Oyster Spat - Laura Canton

I propose to study the effects of predation and sedimentation on oyster spat and juveniles in subtidal and intertidal habitats of North Inlet, SC. I want to investigate why currently there is an absence of subtidal oyster reefs in SC by examining two potential mechanisms involved in oyster reef success. Previous experiments indicate oysters will settle into subtidal habitats and nonspecific predation increases mortality in newly settled spat. Through a series of manipulative enclosure experiments conducted in the field I will assess predator-specific effects in both intertidal and subtidal locations employing a variety of species known either directly or indirectly to influence oyster mortality (e.g., toadfish Opsanus tau, mud crabs Panopeus herbstii, blue crabs Callinectes sapidus). I also will examine the importance of sedimentation and conduct manipulative field experiments designed to determine if increased subtidal sediment deposition affects the mortality and growth of oyster spat and juveniles. Based on previous studies I expect toadfish will decrease oyster mortality by indirectly reducing decapod predation on reefs and hypothesize that the indirect predation effect actually should be greater in subtidal compared to intertidal habitats. I also expect that increased subtidal sedimentation will increase mortality and decrease growth rates of oyster spat but may have little effect on juvenile oysters. Results should suggest possible approaches for improving water quality and improving existing shellfish management strategies.

My research could convey the importance of ecosystem services provided by oyster reefs. As a member of the filter-feeding bivalves, oysters are able to remove suspended solids and organic matter from the water column lowering turbidity and improving water quality. Oyster productivity and reef structure also attracts a diverse assemblage of organisms including fish, crabs, and mussels. Oysters can therefore have a huge impact on the surrounding community structure. I would like to inspire an appreciation for this organism, which is found all along our coast. I could also stress the importance of recycling oyster shells, because they are the preferable substrate of settling oysters. In the classroom I could bring in aggregates of oyster shells, as well as preserved mud crab specimens to analyze. We could look at live versus dead oysters, mussels incorporated into the shell aggregates, and the various sizes of juveniles attached to the adults. Perhaps we could even do an experiment in an aquarium with live oysters.