, followed by India. Seaweeds are one of the richest plant sources of calcium (4-7% of dry matter). One gram of dried seaweed provides 70 mg of calcium as compared to a daily dietary requirement of about 1,000 mg. So, the calcium requirement is still higher than a serving of most non-milk based foods. Similarly, the protein content in seaweeds varies from species to species from 5-11% to 30-40%. Spirulina, a micro-alga, is well known for its very high protein content ranging up to 70% of dry matter. Seaweeds have also been reported to contain several important vitamins Red and brown algae are rich in carotenes (provitamin A) and are used as a source of natural mixed carotenes for dietary supplements (Dillehay, et. al., 2008). Its content ranges from 20-170 ppm. The vitamin C in red and brown algae has been found ranging from 500-3000 ppm. Vitamin B12 which is not found in most terrestrial plants is also present in seaweeds. Seaweeds have very little fat ranging from 1-5% of dry matter. They have high fiber content, making up 32 to 50% of dry matter. The soluble fiber fraction accounts for 51-56% of total fibers in green algae (Plate VIII) and red algae and for 67-87% in brown algae. Soluble

50


fibers are generally helpful in lowering cholesterol levels and have also shown hypoglycemic effects. The use of seaweeds in Chinese traditional medicine has been described in detail in Oriental Materia Medica (2). Laminaria and Sargassum generally enter the liver, lung, and kidney meridians. Both can clear heat, transform phlegm, soften hardness and dissipate nodules. These species can also promote urination, and reduce edema, goitre, testicular pain, swelling and scrofula. Porphyra is stronger in softening hardness and reducing congealed blood, it is more suitable for treating liver-spleen enlargement, liver cirrhosis, sore throat and tumours. Seaweeds have been reported to be used for treating soft swellings, including ovarian cysts, breast lumps, lymph node swellings, lipomas, and fat accumulation from simple obesity. Mangrove plants Mangrove plants are commonly used directly as a food source, probably due to the high levels of tannins and other distasteful chemicals. These are flowering plants and their flowers are a likely source for honey. Native bees are found in the mangroves during various flowering seasons, and are exploited now by commercial apiarists with their exotic bees. Mangroves plants are used for medicinal purposes for many years in some cases the plant or its sap is used directly whereas in other cases the leaves may be heated or the plant material burned to an ash for various applications such as skin sores and scabies, leprosy sores, smoke for making babies strong, body pain, boils, washing wounds, headaches, splints for fingers, toothache, ulcers and yaws (Bandaranayake, 1998). Acknowledgments The authors are grateful to the University Malaysia Terengganu for awarding a Research Fellowship to one of the authors, (Anil Chatterji) for completing this manuscript. References Bandaranayake, W.M. 1998. Traditional and medicinal uses of mangroves. Mangroves and Salt Marshes, 2(2), pp. 133-148. Chatterji, A. 1994. The Horseshoe Crab — A Living Fossil. A Project, Swarajya Publication. 157 pp.


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Chatterji, A., Ansari, Z. A., Ingole, B. S, Bichurina, M. A., Sovetova Marina and Boikov Yuri A. 2002. Indian marine bivalves: potential source of antiviral drugs. Current Science, 82 (10), pp. 1279-1282. Chatterji, A. Kassim, Z., Shahuddin, H. and Shaharom, F. 2008. Abundance of three species of the horseshoe crab along the coast of Malaysia, Journal of Bombay Natural History Society (unpublished data). Dillehay Tom D., Pino Ramirez, M. C., Collins, M. B., Rossen, J. and Pino-Navarro, J. D. 2008. Monte Verde: Seaweed, Food, Medicine, and the Peopling of South America, Science, 320 (5877), pp. 784 786. El-Kamalih, H. 2002. Folk medicinal use of some animal products in Central Sudan, Journal of Ethnopharmacology, 72, pp. 279-282. Enchin Zhang. 1988 Chinese Medicated Diet, Publishing House of Shanghai College of Traditional Chinese Medicine, Shanghai. 69 pp. Fretey Jacques, Segniagbeto Gabriel Hoinsoude and Soumah M'Mah. 2007. Presence of Sea Turtles in Traditional Pharmacopoeia and Beliefs of West Africa, Marine Turtle Newsletter, 116. pp. 23-25. Guo Yinfeng, Zou Xueying, Chen Yan, Wang Di and Wang Sung. 1998. Sustainability of Wildlife Use in Traditional Chinese Medicine. 48 pp. Hong, D. D. Hien, H. M. and Son, P. N. (2004). Seaweeds from Vietnam used for functional food, medicine and biofertiliser. Journal of Applied Phycology, 22, pp. 323-325. Lipton, A. R. 1998. Project Sea Horse. In: Proceedings of the First International Workshop on the Management and Culture of Marine Species used in Traditional Medicines. Montreal, Canada, pp. 7577. Marx J. Rosen, Hockberger Robert S. and Walls Ron, M. 2006. Emergency Medicine: Concepts and Clinical Practice. 6th ed. St. Louis, Mo: Mosby Inc. pp 67. Mayer, E. 1978. Evolution. W.H. Freeman and Company, San Francisco, 135 pp.

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Mayer A. M. S. 1999. Marine Pharmacology in 1988: antitumor and cytotoxic compounds. The Pharmacologist, 41. pp. 159-64. Mayer, A.M.S. and Hamann, M.T. 2000. Marine Pharmacology in 1999: compounds with antibacterial, anticoagulant, antifungal, antiinflammatory, anthelmintic, anti-inflammatory, antiplatelet, antiprotozoal and antiviral activities; affecting the cardiovascular, endocrine, immune and nervous systems and other miscellaneous mechanisms of action. Comparative Biochemistry and Physiology Part C: Pharmacology, Toxicology and Endocrinology, 132. pp. 315-339. Mayer, A.M.S. and Gustafson, K. R. 2003. Marine pharmacology in 2000: Anti-tumour and cytotoxic compounds. International Journal of Cancer, 10. pp. 291-299. Mcalester, A. L. 1968. The Histor y of Life, Prentice-Hall, Inc., Englewood Cliffs, New Jersey, pp 152. Mikkelsen, T. 1988.The Secret in the Blue Blood. Science Press Beijing, China, 124 pp. Moreau, M. A., Hall, H. J. and Vincent, A.C.J. 1998. Project Sea horse. In: Proceedings of the First International Workshop on the Management and Culture of Marine Species used in Traditional Medicines, Montreal, Canada, pp. 240. Price, J. T. 1971. The Origin and Evolution of Life. The English University press Ltd., London, 113 pp. Shuster, C. N., Jr. 1982. A pictorial review of the natural history and ecology of horseshoe crabs Limulus polyphemus, with reference to other Limulidae. In: Physiology and Biology of Horseshoe Crab: Studies on Normal and Environmentally stressed animals. (Eds.). J. Bonaventura, C. Bonaventura and S. Tesh. New York : Alan R. Liss. 51 pp. Sreepada, R. A., Desai Ulhas, M. and Naik Sushant. 2002 The plight of Indian sea horses: Need for conservation and management, Current Science, 378 (82). pp. 377- 378. Weici Tang. 1987. Chinese medicinal materials from the sea, Abstracts of Chinese Medicine, 1(4). pp. 571-600.

Energy Efficiency in Trawling Operations *

1

2

M.R. Boopendranath , V.C. George and M. Shahul Hameed Abstract

Diurnal variation in trawl catches and its influence on energy efficiency of trawler operations are discussed in this paper, based on data on landings of a Japanese factory trawler which operated in the Indian waters during 1992-93. The factory vessel equipped for stern trawling had a length overall of 110 m, GT of 5460 and installed engine power of 5700 hp. Operations were conducted off the west coast of India between 31 and 278 m depth contours, using a 80.4 m high opening bottom trawl with an adjusted vertical opening of 7.60.9 m. The catch data were grouped according to the median towing hour, by the time of the day. CPUE obtained was 3713.4 kg.h-1 for day time operations and 1536.6 kg.h-1 for night-time operations. Mean daily catches were 31367 kg.day-1 (SE: 2743) for day time operations and 9430 kg.day-1 (SE: 966) for night-time operations. Fuel consumption was 0.399 and 0.982 kg fuel.kg fish-1, respectively for the day and night-time operations. Total catch and catch components, such as threadfin bream, bull's eye, hair tails, trevelly, lizard fish, showed significant improvement during the day-time operations, while swarming crabs showed a significant improvement in the night-time operations. The difference in catch rates between day and night could be attributed to diurnal variation in the spatial distribution and schooling behaviour of the catch categories, their differential behaviour in the vicinity of trawl systems under varying light levels of day and night and consequent effect on the catching efficiency and size selectivity at different stages in the capture process. The results obtained in addition to its importance in the operational planning of trawling in order to realise objectives of maximising catch per unit effort and minimising fuel consumption per unit volume of fish caught, has added significance in the use of bottom trawl surveys in stock abundance estimates. Keywords: Diurnal variation; Trawl catches; Energy efficiency

Introduction Trawl catches are known to vary throughout the day (Woodhead, 1964; Beamish, 1966; Shepherd and Forrester, 1984; Ehrich and Groger, * Principal Scientist, Central Institute of Fisheries Technology, Cochin Department of Aquaculture, Sacred Heart College, Thevara, Cochin 2 School of Industrial Fisheries, Cochin University of Science and Technology, Cochin 1

Jour. Coast. Env., Vol. 1, No. 1, 2010

54


1989; Neilson and Perry, 1990; Ferno and Olsen, 1994; Francis and Williams, 1995; Freon et. al., 1996; Casey and Myers, 1998; Freon and Misund, 1999; Hjellvik et. al., 2002; Adlerstein and Ehrich, 2003; Axenrot et. al., 2004). The differences in length distribution and species composition between day and night catches of beaked red fish were analysed by Atkinson (1989). Analysis of trawl survey results by Hylen et. al., (1986) with respect to north-east Arctic cod and haddock stocks and by Godo and Wespestad (1990) on gadoids revealed a sampling problem in stock assessment surveys involving a complex set of factors including diel variation in the vertical distribution of fish. Results of a study conducted by Engas (1991) have shown diurnal variation in bottom trawl catches of cod an haddock and its influence on abundance indices. Woodhead (1964) studied the diurnal changes in trawl catches of fishes. Beamish (1966) studied the vertical migration of demersal fish in the north-west Atlantic. Shepherd and Forrester (1987) reported diurnal variation in the catchability during bottom trawl surveys off north-eastern United States. There have been no studies so far on diurnal variation in the trawl catches from the Indian Ocean region. Materials and Methods Data on trawl catches obtained during 4 cruises of a Japanese factory trawler which operated in the Indian waters during 1992-93, were utilised for this study. The factory vessel equipped for stern trawling has a length overall of 110 m, GRT of 5460 and an installed engine horse power of 5700 hp at 300 rpm. The vessel is a commercial deep sea stern trawler with onboard facilities for processing of surimi (washed and stabilised fish mince), fish fillets and fish meal. Operations were conducted off south-west coast of India, between latitudes 16° and 7° N (Fig. 1). The depth of operations ranged from 30 to 360 m, with 68% of the observations falling between 50 and 140 m depth contours. A Japanese bottom trawl of 80.4 m head line length rigged with bobbin gear for rough bottom conditions, were used for the operations. Details of rigging are given Fig. 2. Bobbin gear consisted of 530 mm dia rubber and 300 mm dia steel bobbin weighing 5975 kg in the air. Average tow duration during the period of operations was 2.7 h and mean towing speed measured using Doppler log was 4.0 0.6 kn.

Energy Efficiency in Trawling Operations

Fig. 1

Trawling stations

Fig. 2

Rigging details of 80.4 m Japanese bottom trawl

55

56


Trawl geometry was estimated from data obtained from Net recorder (Furuno Electric Co., Japan) with sensors for measuring vertical opening and Otter graph (Kaiyo Denki, Japan) with sensors for depth and horizontal opening between the otter boards. The gear was so rigged as to attain a vertical opening of 10 m and it assumed ellipsoidal mouth configuration by providing wing-end strops and adjusting floatation, to suit the tropical demersal shoal characteristics. Catch data were grouped according to the time of the day and night using the median towing hour (calculated as the hour of starting the tow plus half the tow duration). Hauls taken between local sunrise and sunset were classified as day-time hauls and those made after sunset and before sunrise as night-time hauls. The difference in catch per unit effort (catch per hour) with respect to different species groups and total catch, between day and night-time hauls were analysed using Student t test after logarithmic transformation of the data (Motte & Iitaka, 1975). In addition to total catch, the species groups analysed were threadfin bream (Nemipterus spp.), bull's eye (Priacanthus spp.), lizard fish (Saurida pp.), hairtails (Trichiurus spp.) trevally (Caranx spp.), perches (Epinephelus spp., Lutjanus spp. Lethrinus spp.), swarming crabs (Charybdis spp.), cephalopods (squids and cuttlefishes) and miscellaneous fish. Catches were obtained for 8 h trawling period for day and night, as 8 hours are conveniently available for towing in 12 h period of day or night allowing for time spent for shooting, hauling and ground shifting, etc. Normalised catch data were used to estimate the percentage split between day and night operations, of the total catch and catch components. Fuel consumption per kg of fish landed was estimated from the catch data and fuel expended for 12 h duration of the day or night. Daily fuel consumption per kg of fish landed were subjected to Student t test after logarithmic transformation of data, to determine if there is any significant difference between day and night fuel consumption per unit volume of the fish landed. Results Average vertical opening of the trawl mouth was 7.60.9 m. Mean horizontal opening between otter boards was determined to be 116.74.7 m. Horizontal opening between wing-ends was estimated to be 34 m which is 44 % of the head line length of the trawl. Area of


57

the trawl mouth for the assumed ellipsoidal shape of the trawl mouth was estimated to be 209 m2 and the volume of seawater filtered per 3 trawling hour at 4.0 kn towing speed was estimated to be 1504636 m . Total landing during the four cruises conducted off the south-west coast of India was 3528.5 tonnes. 466 hauls were taken with a total duration of 1254.1 hours. Of this, 2697.6 t was landed during 280 hauls taken during the day-time from sunrise to sunset, expending 726.5 h. and 811.0 t was landed during 186 hauls taken in the night hours from sunset to sunrise, expending a total of 527.7 h. Variations in catch volume, catch rate and percentage composition of the daytime and night- time, and day and night hauls during the period of observations are given in Table 1. Table 1 Day-time Hauls

Species groups

Total CPUE, catch, kg.h-1 kg 2165.43

Night-time Hauls

Day Hauls %

and Night

%

Total CPUE, catch, kg.h-1 kg

Total CPUE, catch, kg.h-1 kg

%

58.31

467527 886.03 57.65 2040604 1627.12 58.16

Threadfin bream

1573077

Bulls eye

106766

146.97

3.96

15638

29.64

1.93

122404

97.60

3.49

Lizard fish

87981

121.11

3.26

23113

43.80

2.85

111094

88.58

3.17

Hairtails

78420

107.95

2.91

496

0.93

0.06

78916

62.93

2.25

Trevally

73393

101.02

2.72

805

1.53

0.10

74198

59.16

2.11

Perches

45331

62.40

1.68

15699

29.75

1.94

61030

48.66

1.74 1.73

Swarming crabs 17252

23.75

0.64

43573

82.52

5.57

60825

48.50

Scad

28854

39.72

1.07

2894

5.49

0.36

31748

25.32

0.91

Cephalopods

22116

30.42

0.82

8935

16.93

1.10

31051

24.76

0.89

Horse mackerel

2694

3.71

0.10

0

0.00

0.00

2694

2.15

0.08

Barracuda

1065

1.47

0.04

0

0.00

0.00

1065

0.85

0.03

Miscellaneous catch

660651

909.42

24.49

Total catch

2697600

3713.40 100.00

232270 440.18 28.64

892921

711.99 25.45

810950 1536.88 100.00 3508550 2797.62 100.00

Variation in catch volume, catch rate and percentage composition of day-time, night- time and day and night hauls

The overall catch per hour during the period of operations was 3713.4 -1 -1 kg.h during the day-time operations and 1536.8 kg.h during the


58

-1

night time operations, and daily catch was 31367.4 kg.day (SE: -1 2743.0) for day-time operations and 9429.7 kg.day (SE: 965.6) for night-time operations. Estimates of catches normalised for 8 h trawling period, were 29707 kg and 12295 kg, respectively, for day and night operations and the total for the entire day was 42002 kg. Estimates of normalised catch rates for important catch components such as threadfin bream, bulls eye, lizard fish, hairtails, trevally, perches, swarming crabs, cephalopods, scad, horse mackerel, barracuda and miscellaneous catch for both day and night operations are presented in Table 2 and percentage split between normalised day and night catches is given Fig. 3. Table 2 Catch categories

Day-time catch kg

Night-time catch kg

Threadfin bream

17323

7088

Bulls eye

1176

237

Lizard fish

969

350

Hairtails

864

8

Trevally

808

12

Perches

499

238

Swarming crabs

190

661

Scad

318

44

Cephalopods

244

136

Horse mackerel

30

0

Barracuda

12

0

Miscellaneous catch

7275

3521

Total catch

29707

12295

Comparison of catches normalised for 8 h trawling period and percentage split of total catch and component groups between day-time and night-time catches.

The total fuel consumption for the period of operation was 2,060 tonnes which is equally split between day and night operations. Estimates of the fuel consumed per unit of fish production were


59

Fig. 3

Percentage split between normalised day and night catches

estimated from the catches during the period of operations. These were 0.399, 0.982 and 0.568 kg fuel.kg fish-1, respectively for day, night and combined period of operations (Table 3). Table 3 Day

Night

Day & Night

Total catch normalised for 8 h effort per day for 86 days, kg

2554802

1057370

3612172

Total fuel consumption for 86 days, kg

1029934

1029934

2059872

Fuel consumption, -1 kg fuel kg fish

0.403

0.974

0.570

Fuel consumption per unit volume of fish caught during day, night, and day and night hauls

60


Discussion Trawl operations were carried out continuously during the 24 h period within a depth strata 30 -360 m, with the 95 % of the operations falling within 180 m depth contour, between latitudes 16° and 7° N, off south-west coast of India. During the period of operations, the vessel spent on an average 16.2 % time for sailing and ground shifting, 6.5 % for shooting operations, 57.9 % for towing the gear, 7.9 % for hauling and the balance for performing miscellaneous functions. The catch data showed large diurnal differences in the volume of total catch and catch components and in the catch composition. Catch per unit effort (CPUE) in terms of total catch was 3,713.4 and 1,536.9 kg.h-1, respectively for day and night operations (Table 1). The percentage improvement in CPUE realised during the day-time was over 140 % compared to night operations. The difference in daily catch rates between day and night was found to be statistically highly significant (p