Predator-prey relationships in mummichogs (Fundulus heteroclitus (L)): Effects of living in a polluted environment

Analysis of prey capture ability of mummichogs, Fundulus heteroclitus (L.) from a mercury-polluted tidal creek compared with conspecifics from an uncontaminated environment showed that the latter captured the prey organism Palaemonetes pugio Holthuis at a significantly faster rate and had significantly lower levels of mercury in their brain tissues. Exposure of uncontaminated fish to conditions similar to those of the polluted creek caused both a reduction in their prey capture rate and an increase in brain mercury to levels similar to those of fish native to the creek. Polluted fish maintained in the laboratory for extended periods failed to show either an increase in prey capture rate or a decrease in their levels of brain mercury. Size-selective predation on grass shrimp was observed among mummichogs from both sites, but did not appear to vary between sites. Videotape analysis of predatory behavior showed that fish from the polluted creek made significantly fewer attempts to capture prey. Fish from the polluted environment suffered significantly greater mortality in the presence of a predator, the blue crab Callinectes sapidus Rathbun, than fish from the unpolluted environment. Copyright (C) 1997 Elsevier Science B.V.