Metal Impacts on Benthic Macroinvertebrate Community and Their Implications for the Feeding Habit of Mummichogs

Daisuke Goto (1) and William G. Wallace (2)

(1) Program in Biology, Graduate School and University Center, CUNY, 365 Fifth Avenue,
New York, NY 10016. dgoto@gc.cuny.edu

(2) Biology Department, College of Staten Island, CUNY, 6S-310, 2800 Victory Boulevard
Staten Island, NY 10314. (718) 982-3876, (718) 982-3923. wallace@mail.csi.cuny.edu

Anthropogenic stressors such as metals can often alter the structures and functions of benthic food webs at tidal salt marshes. As benthic macroinvertebrates are in direct contact with metals in sediments, benthic community composition often indicates metal contamination levels in the environment. Benthic macroinvertebrates are also common prey items often found in the guts of various fish feeding at marshes. To test the hypothesis that metal impacts on benthic macroinvertebrate prey affect the feeding habit of mummichogs (Fundulus heteroclitus), one of the most abundant resident fish at tidal salt marshes near a highly industrialized area, the Arthur Kill (AK), NY/NJ, benthic macroinvertebrates and mummichogs were collected from AK as well as a local reference site near Raritan Bay in mid-summer of 2004. The benthic community composition at the polluted sites showed that there were significantly higher abundances of pollutiontolerant polychaetes including Hobsonia florida and Nereis acuminata, as well as oligochaetes, and fewer pollution-sensitive species (e.g., amphipods and gastropods) than those at the reference site. The gut contents of mummichogs from the polluted salt marshes indicate that altered benthic prey community composition was reflected in the diet composition of mummichogs. A significantly larger amount of gastropods was observed in fish from the reference site than the polluted sites, while a significantly larger amount of polychaetes was observed in fish from the polluted sites than the reference site. Additionally, both the benthic community composition and gut contents of mummichogs at the polluted sites showed significantly lower species diversity than those at the reference site. These results show that metal accumulation in sediments at AK seems to have strong implications for altered species interactions in benthic food webs at AK.