EFFECTS OF MERCURY ON THE FEEDING-BEHAVIOR OF THE MUMMICHOG, FUNDULUS-HETEROCLITUS FROM A POLLUTED HABITAT

Fish living in contaminated environments may exhibit reduced growth which may be due, in part, to the impact of toxicants on prey capture ability. We studied the effects of methylmercury (meHg) and mercuric chloride (Hg) on feeding of Fundulus heteroclitus from Piles Creek, a polluted habitat in Linden, New Jersey. We found that exposure to 0.01 mg/liter of meHg for one week had less impact on the prey capture rate than exposure to a similar concentration of Hg. Exposure to 0.01 mg/liter for two weeks or to 0.02 mg/liter for one week, of either meHg or Hg, produced significant reductions in feeding rate, compared to controls. In general, the fish were affected to a greater degree by exposure to Hg than to meHg. This is the reverse of the usual order of toxicity, but is in keeping with previous observations on this population, in which we have noted that gametes and embryos had developed tolerance to meHg, but were more susceptible to Hg.