Lauren Salisbury

Project Title: EFFECTS OF OYSTER AQUACULTURE ON BENTHIC MACROINVERTEBRATES IN COASTAL PONDS OF SOUTHERN RHODE ISLAND

Mentors: Chelsea E. Duball, Jose A. Amador, & Mark H. Stolt

Abstract: Oyster (Crassostrea virginica) aquaculture in the coastal ponds of southern New England has become increasingly popular over the past twenty years.  Although oysters are native to this area, little is known about the effects of oyster aquaculture on the infaunal benthic community under aquaculture. The anthropogenic effects of continuous oyster aquaculture could change the trophic structure of these ecosystems. We studied three coastal ponds in southern Rhode Island used to grow oysters commercially.  Aquaculture sampling locations were selected by age to survey the change in functional feeding group counts over time, and one control site was established in each pond. Organisms were collected from the first 20 cm of substrate using five benthic cores per site. The soil was sieved, the organisms preserved in ethanol, and stained with rose bengal. Organisms were identified to the species level using a microscope and dichotomous keys, then sorted into functional feeding groups. We found organisms belonging to seven feeding groups: deposit feeders, suspension/filter feeders, interface feeders, scavengers/collectors, grazers/scrapers, predators, and parasites.  Our data show that aquaculture sites have more deposit and interface feeders than control sites, possibly due to biodeposit accumulation under aquaculture racks, which may attract deposit feeders and alter the trophic structure of the infaunal community. In one pond, we found that the newest aquaculture site (established in 2010) had the highest number of organisms.  Our results indicate that continuous aquaculture may lead to changes in the size and structure of infaunal communities.