Associate Professor Thomas Trott presented research on changes in the ecosystem of Cobscook Bay, Maine, at the 2007 meeting of the New England Estuarine Research Society (NEERS).
The intense commercial harvesting of species that require dredging, such as scallops and sea urchins, is the probable cause of the faunal shift detected through field sampling, according to Trott, of the Biology Department.
Dredging disturbs sediments
The dredging directly impacts species falling under the heavy dredge path, according to Trott. A more insidious effect is the disturbance to sediments that become suspended in the water column and redistributed throughout the bay by strong water currents.
“When these sediments settle out, they change the bottom characteristics,” he said. “The animals that I study have specific requirements for hard, rocky bottoms. The areas that I sampled now have muddy bottoms, and so the animals that are now found there are characteristic of that type of substrate.”
Mussel beds now predominate in the bay as a result of this faunal shift, and there is a real concern that they may overtake areas where scallops normally are found.
“Because scallops are of high commercial value, there could be a serious impact on the economy of local fishermen. Another impact is the change in community structure of the bay. Because communities are connected through food webs, change could bring about unforeseen changes in the abundance and distribution of many species, some that I did not sample,” said Trott, who conducted his research at Suffolk's R.S. Friedman Field Station on Cobscook Bay through grants from the Maine Chapter of the Nature Conservancy.
The July issue of Downeast Magazine will include an article on Trott’s work in Cobscook Bay and his collaboration with colleagues on the Canadian Biodiversity Discovery Corridor.
The Friedman Field Station is located on one of the very few macrotidal estuaries in the United States and is an embayment that has the highest biodiversity north of the tropics.
The 2007 NEERS meeting was co-hosted by the Bigelow Laboratory for Ocean Sciences and the Maine Department of Marine Resources. NEERS is a 500-member organization of coastal research scientists and students from New England and Atlantic Canada.
Outer Birch Island, one of five study areas in the Cobscook Bay region.