Roger L. Herman

Pathological effects of orally administered estradiol to rainbow trout

Abstract Mortality was high in an experimental group of rainbow trout ( Salmo gairdneri ) fed estradiol as part of a sex reversal study. Pathology included hypertrophy of the kidneys and liver and heavy accumulations of presumptive vitellogenin.

Acute toxicity of tributyltin to selected Chesapeake Bay fish and invertebrates

Abstract Acute tributyltin (TBT) toxicity experiments were conducted on selected Chesapeake Bay biota. Four invertebrate and five fish species were evaluated. Tests were conducted using continuous-flow conditions and TBT concentrations were measured every 24 h in test containers. Test solutions were generally within 10–15% of the predicted concentrations. Estuarine copepods were very sensitive to TBT. A 72-h LC 50 of 0.6 μg 1 −1 TBT was reported for Eurytemora affinis; Acartia tonsa had a 48-h LC 50 of 1.1 μg 1 −1 TBT. The most resistant invertebrate tested was the grass shrimp, Palaemonetes sp. (96-h LC 50 > 31 μg 1 −1 TBT). The most sensitive fish species tested were larval inland silversides ( Menidia beryllina ), (96-h LC 50 = 3.0 μg 1 −1 TBT) and juvenile Atlantic menhaden ( Brevoortia tyrannus ), (96-h LC 50 = 4.5 μg 1 −1 TBT). Mummichogs ( Fundulus heteroclitus ) and sheepshead minnow ( Cyprinodon variegatus ), (96-h LC 50 = 23.8 and 25.9 μg 1 −1 TBT, respectively) were the most resistant fish species tested. Concentrations of TBT exceeding the LC 50 values reported for both copepod species have been found in the water column from marinas in northern Chesapeake Bay. Acute TBT toxicity data and its application to environmental concentrations in Chesapeake Bay are discussed.

Hatchery efficacy trials with chloramine-T for control of bacterial gill disease

Abstract Three hatchery trials were carried out to determine the efficacy of chloramine-T for the control of bacterial gill disease in rainbow trout Oncorhynchus mykiss, ranging in weight from 2.5 to 54 g. In each trial, we used a single flow-through treatment of 8.5 mg chloramine-T/L. The single treatment provided effective control in all three trials; however, results were best when treatment was begun in the early stages of an outbreak. A second or third treatment may be required if an outbreak is in an advanced stage or if fish are under stress.

Pathology Caused by the Bacterium Edwardsiella tarda in Striped Bass

Abstract Edwardsiella tarda was isolated from moribund age-0 hatchery-reared striped bass Morone saxatilis for the first time. Pathogenicity was confirmed by contact infection. Characteristic histopathology consisted of epithelial hyperplasia and necrosis associated with the lateral line canals, and abscess formation in the anterior kidney and other internal organs.

In situ striped bass (Morone saxatilis) contaminant and water quality studies in the Potomac River

Abstract The objectives of this study were to evaluate survival of striped bass (Morone saxatilis) prolarvae and yearlings in the Potomac River by using in situ test chambers; correlate survival of both striped bass life stages with the presence of water quality conditions, inorganic contaminants, and organic contaminants and conduct histological examinations of surviving yearling striped bass. Survival of striped bass prolarvae ranged from 4.5–22.5% at three field locations during three 96-h experiments; control survival was ≥81%. Yearling survival ranged from 0–77.5% at three river stations during two 7-d experiments; highest mortality occurred at the upriver station. Control survival was 100%. Poor survival of striped bass prolarvae was likely related to the presence of inorganic contaminants (monomeric aluminum, cadmium, and copper) acting singly or synergistically and sudden decreases in water temperature (

Chronic toxicity of tributyltin to Chesapeake Bay biota

Chronic tributyltin toxicity experiments were conducted with the following Chesapeake Bay organisms: amphipod, Gammarus sp.; juvenile Atlantic menhaden, Brevoortia tyrannus and larval inland silverside, Menidia beryllina. TBT concentrations ranging from 29 to 579 ng L−1 did not significantly affect survival of the benthic amphipod, Gammarus sp. after 24-d exposures. The weight of Gammarus exposed to control conditions was 2.8 times greater than the weight of these test organisms exposed to 579 ng L−1 TBT. Twenty-eight day exposures to TBT concentrations of 93 and 490 ng L−1 did not significantly affect survival of juvenile B. tyrannus or larval M. beryllina. Histological examinations of B. tyrannus did not demonstrate absolute effects resulting from TBT exposure due to extensive variation between individuals. Various morphometric measurements of M. beryllina after TBT exposure did not demonstrate significant effects. However, significant reductions in growth were reported for M. beryllina at both TBT concentrations. Environmental concentrations of TBT in Chesapeake Bay and possible effects on the above biota are discussed.

Histopathology associated with pyridoxine deficiency in Atlantic salmon (Salmo salar)

Abstract Fingerling Atlantic salmon ( Salmo solar ) fed a production diet deficient in pyridoxine showed several significant effects: increased mortality; behavioral changes; degenerative changes in kidneys, ovaries, and liver; a paucity of thyroid colloid; and hyperplasia of renal hematopoietic tissue. Changes in nerve tissue were equivocal.

Development of a practical diet for juvenile striped bass

Abstract We formulated four diets that simulated the amino acid profiles of eggs of striped bass Morone saxatilis, carcasses of larval striped bass, eggs of rainbow trout Oncorhynchus mykiss, or nauplii of Artemia salina; a fifth diet contained a high concentration (33.6%) of shrimp meal. These diets were fed to juvenile striped bass for 14 weeks. Striped bass grew best when fed diets with an amino acid pattern that simulated the patterns of rainbow trout eggs or Artemia salina. Fish fed these two diets grew as well as, and had carcass compositions and protein efficiency ratios similar to those of, control fish fed the federally specified ASD2-30 salmon diet. No histological or morphological abnormalities were noted. These two diets, which have potentially lower production costs and contain slightly less protein than ASD2-30, may be used as prototype diets specifically for striped bass. Through further minor refinements, the diets could be used in production hatcheries.

Communications: Effects of Orally Administered Steroids on Lake Trout and Atlantic Salmon

Abstract Lake trout (Salvelinus namaycush) and Atlantic salmon (Salmo salar) fed 30 mg β-estradiol/kg of feed for 100 d from first feeding had liver and kidney pathology similar to but much less severe than that previously reported for rainbow trout (Oncorhynchus mykiss). Mortality was not affected. Both lake trout and Atlantic salmon treated with estradiol weighed significantly less than control fish at the end of the treatment period and at 200 d posttreatment. Testosterone-treated fish of both species weighed less than control fish at the end of the treatment period. By day 200 posttreatment, testosterone-treated and untreated lake trout weighed the same, but testosterone-treated Atlantic salmon were heavier than control fish. Estradiol treatment produced an all-female population of Atlantic salmon but not of lake trout. Testosterone at 5 mg/kg feed increased the ratio of males to females in both species.

Liver lesions in winter flounder (Pseudopleuronectes americanus) from Jamaica Bay, New York: Indications of environmental degradation

Liver sections of winter flounder (Pseudopleuronectes americanus) collected from Jamaica Bay and Shinnecock Bay, New York, in 1989, were examined microscopically to determine the pervasiveness of liver lesions observed previously in Jamaica Bay winter flounder. Neoplastic lesions were not detected in fish from Jamaica Bay or the Shinnecock Bay reference site. Twenty-two percent of Jamaica Bay winter flounder examined (n=103) had unusual vacuolization of hepatocytes and biliary pre-ductal and ductal cells (referred to hereafter as the vacuolated cell lesion). The lesion, identical to that found in 25% of Jamaica Bay winter flounder examined in 1988, has previously been identified in fishes taken from highly polluted regions of the Atlantic coast (e.g., Boston Harbor, Massachusetts, and Black Rock Harbor, Connecticut). Prevalence of the vacuolated cell lesion in winter flounder from Jamaica Bay was significantly greater (p<0.0001) than in 102 specimens collected from Shinnecock Bay. Current scientific literature indicates vacuolated hepatocytes and cholangiocytes are chronically injured and that the extent of their deformity is consistent with the action of a hepatotoxicant. The high prevalence of vacuolated hepatocytes in Jamaica Bay winter flounder and absence of the lesion in flounder from reference sites strongly supports the hypothesis that this impairment is a manifestation of a toxic condition in at least some portions of Jamaica Bay.