Undergraduate Research and Creativity

URECA

2008-2009

Can Codium fragile provide juvenile bay scallops
an above-bottom refuge from benthic predation?

Kate A Lavelle, John M Carroll, Bradley J Peterson
School of Marine and Atmospheric Sciences

Eelgrass (Zostera marina) is recognized as being the preferred habitat of bay scallops (Argopecten irradians), providing an above-ground spatial refuge for juveniles until they reach a size predation threshold. However, eutrophication, harmful algal blooms, and habitat loss have significantly reduced eelgrass abundance along the historic range of bay scallops. In Long Island estuaries, populations of bay scallops have declined dramatically in correlation with the loss of eelgrass meadows. An introduced and locally abundant macroalgae (Codium fragile) may serve the same role as a predation refuge since juvenile scallops have been observed attached to the C. fragile canopy in the field. The purpose of this study was to quantify the role of C. fragile as an above-bottom refuge for juvenile bay scallops from crab predation. In a laboratory experiment, juvenile scallops (mean shell height 12.6 mm) were tethered to both eelgrass and C. fragile canopies. Mud crabs (Dyspanopeus sayi) were allowed to forage for the scallops for 24 hours. Scallop survival in eelgrass and C. fragile showed no significant difference. Survival statistics indicate that C. fragile may provide a comparable predation refuge from benthic crabs for juvenile scallops as Z. marina. This project was supported by URECA and the Evan Frankel Foundation.