Plasma Osmotic and Electrolyte Concentrations of. Largemouth Bass from Some Acidic Florida Lakes 1. DANIEL E. CANFIELD, JR. AND MICHAEL J. MACEINA ...
Transactionsof the American FisheriesSociety 114:423-429, 1985 ¸ Copyrightby the AmericanFisheriesSociety1985
Plasma Osmotic and Electrolyte Concentrationsof
Largemouth BassfromSomeAcidicFloridaLakes1 DANIELE. CANFIELD, JR.ANDMICHAEL J. MACEINA 2 Departmentof FisheriesandAquaculture FRANK G. NORDLIE
Department of Zoology
JEROME V. SHIREMAN
Departmentof FisheriesandAquaculture Universityof Florida, Gainesville,Florida 32611 Abstract
Five acidicclear(pH 3.7-4.9), three acidiccolored(pH 4.1-4.6), and three neutral(pH 6.9-7.3) north-centralFlorida lakeswere surveyedin 1983 to determineplasma osmoticand electrolyte
concentrations, growth,and coefficients of conditionfor largemouthbassMicropterussalmoides floridanus.Plasmaosmoticconcentrations averagedgreaterthan 273 milliosmoles/kgin fishfrom acidiccoloredand circumneutrallakes,but averagedlessthan 269 milliosmoles/kgin four of the acidicclearlakes.Growth and coefficientsof conditionof largemouthbass> 305 mm total length in the acidiclakesweresignificantly lowerthan in the neutrallakes.Reductionsin fishgrowthand condition,however,could be relatedto either acidic conditionsor lake trophic status. ReceivedApril 22, 1984
AcceptedFebruary28, 1985
A third to a half of Florida's 7,700 lakes may
In this paper, we examine plasma osmotic and
be sensitive to (unable to buffer) acidification electrolyteconcentrationsof naturally occurring from atmospheric deposition (Canfield 1983; Florida largemouthbassMicropterus salmoides Hendry and Brezonik 1984). Potential responses floridanus from some acidic and circumneutral of the biota of these lakes to acidification
are
undetermined.Phytoplankton,zooplankton,and benthic
invertebrate
abundances
are lower
in
acidic Florida lakes than in neutral ones (Crisman and Brezonik 1980; Crisman et al. 1980; Beaver and Crisman 1981), but the acidic lakes also have lower phosphorus and nitrogen concentrationsand this, rather than acidity, may be
Florida lakes. Reductions in plasma electrolytes occurwhen fish are exposedto acidic stress(Leiyestad and Muniz 1976; Wood and McDonald 1982). Loss of plasma electrolytes generally is
accompaniedby a reduction in blood pH, an increase in hematocrit and hemoglobin, and a risein blood viscosityand arterial pressure,which can lead to circulatory failure (Wood and the primary constrainton biologicalproduction McDonald 1982). We use plasma osmotic and in such lakes (Canfield 1983). Acidification of electrolyte data, as well as data on growth and northern lakes has causedfish mortality and re- condition factors, to determine if existing acidic productive failure (reviewed by Haines 1981), conditions cause physiological alterations in but fish survive and reproduce in some acidic
largemouth bass of Florida lakes. We also at-
Florida lakes at pH values equal to or below
tempt a preliminary assessmentof the potential vulnerability of Florida's largemouth bass populations to damageby acidification.
those of damaged ecosystemsin the north (Canfield 1983). Little else, however, is known about
the responseof Florida fish to acidity.
Methods
Eleven
1 JournalSeries5562 of the FloridaAgriculturalExperiment Station.
2 Presentaddress:Departmentof Wildlife andFisheries Sciences,Texas A&M University, College Sta-
north-central
Florida
lakes were sam-
pled once each for water chemistry and largemouth bass between August 10 and November 7, 1983. The lakes were selected to represent
three common Florida lake types: acidic clear;
tion, Texas 77843. 423
424
CANFIELD ET AL.
acidic colored; and circumneutral. Lakes Brooklyn (29ø48'N, 82ø03'W), Clear (29ø40•N, 82ø02'W), Cowpen (29ø36'N, 82ø00'W), Cue (29ø41'N, 81ø58'W), and Long (29ø41'N, 82ø00'W) are acidic, clear lakes in a geographic region where most lakes are oligotrophic and
acidic (Canfield 1981). Fisheriesand limnological data for these lakes, however, are sparse or
nonexistent. Lakes Hourglass (29ø40'N, 81ø56'W), Ocean Pond (30ø13'N, 82ø26'W), and Palestine (30ø07'N, 82ø25'W) are acidic colored lakes. They are oligomesotrophic or mesotrophic (Canfield 1981). There are no fisheriesdata for Hourglass Lake; Ocean Pond and Palestine Lake have self-sustaining largemouth bass populations. Lakes Alice (29ø39rN, 82ø22'W), Newnans (29ø40'N, 82ø13'W), and Wauberg (29ø39'N, 82ø18'W) are circumneutral lakes.They are highly eutrophic (Canfield 1981), but support viable largemouth bass populations. Surface water (0.5 m) samples were collected from
three
midlake
and three littoral
stations
(stations were chosen at random) just prior to fish sampling at each lake. At each station, pH was measured with an Orion Model 601A pH meter calibrated against buffers at 4.0 and 7.0. Surface water temperatures were measured with a Yellow Springs Instrument Model 57 oxygen meter. Water samples then were placed on ice until chemical analyses could be completed the
speed on a Damon/International Equipment Corporation clinical centrifuge. Plasma was removed with a steriledisposablepipetteand placed in a sterile glass storage tube. Plasma samples were placed on ice until they were returned to the laboratory where samples were frozen. Each fish was given an identification mark and placed on ice for later analyses. At the laboratory, pH of the lake water was measured again with the same meter. Total alkalinity was determined by titration with 0.02 N sulfuric acid (APHA et al. 1975). To standardize titrations and avoid possible interference from silicates, phosphates, and other materials, all
sampleswere titrated to a pH of 4.5 (APHA et al. 1975). Becausethe equivalence point occurs at pH above 4.5 in low-alkalinity samples, reported alkalinities may be greater than true alo kalinities. Specificconductance was measured at 25øC with a Yellow Springs Instrument Model 31 conductivity bridge. Calcium and magnesium concentrationswere determined by atomic absorption spectroscopyand sodium and potassiuim concentrations were determined by flame photomerry with a Perkin-Elmer Model 703 atomic absorption spectrophotometer. Chloride concentrationswere determined with a diphenylcarbazone
indicator
and titration
with
0.141
N
mercuric nitrate (Hach Chemical 1975). Sulfate wasmeasuredby a turbidimetric method (APHA next day. After all water sampleswere collected, et al. 1975). Aluminum concentrations were 8 to 12 aduR largemouth bass were captured for measuredby the aluminon method (Hach Chemblood analysis.Small largemouthbass(• 200 mm ical 1975). Total nitrogen was determined with total length, TL) also were collected for age and a modified Kjeldahl technique (Nelson and Somgrowth analysesand to determine if reproduction mers 1975) and total phosphorus was measured had occurred during 1983. We selected electro- by the proceduresof Murphy and Riley (1962) shocking as the method of capture in order to with a persulfate digestion (Menzel and Corwin minimize physiologicalchangesthat might occur 1965). Color was determined by the platinumdue to fish capture (see Mazeaud et al. 1977). cobalt method and Nessler tubes (APHA et al. Burns and Lantz (1978) demonstrated that elec- 1975). For chlorophyll-a analysis, a measured troshocking had no effect on largemouth bass volume of lake water was filtered through a Gelhemoglobin, hematocrit, plasma protein, or tis- man A-E glassfiber filter. Filters were storedover desiccantand frozen until analyzed. Chlorophyll sue water content and Schreck et al. (1976) showedthat electroshockingdid not alter plasma was extracted by the methods of Yentsch and calcium or magnesium concentrations in rain- Menzel (1963). Spectrophotometric measurebow trout Salmo gairdneri. Upon capture, fish ments were made according to Richards with were immediately removed from the collecting Thompson (1952), but chlorophyll-a values were net and a 1- to 4-ml sample of whole blood was
calculated from the equations of Parsons and
taken from the duct of Cuvier in an ammonium-
Strickland (1963). Corrections for pheophytin
heparinized syringe. The whole blood was immediately placed in a 10-ml heparinized centrifugetube and centrifugedfor 5 min at maximum
were not made.
Fish plasma osmotic concentrations were determined with a Wescor Model 5100B vapor
LARGEMOUTH BASS PHYSIOLOGY IN ACIDIC FLORIDA LAKES
pressure osmometer. Plasma sodium concentrations were measured
with a Radiometer
Model
FLM 2 flame photometer and chloride concentrations with a Radiometer
Model CMT
10 chlo-
ride titrator. Plasma potassium concentrations
425
0.09 mg/L (Ocean Pond), which is below proposed toxic aluminum concentrations. Most of the aluminum probably is complexed with organic ligands, which would further reduce the potential for aluminum toxicity (seeBaker 1982). The only lakes that did not have potentially
were measuredby flame photometryon a Varian Techtron Model 1200 atomic absorption spec- stressfulacidityor aluminum concentrations were trophotometer.
Each largemouth bass was measured to the nearestmillimeter (TL) and weighedto the nearest 0.1 g. Where possible, sex of the fish was determined. Fish were agedfrom otoliths (Taub-
err and Tranquilli 1982), and lengthsat agewere back-calculatedby direct proportion: Oi/Or = TLi/TL; Oi is the radius of the ith annual otolith ring; Or is the otolith radius to the outside edge; and TL i is the calculated total length at age i.
the circumneutral lakes, whose average field pH ranged from 6.8 to 7.3 and whose average aluminum concentrationswere lessthan 0.06 mg/L. Mean color values ranged from 40 to 80 PCU and calcium concentrations(5.9 to 23 mg/L) averaged significantly higher than in the acidic lakes. We do not have long-term water chemistry data for the study lakes, but their chemistries are similar
to those of other lakes located
on the
same geologicformations (Canfield 1981). Stud-
Conditionfactors Kwerecalculated byK = 105W/
ies of other lakes in north-central
TL3; W is wetweight(g).
cate seasonalwater chemistry changesare small (Brezonik et al. 1982). Thus, fish in the study lakes have most likely been experiencing water chemistriessimilar to thosemeasuredduring this study for a long time. Relative to those of large-
Descriptive statisticswere calculatedwith programs of the Statistical Analysis System (SAS 1982). Unless statedotherwise,significancewas accepted at P -< 0.05. Results
and Discussion
Florida
indi-
mouth bass in neutral lakes, mean condition fac-
tors were significantlylower for both size groups We collected blood samples from 112 large- of fish in acidic clear lakes, and for larger fish in mouth bass that ranged in size from 193 to 627 acidic colored lakes (Table 2). Again relative to mm TL (90% of the fish were between 220 and fish in neutral lakes, growth was suppressedafter 425 mm TL). At eachlake, largemouthbasswere age 1 in both classesof acidic lakes (Table 2). ionoregulating under different chemical condi- Condition factors and growth were not signifitionsat the time of their capture(Table 1). Water cantly different between male and female fish. temperaturesduring the study ranged from 31øC Reduced condition factors and growth could be in Augustto 22øCin November (lakeswere sam~ attributed either to physiological stressassocipled randomly). Potentially stressfulchemical ated with acidity and heavy metals or to poorer conditionswere measuredin some of the study food suppliesin the acidic lakes (or to both); the lakes.In the acidic clear lakes,averagefield pH available data do not distinguish between these (littoral-water chemistryvaluesdid not differ sig- alternative causal factors. nificantly from open-watervalues in the study We found no significant changesin plasma lakes) rangedfrom 4.9 to 3.7 and averagealu- electrolyte or osmotic concentrations with minum concentrationsrangedfrom 0.01 to 0.16 changesin either fish size or sex. Several studies mg/L. Aluminum concentrationswere highestin have shownthat plasmaelectrolyte(Na* and C1-) Cue Lake and Long Lake (lakes with the lowest and osmotic concentrations are reduced in fish field pH) and were near values (0.2 mg/L) sug- exposedto acidic conditionsand that thesephysgestedto be toxic to fish (Schofieldand Trojnar iological changescan, if severe enough, lead to 1980; Baker 1982). Calcium concentrations in death (Wood and McDonald 1982). Among fish theselakes averagedlessthan 2 mg/L and none from the acidic Florida lakes, plasma Na* conof the lakes had color values above 5 platinum- centrationswere significantlylower than neutralcobalt units (PCU). In the acidic colored lakes, lake values for the colored lakes and four of the averagefield pH rangedfrom 4.1 to 4.6, but mean clear lakes (Table 3). Significantdifferencesin color values ranged from 20 to 60 PCU (Table plasma C1- and K* concentrationswere found,
1). Although pH values were low, the highest but they were not related to the different lake measured average aluminum concentration was
types. Plasma osmotic concentrations in fish from
426
CANFIELD ET AL.
T^BLE 1.--Mean limnological valuesfor 11 north-central Florida lakes sampledfor largemouth bass during 1983. pH
Temperature
Labor-
(øC)
atory
Lake
Date
Brooklyn Clear Cowpen Cue Long
Sep 9 Aug 25 Oct 12 Sep 14 Oct 10
31 30 26 29 26
5.2 3.7 3.9 3.7 4.0
Hourglass Ocean
Nov 11 Aug 10
22 31
4.5 4.4
Palestine
Oct 24
23
4.2
Color (Pt-Co
Field
Chlorophyll a
Total P
Total N
(mg/m3)
(mg/m3)
(mg/m3)
units)
•4cidic clear lakes
4.9 4.2 4.3 3.8 3.7
2.5 0 0 0 0
2.1 2.9 1.1 1.6 2.3
2.9 4.7 2.5 5.2 3.1
320 110 130 48 130
•4cidic colored lakes
4.6 4.1 4.3 Circumneutral
Alice Newnans Wauberg
Sep 16 Oct 11 Nov 14
26 25 23
6.9 6.4 7.4
6.9 6.8 7.3
20 60
4.3 3.2
10 21
670 290
40
2.5
13
300
73.9 61.5
1,100 63 210
lakes
40 80 50
122
1,100 1,500 1,800
the colored lakes were not significantlydifferent
concentrations
from those in fish from the neutral lakes (Table
by Florida largemouth bass. Canfield (1983) and Hendry and Brezonik (1984) estimated that a third to half of Florida's lakes are potentially sensitive to reductions in pH by acidic precipitation. Some lake acidification has occurred during the last 20 years because alkalinity has decreasedby more than 25 microequivalents/L and excess sulfate has increased by 16-34 microequivalents/L in some Trail Ridge soft-water lakes (Hendry and Brezonik 1984). The same number of largemouth bass populations, however, may not be susceptible to damage. Over 70% of Florida's lakes are colored (Canfield 1983). Plasma osmotic con-
3). Osmolalitiesof fishfrom the acidic clearlakes, however, were significantlylower except for Cue Lake.
In general, our results agree with previously reported laboratory studieson changesin plasma electrolyteand osmotic concentrationswith reductions in pH (Wood and McDonald 1982). Becauselittle nonlaboratory physiologicalwork has been done on fish subjectedto natural acid stress,we can not definitively determine if the measured reductions in plasma Na + and osmotic concentrations indicate physiological stress. Lower plasma electrolyte and osmotic concentrations could reflect a nonstressfulphysiological adaptationby largemouthbassto naturally acidic, low-conductivity waters. Acid-tolerant fish such as the white sucker Catostomus
commer-
soni are known to ionoregulate at low plasma
electrolyte and osmotic concentrations(Wilkes et al. 1981). For these fish, changesin plasma electrolyte and osmotic concentrationsare less severefor equivalent changesin pH than are the plasma changesfor acid-sensitive fish such as trout (Wood and McDonald 1982). The presence of largemouth bass in Florida lakes that have pHs equal to or below thosethat have apparently causeddamageto northern largemouth basspopulations (Harvey 1982; Rahel and Magnuson 1983) could be due to either low heavy metal
centrations
or to a difference in acid tolerance
in fish from our acidic colored lakes
were not significantlydifferent from values measured in fish from neutral lakes. Organic ligands also can complex aluminum, which reducestoxicity (Baker 1982). This may explain why highly acidic colored lakes like Ocean Pond (pH 4.1) continue to support a sustained sport fishery. Basedon this information, we suggestpH values in colored Florida
lakes could be reduced at least
to the levels existing in Ocean Pond and probably still support fish. If fish in Florida are susceptibleto damage by acidification, they most likely will be found in the naturally acidic, clear, soft-water, oligotrophic lakes. These lakes comprise about 10 to 15% (700 to 770 lakes) of Florida's lakes (Canfield
LARGEMOUTH
BASS PHYSIOLOGY
IN
ACIDIC
FLORIDA
427
LAKES
TABLE 1.--Extended.
Conduc-
Total
tivity
alkalinity
(•S/cm, 25øC)
(mg/L as CaCO3)
Ca (mg/L)
Brooklyn
27
I
1.2
0.5
Clear
49
0
1.5
0.9
Cowpen
56
0
1,9
1.0
Cue
44
0
0.56
Long
46
0
1.4
Lake
Mg (mg/L)
Na (rag/L)
K (mg/L)
AI (mg/L)
C1 (nag/L)
SO4 (rag/L)
3.7
0.1
0.01
5.2
6.0
4.0
0.3
0.04
6.9
7.5
5.9
0.7
0.06
8.9
10.7
0.7
2.7
0.2
0.13
6.8
6.5
1.0
4.4
0.3
0.16
6.6
9.8
Acidic clear lakes
Acidic colored lakes
Hourglass
21
0
0.36
0.4
2.5
0.2
0.01
3.9
0.7
Ocean Palestine
35 35
0 0
0.74 0.83
0.6 0.8
3.8 3.5
0.2 0.2
0.09 0.04
7.2 6.1
3.0 3.6
Alice Newhans
260 62
76 13
23 5.9
8.4 1.9
18 5.9
4.7 0.6
0.01 0.05
29 8.6
27.5 1.7
70
20
6.1
1.4
7.5
1.0
0
10.6
Circumneutral
Wauberg
lakes
0.1
year largemouth bass but no small bluegills Lepomis macrochirus or redear sunfish L. microbe reduced. Calcium concentrations, an imporlopbus,which were common in other acidic clear tant factor determining the physiological re- lakes. Blood samples from Cue Lake fish were sponse of fish to acid and heavy metal stress difficult to obtain and the majority of samples (Wood and McDonald 1982), are oftenlessthan were hemolyzed, a condition not found in fish 2 mg/L (Canfield 1981). Fish populationsin all blood samplesfrom other acidic or neutral lakes. theselakes, however, will not necessarilybe imThis condition could be due to sampling techmediately affectedby increasedacidification as nique or acidic conditions. Deformed otoliths fish reproduction occurred in all of our acidic occurredin four Cue Lake largemouth bass,which could indicate a disturbance in calcium metabclear lakes even with pH values below 4.5. In Cue Lake, we have collected young-of-the- olism (Wood and McDonald 1982). No de-
1983). Organic color is lacking; thus complexation of heavy metals with organicligandswould
T^BLE2.--Condition factors (K) and back-calculatedtotal lengths(TL, mm) at age of largemouthbassfrom 11 north-centralFlorida lakes. Valuesare means _+SE,' samplesizesare in parentheses;W is weight(g). Values alonga row withouta letterin commonare significantlydifferent(analysisof varianceand Duncan'smultiplerange test,'P -< 0.05). TL or age
Acidic clear lakes
Acidic coloredlakes
Circunaneutrallakes
Condition:K = l0 s W/TL 3 200-304
mm
1.08 _+ 0.01 a
(36) 305-425
mm
(19)
1.27 _+ 0.03 a
(19)
1.22 ñ 0.03 b 1.26 -+ 0.03 a
(13)
1.26 ñ 0.03 b
(13) 1.42 _+ 0.03 b
(18)
Total length (turn) at age
Agel Age2 Age3
180_+ 4a (58) 268_+ 7ab (26) 305_+ 7a (15)
167-+4a (28) 259-+4a (17) 300-+ 9a (7)
181 _+5a (32) 281 _+7b (20) 353_+ 8b (6)
428
CANFIELD ET AL.
TABLE3.--Plasma electrolyteand total osmoticconcentrations (means+ SE) in largemouthbassfrom 11 northcentralFlorida lakes. Valuesin a columnwithouta letter in commonare significantlydifferent(analysisof varianceand Duncang multiple-rangetest;P -< 0.05). Number of fish
Na + (rag/L)
Brooklyn
10
133 _+ 2 a
108 _+ 2 ab
3.3 _+0.1 ab
263 _+ 2 ab
Clear
10
129 _+ 2 a
105 _+ 2 abc
2.9 _+ 0.2 a
264 _+ 3 ab
Cowpen
10
135 _+ 3 ab
101 _+ 5 ab
4.6 _+0.3 d
268 _+ 5 abc
Cue
11
144 _+ 2cd
111 -+ 2bc
4.0 _+ 0.3 bcxt
275 _+ 4bcxt
Long
10
130 _+4a
101 _+ 3ab
3.6 _+0.2bc
261 _+6a
Lake
C1(rag/L)
K+ (rag/L)
Osmolarity (milliosmoles/kg)
Acidic clear lakes
Acidic colored lakes
Hourglass
8
141 _+ 3bc
99 _+ 3a
4.2 _+0.3bc
281 _+ 6d
Ocean
10
136 _+ 3ab
113 _+ 5c
3.7 _+ 0.2bc
283 _+ 5d
Palestine
12
141 _+ I bc
110 _+ 3abc
3.8 _+ 0.2bc
274 _+ 2bcxt
Circurnneutral
lakes
Alice Newhans
10 11
148 _+ 1 cd 145 _+ 2cxt
109 -+ 2abc 104 _+ 2abc
3.8 _+ 0.2bc 4.2 _+ 0.1 cd
278 _+ 3cd 277 _+ 3cxt
Wauberg
10
150 _+2d
110 _+ 5 abc
3.4 _+0.2ab
286 _+ 5 d
formed
otoliths
were collected
from fish in the
other lakes. We suggest,therefore, that the most sensitive acidic, clear, soft-water Florida lakes will be thoselakeswith pHs near 3.7 and calcium concentrationslessthan 1 mg/L (characteristics similar to those found at Cue Lake). Aluminum concentrationsin Florida lakes are presentlybelow toxic concentrations(Hendry and Brezonik 1984), but Baker (1984) demonstrated that aluminum concentrations increase rapidly to potentially toxic levels (0.25 to 0.30 mg/L) when
pH is loweredto 3.7. Until the factorscontrolling lake acidification and the biological response of lakes to acidification are understood, predictions
concerningthe future impact of acidic precipitation on Florida's lakesshouldbe regardedwith
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