DEI has been conducting research in the Freeport area since 2013 to understand the causes of a declining soft-shell clam population in the northern region of Casco Bay. Work by DEI staff – Kyle Pepperman, Bennett Ellis, Cody Jourdet, Justin Lewis, Amelia Slocum, George Protopopescu, and Sara Randall, and UMM faculty – Brian Beal – has focused on a variety of factors including ocean acidification, predation, and recruitment limitation as well as ways to combat the decline. On Monday, May 22nd, Penelope Overton, staff writer at the Portland Press Herald, wrote a front-page article about one of the half-dozen field experiments that are currently underway on Freeport’s flats. The study is examining the time of year clams settle from the plankton to the flats, and what the intensity of settlement is at several sites located on the eastern side of the Harraseeket River. The work is a continuation of efforts initiated in 2015 using 1-ft x 2-ft x 3-inches tall wooden “recruitment boxes” designed to capture clams that settle out of the plankton and fall into the boxes (that are covered on top an bottom with an industrial strength window screening). The initially empty boxes are deployed typically in the spring, and are left in place on the surface of the mudflat until November when they are removed and the contents of each box examined carefully. Boxes in the Harraseeket River tend to fill with mud (some boxes weigh as much as 25 pounds by November), and may contain as many as fifteen different species of marine invertebrates, including soft-shell clams. Some boxes have had as many as 6,000 clams (3,000 per square foot) by the November sampling event, with sizes ranging from 1/8th of an inch to 1-1/2 inches. Samples of the mudflat adjacent to the boxes (i.e., controls taken from unprotected portions of the same flat) typically contain zero to as many as 2 clams per square foot. In the study reported in the Press Herald, boxes are being deployed at five locations on the east side of the Harraseeket River every two weeks from the beginning of May through mid-September. All boxes will be removed and sampled in mid-November. The work is supported by funding from the University of Maine at Machias, Maine Economic Improvement Fund – Small Campus Initiative, and Sea Pact.
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