An Evaluation of Boat Basin Dredging Effects: Response of Fishes and Crabs in a New Jersey Estuary

Abstract

Dredging is one of the most common human modifications of estuaries and although its effects have often been studied, there has been little effort in evaluating the effects on mobile macrofauna, such as fishes and crabs. We evaluated the response of fishes and crabs to 4 d of dredging in a small boat basin within a polyhaline marsh creek of a New Jersey estuary. We used several measures, including fish and crab species composition, abundance, and size from trap collections and movements of marked mummichogs Fundulus heteroclitus before, during, and after dredging. In general, the fauna changed little during the 4 d of dredging relative to the 1.5-month sampling period. Species composition variations that did occur may have been due to seasonal changes that are typically observed during the fall based on annual sampling at this site. The movement of tagged mummichogs was minimal, with most recaptures taking place in the boat basin. Individuals that left the boat basin moved into pools in an adjacent marsh for the winter. These results suggest that the short-term effect of this low-sediment-volume dredging project was negligible for the benthic fishes and crabs studied, which we believe are representative of the high-salinity portions of estuaries in the northeastern United States.