Sheepshead

Sheepshead minnow Cyprinodon variegates) DMTC 96-h LC50 >1000 >1000 Boeri et al. (1995)... 

Sheepshead minnow (Cyprinodon variegatus) DBTC 191-day NOEC (survival, growth, and fecundity) 0.45 0.45 Elf Atochem NA (1992)... 

Boeri RL, Kowalski PL, Ward TJ (1995) Acute toxicity of the water accommodated fraotion (WAF) of alkyltin MAto the sheepshead minnow, Cyprinodon variegatus. T.R. Wilbury Laboratories, Ino., Marblehead, MA, 10 November (Study No. 863-MO). 

Elf Atochem NA (1992) Life-cycie toxicity of dibutyitin dichtoride to the sheepshead minnow in a fiow-through system. Sponsored by the Consortium of Tributyitin Manufacturers (Atochem North America, Inc., King of Prussia, PA, and Sherex Chemical Co., Inc., Dublin, OH). Study conducted by Gulf Coast Research Laboratories, Ocean Springs, MS, 27 October (Contract No. ES-7339, Subtask 2D). 

Sheepshead minnow, Cyprinodon variegatus 1400 LC50 (96 h), juveniles 4... 

Sheepshead minnow, Cyprinodon variegatus 0.18-1.0 Maximum BCFs after 167 days were 1600 in muscle, 3900 in viscera, 52,000 in liver no adverse effects on growth or reproduction 20... 

Parrish, P.R., E.E. Dyar, M.A. Lindberg, C.M. Shanika, and J.M. Enos. 1977. Chronic Toxicity of Methoxy-chlor, Malathion, and Carbofuran to Sheepshead Minnows (Cyprinodon variegatus). U.S. Environ. Protection Agen. Rep. 36 pp. 

Cripe, G.M., D J. Hansen, S.F. Macauley, and J. Forester. 1986. Effects of diet quantity on sheepshead minnows (Cyprinodon variegatus) during early fife-stage exposures to chlorpyrifos. Pages 450-46 in T.M. Poston and R. Purdy (eds.). Aquatic toxicology and environmental fate ninth symposium. ASTM Spec. Tech. Publ. 921, American Society for Testing and Materials, Philadelphia, PA. 

Sheepshead minnow, Cyprinodon variegatus 0.47 Reduced fecundity 3... 

Goodman, L.R., D.J. Hansen, D.L. Coppage, J.C. Moore, and E. Matthews. 1979. Diazinon chronic toxicity to, and brain acetylcholinesterase inhibition in, the sheepshead minnow, Cyprinodon variegatus. Trans. Amer. Fish. Soc. 108 479-488. 

Hansen, D.J., L.R. Goodman, J.C. Moore, and P.K. Higdon. 1983. Effects of the synthetic pyrethroids AC 222, 705, permethrin and fenvalerate on sheepshead minnows in early life stage toxicity tests. Environ. Toxicol. Chem. 2 251-258. 

In this report we compare several properties of hepatic microsomal AHH activity in control and DBA-treated little skates (including metabolic profiles obtained from c-benzo(a)pyrene as elucidated by high pressure liquid chromatography [HPLC]), we describe the partial purification of two different forms of cytochrome P-450 (cytochrome P-448 and cytochrome P-451) from hepatic microsomes of DBA-pretreated little skates and we report polycyclic hydrocarbon-like induction in large numbers of winter flounder assayed in Maine during June, July, and August, which was quite different than data obtained with sheepshead examined in Florida during the same period. 

In spite of these limitations there seems little doubt that induction of the hepatic MFO system in certain fish can indicate the presence of selected toxic chemicals (to fish and humans) in both freshwater and marine environments. For this reason we have been studying various aspects of this question for the last few years in freshly captured fish (winter flounder and little skate in Maine and the sheepshead in Florida) and in fish induced by polycyclic hydrocarbon administration. 

One of our more interesting observations is illustrated in Table III. The administration of DBA to winter flounder increased hepatic microsomal AHH and 7-ethoxyresorufin deethylase activities as expected, and AHH activity was strongly inhibited in the DBA-treated flounder by 10" M a-naphthoflavone as we have previously reported for both little skate (4) and sheepshead (9). However, the presence of high AHH and 7-ethoxyresorufin deethylase activities in one control flounder, and the inhibition of AHH activity by a-naphthoflavone in this animal suggested that the hepatic microsomal MFO system of this fish was already induced. 

Similar studies conducted at our Florida laboratory with the sheepshead have produced quantitatively different results (James, M. 0., unpublished data). Of twenty-nine sheepshead assayed in June-August over two years, only four have had partially induced hepatic MFO systems. 

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