Studying the Effect of Green Crabs on Soft Shelled Clam Growth Using eDNA
By Frank Dorsey
On Easter morning at seven o’clock, a remarkable confluence of activities took place just offshore from Sheila Karlson’s former home in Franklin on Taunton Bay. A string of cars and trucks along Route 182 unloaded members of the seven town shellfish alliance to perform clamming conservation. Another string of cars and trucks occupied the driveway. Leading that string were Brian Beal, Gerry Zegers and U. Maine Machias students, followed by researchers from Hancock Soil and Water Conservation District (HCSWCD) and FTB. This collaborative effort was engaged in placing Beal Boxes in Taunton Bay here and at Dwelly Point and in Hog Bay.
The Beal Boxes are used to measure recruitment of clams (Mya arenaria) by allowing free-floating larval clams to settle through a fine mesh on top of the box but preventing mature clams from escaping. The boxes also offer some protection from mature green crabs (Carcinus maenas), though not from those tiny enough to pass through the mesh.
In addition to placing the boxes, baseline core samples were taken at each site. (See the table that follows.)
The first area in which the Beal Boxes were placed is currently a conservation closure from which clamming has been excluded to permit natural re-stocking of clams.
Also present on Easter was another U. Maine Machias professor, Gerry Zegers, who will later sample the areas in the vicinity of the Beal Boxes to establish the relationship between the physical presence of green crabs and the quantity of green crab DNA in the ambient seawater.
In another ongoing study, U. Maine Orono professors Lauren Ross and Sean Smith will use our data findings from the water quality monitoring study (see Water Quality Monitoring in Research) to continue their research on tidal flows in Taunton and Frenchman Bays, and stream flows leading into the bay.
Friends of Taunton Bay is fortunate to have so many collaborative researchers who are interested in the health of Taunton Bay.