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# Fisheries Session
Selenium-Induced Changes in Fish Populations of a Heated Reservoir
Gary P. Garrett, 

### Texas Parks and Wildlife Department, Junction StarRoute, Box

### 62, Ingram, 

### TX78025 Charles R. Inman, 

### Texas Parks and Wildlife Department, Route 10, Box 1043, Tyler, TX 

### 75707

Abstract: High selenium levels and changes in abundance and size distribution of fishes were discovered after reports of fish dying in Martin Creek Reservoir, Texas. The reservoir functions as a cooling source for a coal-fueled powerplant owned by Texas Utilities Generating Co. Analyses offish muscle tissue by the Texas Department of Health showed selenium concentrations ranging from 2.0 to 9.1 mg/kg. Cove rotenone sampling by the Texas Parks and Wildlife Departmentindicated biomass offishes, except common carp, Cyprinus carpio, was reduced 72%. Relative biomass of trophic groups was altered with planktivores changing from the largest to the smallest group, carnivores were initially reduced by nearly half, and omnivores more than doubled. Three years after the fish kills, planktivore biomass remained the lowest, carnivores had recovered to approximately 90% of their original biomass, and omnivores continued to dominate the community at 3 times their original abundance.

Proc. Annu. Conf. Southeast. Assoc. Fish and Wild!. Agencies 38:291-301

Selenium is 1 of several potentially toxic elements that have become

more prevalent in aquatic environments during the last decade. The increase in seleniumhasbeencausedprimarilybyburninglignite coal for production of electrical energy. This pollutant is significantly impacting aquatic life in ways that only recently have been fully realized. Toxic concentrations of selenium for fishes have been found to range from 2 to 80 mg/liter (Ellis et at. 1937, Weirand Hine 1970, Niimi and LaHam 1975, Cardwell et at. 1976) andfrom 0.3 to 42.4mg/literfor otherfreshwater animals (Environ. Protection Agency 1980). Toxicitywill varywith chemicalform ofselenium, species, life stage of the organism and duration of exposure. Environmental Protection Agency (1980) criterion for protection of freshwater aquatic life is a maximum concentration of 0.035 mg/liter. This amount is a 24-hour average for inorganic selenite 

### in water with concentration at no time exceeding 0.26 mg/liter.

1984 Proc. Annu. Coni. SEAFWA :oni. SEAFWA292 Garrett and Inman
Toxicity of selenium is due to inability ofenzyme systems to distinguish vari molecular structure of selenium from sulphur. When selenium is substituted and for sulphur in cellular constituents, metabolic problems arise due to greater reactivity and lower stability of selenium compounds (Stadtman 1974). Dr. One of the best documented cases of effects of selenium poisoning in an reta aquatic environment occurred at Belews Lake, North Carolina. Fish popUla­ 

### van tions dramatically declined in number over a 4-year period (1974-1977) and reproduction in all species except common carp, Cyprinuscarpio, was reduced 

### emF July to nearzero (Cumbie 1978, Cumbie and Van Horn 1978). This was attributed to high concentrations of selenium emanating from fiy ash sluice water from as" prio Belews CreekSteamStation. While the amount of selenium in the water never in d reached a lethal concentration, it was thought bioaccumulation through the bloc food chain was responsible for elevated levels found in fishes. Sandholm et al. ing (1973) demonstrated selenium could accumulate in fishes via the food chain. Bioaccumulationhas been shown to be directly proportional to the concentra­ hOll tion in water and sediment (Fowler andBenayoun 1976) with selenium enter­ rote Fisl1 ing thefood chainprimarilythrough phytoplankton. Concentrationsin skeletal 

### 25-1 muscles ofthose species examinedranged from 5 to 50mg/kg. Levels in fishes dud from an unaffected reservoir, Lake Norman, North Carolina, averaged only 0.7 mg/kg.**sep~** size Thispaperfo<?uses onfish community changes that occurred after a coalfueled power plant released selenium-rich water into Martin Creek Reservoir, wer, spec Texas. This type ofsituation is likely to be a recurrent problem in power plant reservoirs and itis hoped this study will aid future efforts to document cause sistc and effect. The authors express appreciation to the Inland Fisheries personnel ofthe Texas Parks andWildlife Departmentwho assisted with the many field collec­ 

### Ret tions and editingthispaper andtoBillL. Minsonfor his assistance in preparation ofthefigures. Tw, frOl 

### Description of StUdy Area and Martin Creek Reservoir covers 2,000 ha in Rusk County, Texas. The con por watershed is composed ofrolling hills with mixed pine and hardwood forests. The reservoir was constructed in 1974 on Martin Creek, a tributary of the the Sabine River, by Texas Utilities Generating Co. as a cooling reservoir for its Wil steam-electric power plant. the
exa 

### Methods of

. An extensive investigation of a slow die-off of fishes at Martin Creek (Tc Reservoir began in July 1979. Possible causes for the die-offwere investigated 19' by the Texas Parks and Wildlife Department, Texas Department of Health, and the Texas Department of Water Resources. These included monitoring wo

198 1984Proc. Annu. Conf.SEAFWAs to distinguish
II is substituted due to greater
lD 1974). poisoning in an
a. Fish populan4-1977) and io, was reduced
5was attributed lice water from the water never
on through the Sandholm et al. the food chain.

,the concentraselenium entertions in skeletal Levels in fishes

averaged only**~ed** after a coalreek Reservoir,

Iin power plant iocument cause )ersonnel ofthe my field collecmce in preparatty, Texas. The rdwood forests. :ributary of the reservoir for its

t Martin Creek

ere investigated nent of Health, ded monitoring

I. Coni. SEAFWA Selenium-Induced Population Changes 293

various physicochemical parameters and testing for heavy metals, metalloids and pesticidesin water, sediment, and organic tissues. Two consultants, Dr. Owen Lind (limnologist, Baylor University) and Dr. Elsie Sorensen (environmental toxicologist, University of Texas) were retained by the Texas Parks and Wildlife Department to provide expertise in various facets of the investigation. To detect changes in the fish populations, cove rotenone sampling was employed for 3 consecutive years. These collections were conducted each July, 1979 to 1981, in the same areas and by the same personnel and manner
as were employed during a previous management survey in July 1977, 1 year prior to initiation ofthe fish die-off. Three coves, totaling 1.5 ha, were located in different sections ofthe reservoir within the main waterflow pattern. Nylon block-offnets (16-mm mesh) were used to prevent fish from entering orleaving the sampling area. The nets were installed after sundown (2200-0100 hours) and prior to application of rotenone the following morning. Liquid rotenone (5%) was applied at a rate of 3 mg/liter to ensure a total kill. Fishes were collected for 2 days and separated into species and then into 25-mm size groups. All fish species were counted and weighed by size groups duringthefirst dayofcollection. Duringtheseconddayofrecovery, fishes were separated by species and size groups and counted; weights were taken only for size groups of species not obtained during the first-day collections. Results

were reported as number and kilogram per hectare by size group for each· species. For some comparisons, fishes were grouped by trophic level. These consisted of top carnivores, planktivores, and omnivores (Table 1).



### Results and Discussion

A slow die-off of fishes began in Martin Creek Reservoir in July 1978. Two months earlier, the utility company had begun unauthorized discharges from 2fly-ash pondsinto the reservoir. Fly-ashis aby-product ofburning coal and often has a high selenium content. In September 1978, chemical analyses conductedbytheTexasDepartmentofWaterResources ofwater in the fly-ash ponds showed selenium levels of 2.2 to 2.7 mg/liter. Shoreline counts ofdead fishes were unreliable due to the slow nature of the die-off and delay or failure in reporting fish kills to the Texas Parks and Wildlife Department. Autopsies conducted during the die-off did not reveal thepresenceofparasitesorbacteriain epidemicproportions. However, internal examination revealed enlarged kidneys and hemorrhaging in some specimens. Analyses offish muscle tissue from thereservoir bytheTexas Department of Health revealed selenium concentrations ranging from 2.0 to 9.1 mg/kg (Table 2). This is considerably greater than 0.2 mg/kg recorded in February 1979 for largemouth bass, Micropterus salmoides, in uncontaminated BellwoodReservoirin adjacent SmithCounty. Concentrations ofmercury, copper,

1984 Proe. Annu. Coni.SEAFWA294 Ga"ett and Inman

Table 1. Trophiclevel groupings offishes from Martin Creek Reservoir, Texas, 1977-1981.

Top carnivores Omnivores spotted gar (Lepisosteusoculatus) bowfin (Amia calva) blue catfish (lctalurusfurcatus)1l channel catfish (I.punctatus) Il flathead catfish (Pylodictis otivaris)lI. green sunfish (Lepomis cyanellus)b warmouth (L. gulosus)b largemouthbass (Micropterussalmoides)b white crappie (Pomoxisannularis)b black crappie (P. nigromaculatus)b Planktivores gizzard shad (Dorosoma cepedianum) threadfin shad (D. petenense) golden shiner (Notemigonus crysoleucas) red shiner (Notropis lutrensis) blacktail shiner (N. venustus) inland silversides (Menidia beryllina) commoncarp (Cyprinus carpio) spotted sucker (Minytrema melanops) lake chubsucker (Erimyzon sucetta) blackbullhead (lctaluras melas) yellow bullhead (I. natatis) tadpole madtom (Notorusgyrinus) blue catfish (lctalurusfurcatus)c channelcatfish (I.punctatus)c flathead catfish (Pylodictis olivaris)c green sunfish (Lepomiscyanellus)d warmouth (L. gulosus)d bluegill (L. macrochirus) longear sunfish (L. megalotis) redear sunfish (L. microlophus) spotted sunfish (L.punctatus) bantamsunfish (L. symmetricus) largemouthbass (Micropterussalmoides)d white crappie (Pomoxis annularis)d black crappie (P. nigromaculatus)d

• TL2:: 368 mm. b TL2: 114mm.

e TL 367 mm. dTL;;:a 113 nun.


### zinc, manganese, and chromium were found to be similar in the 2 reservoirs. Selenium in muscle tissue of largemouth bass from 3 other coal-fueled power plant reservoirs in Texas averaged only 0.8 mg/kg. In an unpublished report, Lind stated that the high concentration of selenium in surficial sediments (up to 14 mg/kg in 1982) was indicative of a recent addition and that this pollutant should continue to impact the Martin CreekReservoir ecosystemfor years to come. Thelatter assessment was based uponthelowflushing ratefor the reservoir and thepresence ofthe Asian clam, Corbicula 

### sp., whose deep-burrowing actions could delay removal by sedimentary processes. Three years after the die-off, Sorensen et al. (l982a) 

### found selenium concentrations ashigh as 6mg/kgin skeletalmuscle ofredear sunfish, Lepomis microlophus, 

### at Martin Creek Reservoir. This is well above the 2-mg/kg level recommended by the National Health and Medical Research Council of Australia as a maximum in seafoods consumed by humans (Bebbington et al. 1977). Sorensenhas published extensively onphysiological maladies ofredear andgreensunfish, L.cyanellus,

### exposedto seleniuminMartinCreekReservoir. Theseinclude reduced hematocrits, lower hemoglobin concentrations, changes inleukocyte distribution, small, irregularly shaped erythrocytes, reduced mean corpuscular volume, reduced mean corpuscular hemoglobin concentration

1984Proc.Annu. Coni. SEAFWAI 2/82 rvoir, Texas,

lrpio)
I melanops)
'lsucetta) 'lelas) gyrinus) atus)c IS)C olivaris)c mellus)d Selenium-Induced Population Changes 295

Table 2. Selenium concentration (mg/kg) in fish muscle tissues, Martin Creek Reservoir, Texas, from analyses conducted by Texas Department of Health. Sample sizes>I are given in parentheses.

Species 2/79 4/79 7/79 3/80 4/81 Spotted gar 2.0 3.0 Gizzard shad 7.0 5.6 7.3 5.3 (2) 5.1 (4) 2.9 (9) Common carp 9.1 (2) 4.6 4.6 5.6 (2) 3.6 (4) Channelcatfish 3.2 2.7 (7) 4.6 (3) 2.8 (8) 3.3 2.7 Largemouthbass 7.1 8.3 (3) 6.2 (8) 3.8 (14) Redear sunfish 5.6 (8) 4.4 (4) Bluegill 6.8 (5) 5.8 (8) 3.4 (5) Longear sunfish 5.1 (6) Blackcrappie 6.8 (2) 5.4

tis) 7hus) us) tricus) ?rus salmoides)d nularis)d ;ulatus)d

2 reservoirs. -fueled power

lcentration of ndicative of a lct the Martin ent was based le Asian clam, lOVal by sedilund selenium lfish, Lepomis 2-mg/kg level h Council of lbington et al. ldies ofredear ;:ekReservoir. tions, changes reduced mean concentration

Conf.SEAFWA (Sorensen and Bauer 1983), kidneys with proliferative glomerulonephritis, hematuria and necrosis of convoluted tubule cells (Sorensen et al. 1982a, 1982b, 1983),central necrosis and increased numbers of phagocytotic reticuloendothelial cells in hepatic tissue (Sorensen et al. 1982, 1983), reduced hepatopancreas-weight-to-body-weight ratio (Sorensen and Bauer 1984), hypertrophy of exocrine pancreas tissue (Sorensen et al. 1983), vacuolated and thickened gill lamellae and ovaries with an increased number of atretic follicles (Sorensen et al. 1982a). Following the die-offin 1978, fish community structure was altered considerably. Total fish biomass was reduced by 11% in 1979; however, this percentage is understated since 154 common carp accounted for 70% of the total weight recovered. Common carp have been shown to be relatively resistant to selenium poisoning (Huckabee and Griffith 1974). Without common carp in either the 1977 or 1979 samples, the standing crop was reduced 72%. The greatest declines in biomass were sustained by planktivorous and carnivorous fishes while omnivores increased (Fig. 1). Planktivores changed from the largest to the smallest group, carnivores were reduced by nearly half, andomnivoresbecamethe largest group at4 times their original size. By 1981, planktivore biomass remained the lowest, carnivores had recovered to approximately 90% of their original biomass, and omnivores continued to dominate the community at 3 times their original abundance. Two of the more prominent planktivores in Martin Creek Reservoir

were gizzard shad, Dorosoma cepedianum, and threadfin shad, D. petenense

. Gizzard shad density was reducedfrom 889.7/hain 1977to 181.6/hain 1979 and had recovered to only 263.8/ha by 1981. Threadfin shad numbers were also reduced (l30/ha to 6.4/ha),but greatly recovered in 1980 (271.5/ha). The deleterious effects of selenium may have also influenced interspecific competition in the above instance. It is conceivable that a species could actually realize a net benefit from selenium contamination if selenium affected a competitorto an equal or greater degree and the effects of competition were more detrimental to this species than the effects of selenium. Both

1984 Proc. Annu. Coni. SEAFWA__**,",,,7,",,_:C--,:,,,,,~~;;~;~~","~':"'-=;-:~~:;"!"'~_"_,,,,?!--"'<- ~-** **'_~-~~e--~~'~~'= _:~_:':**  __:**."~,:"":~~~.,.:",_~~~.,,.......-,~-~_-,,--** .=---=-=

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Figure 2. Biomass of harvestable-size sport fishes from cove rotenone sampling, Martin Creek Reservoir, Texas, July, 1977, 1979, 1980, and 1981.

1984 Proc.Annu.Coni. SEAFWA 18

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LENGTH GROUP ( mm TL) Figure 3. Length-frequency distribution of largemouth bass from cove rotenone sampling, Martin Creek Reservoir, Texas, July, 1977, 1979, 1980, and 1981.

1984Proc. Annu. Conf. SEAFWA thread release than b 1981, Total: level ( C channl increa: I-year tolerar and V; sensiti A 1980, passed indical the**m~** Severa The d. well a1 (angle contar V by 191 the 101 surpri: time ( (Cum! I discha 1981 1979 : in nUl Redu( substa densit I years systen drastil plank! relati( tainly

1984PSelenium-Induced Population Changes 299



### threadfin and gizzard shad suffered a numerical decrease after the selenium release; however, in 1980 threadfin shad were actually in greater abundance than before the discharge. Gizzard shad did not show signs of recovery until 1981, at which time the threadfin shad began to decline again (to 88.4/ha). Total shad density in 1981, however, remained below the 1977 pre-selenium level (1,019.7/hain 1977 and 352.2/ha 

### in 1981). One of the more important carnivores in Martin Creek Reservoir is the channel catfish, Ictalurus punctatus. 

### Biomass of adult channel catfish, after increasing in 1979, fell below the 1977 level in 1980 and 1981 (Fig. 2). The I-year delay in 

### biomass reduction suggests that adults may have had a higher tolerance to selenium than some of the other species in this study. Cumbie and Van Horn (1978) reported that adult channel catfish appeared to be less sensitive to selenium than are centrarchids. Adult largemouthbass biomass was reduced in 1979, began increasing by 1980, and by 1981, biomass of harvestable-size largemouth bass had far surpassed the 1977 pre-selenium level (Fig. 2). Length-frequency distribution indicated these fish were probably spawned in 1979 (Fig. 3) accounting for the majority of the yearlings (178-229 mm TL) in 1980 and adults in 1981. Several factors may have contributed to enhanced survival of this year class. The die-off in 1978 probably reduced inter- and intraspecific competition as well as predation at a critical time in their life. Additionally, human predation (angler harvest) was certainly reduced due to publicity concerning selenium contamination in

### the reservoir. While conditions for harvestable largemouth bass may have improved by 1981, reproductive success remained detrimentally affected as indicated by the low numbers ofyoung-of-the-year in 1979 and 1980 (Fig. 3). This is not surprising in light of evidence that selenium accumulates in organisms over time (Kaiser et al. 1979) and has a detrimental effect on fish reproduction (Cumbie 1978, Cumbie and Van Horn 1978). Biomass of sunfishes, Lepomis 

### spp., was reduced following the selenium discharge with fewer quality**(~152** 

### mm TL) sunfishes in the 1979, 1980, and 1981 collections (Fig. 2). Population density, however, increased during the 1979 spawning season and continued the following year with a 62% 

### increase in number over the 1977 level (4,038/ha in 1977 and 6,511/ha in 1980). Reduced predation, due to a lower number of carnivores, probably permitted substantial survival of young sunfishes resulting in an increase in population density and an undesirable population balance. If

### no additional selenium were added to 

### Martin Creek Reservoir, many years might still be required before the existing contamination of this ecosystem is reduced to natural levels. So far, the contamination seems to have drastically altered the fish community structure. The relative abundance of planktivores versus omnivores remains reversed from the pre-contamination
e rotenone relationship. The increase in available forage (e.g., small sunfishes) is cer1981. 

### tainly beneficial to piscivores, but since this increase was probably due to

.SEAFWA 1984Proc. Annu.Con£. SEAFWA34

vii 300 Garrett and Inman

reducedpredation and competition, it may be short-lived. Numbers of qualitysize channel catfish and sunfishes weregreatlyreduced and haveremained low. While there are now more adult largemouth bass present, reproduction remains detrimentally affected. Even if selenium concentrations eventually return to an acceptable level, fish community structure in this reservoir may not necessarily return to pre-contamination proportions. Cooperation between state agencies and private consultants enabled the Texas Parks and Wildlife Department to observe selenium levels in the reservoir and effect a management program to reduce selenium releases and improve conditions in the lake. The department is now involved in a long-term program of monitoring selenium in sediments and fish tissue, monitoring the fish community, and restocking certain fish species in an attempt to restore this system.

Literature Cited Bebbington, G. M., N. J. Mackay, R. Chvojka, R. J. Williams, A. Dunn, and E. H. Auty. 1977. Heavy metals, selenium and arsenic in nine species of Australian commercial fish. Australian J. Mar. and Freshwater Res. 28:277-286. Cardwell, R. D., D. G. Foreman,T. R. Payne, and D. J. Wilbur. 1976. Acute toxicity ofselenium dioxide to freshwater fishes. Arch. Environ. Contam. and ToxicoI. 4: 129-144. Cumbie, P. M. 1978. Belews Lake environmental study reports: selenium and arsenic accumulation. Duke Power Co., Tech. Rep. Series No. 78-04, Charlotte, N.C. and S. L. Van Horn. 1978. Selenium accumulation associated with fish mortality and reproductive failure. Proc. Annu. Conf. Southeast. Assoc. Fish andWildI. Agencies. 32:612-624. Ellis, M. M., H. L. Motley, M. D. Ellis, and R. O. Jones. 1937. Selenium poisoning in fishes. Proc. Soc. for Exp. BioI. and Med. 36:519-522. Environmental Protection Agency. 1980. Ambient water quality criteria for selenium. Environ. Protection Agency, 440, 5-80-0/0. Washington, D.C. Fowler, S. W. and G. Benayoun. 1976. Influence of environmental factors on selenium flux in two marine invertebrates. Mar. BioI. 37:59-68. Huckabee, J. W. and N. A. Griffith. 1974. Toxicity of mercury and selenium to the eggs of carp (Cyprinus carpio). Trans. Am. Fish. Soc. 103:822-824. Kaiser, I. I., P. A. Young, and J. D. Johnson. 1979. Chronic exposure of trout to waters with naturally high selenium levels: effects on transfer RNA methylation. J. Fish. Res. Bd. Can. 36:689-694. Niimi, A. J. and Q. M. LaHam. 1975. Selenium**to~icity** on the early life stages of zebrafish (Brachydanio rerio). J. Fish. Res. Bd. Can. 32:803-806. Sandholm, M., H. E. Oksanen, and L. Pesonen. 1973. Uptake of selenium by aquatic organisms. Limnol. and Oceanogr. 18:496-499. Sorensen, E. M. B. and T. L. Bauer. 1983. Hematological dyscrasia in teleosts chronically exposed to selenium-laden effluent. Arch. Environ. Contam. and Toxicol. 12: 135-141.

1984Proc. Annu. Conf. SEAFWA an

cy

ex
fis**Stadtm~** Weir, P tic

1984PrNumbers ofqualitydhaveremainedlow.**~nt,** reproduction re­ 'ations eventually rehis reservoir may not

lsultants enabled the

m levels in the reser­
.um releases and im­ 'olved in a long-term issue, monitoring the

m attempt to restore

s, A. Dunn, and E. H.
e species of Australian

s. 28:277-286.**lr~** 1976. Acute toxicity Contam. and ToxicoI.

:eports: selenium and ries No. 78-04, Charn associated with fish Southeast. Assoc. Fish

17. Selenium poisoning 22. lality criteria for sele­ lshington, D.C. ironmental factors on 7:59-68. ry and selenium to the

103:822-824.
c exposure of trout to ransfer RNA methylathe early life stages of Selenium-Induced Population Changes 301

--- and

. 1984. A correlation between selenium accumulation in sunfish and changes in condition factor and organ weight. Environ. Pollut. (Series A) 34:357-366.

---. ---., J. S. Bell, and C. W. Harlan. 1982a. Selenium accumulation and cytotoxicity in teleosts following chronic environmental exposure. BuI. Environ. Contam. and Toxicol. 29:688-696.

---,J. S. Bell, and C. W. Harlan. 1983. Histopathological changes in seleniumexposed fish. The Am. J. Forensic Med. and Pathol. 4:111-123.

---, C. W. Harlan, and J. S. Bell. 1982b. Renal changes in selenium-exposed fish. The Am. J. Forensic Med. and Pathol. 3:123-129. Stadtman, T. C. 1974. Selenium biochemistry. Science. 183:915-922. Weir, P. A. and C. H. Hine. 1970. Effects of various metals on behavior of conditionedgoldfish. Arch. Environ. Health. 20:45-51.

2:803-806. ptake of selenium by

I dyscrasia in teleosts Environ. Contam. and

.Annu. Conf. SEAFWA 1984 Proc. Annu. Conf. SEAFWA