Hunt, H. L. Woods Hole Oceanographic Institution, hlhunt@whoi.edu
Mullineaux, L. S. Woods Hole Oceanographic Institution, lmullineaux@whoi.edu

 
SPATIAL VARIATION IN RECRUITMENT OF SOFT-SHELL CLAMS: THE ROLES OF POSTLARVAL TRANSPORT AND PREDATION
 
Both postlarval transport and predation are known to influence the distribution and abundance of recruits of the soft shell clam Mya arenaria and other bivalves. We hypothesize that there is a critical size below which juvenile M. arenaria are susceptible to transport in tidal flows and that spatial variation in abundance of clams below this size is hydrodynamically controlled while that of larger individuals is determined by mortality, particularly predation. We are testing this hypothesis by monitoring spatial variation in abundance of small postlarval clams in Barnstable Harbor, Massachussetts, and by examining the susceptibility of postlarvae to resuspension and predation. Spatial variation in abundance of settlers and small postlarvae was monitored weekly at two spatial scales (metres and 100s of metres) from June to October 1998. We examined size-dependent rates of erosion of postlarvae under a range of flow conditions in a laboratory flume. In the laboratory, we also examined the vulnerability of small postlarval clams to a suite of potential predators. Hermit crabs, and small juvenile green crabs and horseshoe crabs consumed the largest numbers of clams. Field experiments manipulating predator abundance and field monitoring of rates of tidal transport are planned for next summer.
 
Day: Thursday, Feb. 4
Time:
Location: Sweeney Center
 
Code: SS24TH0415H