Acknowledgments 



John S. Pearse, Ronald Jameson, and an 

 anonymous reviewer provided advice and critical 

 discussion for this study. Christopher Harrold 

 gave technical and diving help. We thank the staff 

 at Hopkins Marine Station of Stanford University 

 for their assistance. This work was partially 

 funded by the U.S. Fish and Wildlife Service. 



Literature Cited 



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ANSON H. HINES 



Chesapeake Bay Center for Environmental Studies 



Smithsonian Institution 



P.O. Box 28, Edgewater, MD 21037 



Thomas r. loughlin 



Office of Marine Mammals and Endangered Species 

 National Marine Fisheries Service, NOAA 

 Washington, D C 20235 



EFFECT OF ZINC ON FIN REGENERATION IN 



THE MUMMICHOG, FUP^DULUS HETEROCLITVS, 



AND ITS INTERACTION WITH 



METHYLMERCURY 



Methylmercury has been found to retard fin re- 

 generation in the marsh killifish, Fundulus 

 confluentus, and striped mullet, Mugil cephalus 

 (Weis and Weis 1978). In F. confluentus the re- 

 tarding effect of methylmercury was masked in 

 water of reduced salinity (9%o). Cadmium, which 

 also retarded fin regeneration in killifish (Weis 

 and Weis 1976), interacted antagonistically with 

 methylmercury so that fish exposed simultane- 

 ously to the two metals exhibited growth rates 

 comparable to controls (Weis and Weis 1978). 



This paper reports on the effects of zinc on re- 

 generation in the mummichog, F. heteroclitus , 

 and the effects of combinations of methylmercury 

 and zinc on this process. 



Methods 



Fish were collected by seining in the vicinity of 

 Montauk, N.Y. The lower portion of each caudal 

 fin was amputated with a scalpel, and approxi- 

 mately 15 fish were placed in each of several all- 

 glass aquaria with 10 1 of 30%o salinity water. The 

 temperature was 20°-22° C and the photoperiod 

 was 14 h light/10 h darkness. Fish were fed com- 

 merical fish food and live grass shrimp, Palaemo- 

 netes pugio. Tanks were dosed with methylmer- 

 curic chloride (I.C.N. Pharmaceuticals, Plainview, 

 N.Y.i) from a 0.1 mg/ml stock solution in 

 0.2% NaHCOg to yield a final calculated concen- 

 tration of 0.050 or 0.025 ppm depending on the 

 experiment, and/or with ZnClg (Reagent Grade, 

 Fisher Scientific) from a 1.0 mg/ml stock solution 

 to yield calculated concentrations of 1.0, 3.0, or 

 10.0 ppm. Aquaria were washed, refilled, and re- 

 dosed after 2, 4, 7, 9, and 11 days. Regenerating 

 fins were measured with a calibrated ocular mi- 

 crometer in a stereomicroscope at 7, 9, 11, and 14 

 days. Experiments were terminated at 2 wk be- 

 cause after that time it became difficult to ascer- 

 tain the point at which the amputation had been 

 made. The amputation plane can be seen clearly 

 in Figure 1, a control fin 1 wk after amputation. 



Three experiments were performed. Experi- 

 ment I involved exposure offish 3.5-4.2 cm stan- 



» Reference to trade names does not imply endorsement by the 

 National Marine Fisheries Service, NOAA. 



FISHERY BULLETIN: VOL. 78, NO. 1, 1980. 



163 



