Edgartown and Oak Bluffs selectmen met together Monday to address the growing problem of bacterial pollution in Sengekontacket Pond. The boards agreed to work jointly to improve water quality.
In July, Massachusetts Division of Marine Fisheries biologists told Edgartown and Oak Bluffs shellfish constables that Sengekontacket Pond would need to be closed to shellfishing as a result of sustained high levels of fecal coliform bacteria. The state has reclassified the saltwater pond that is connected to Nantucket Sound by two channels spanned by bridges as a "conditionally approved area." Under that classification, which does not affect swimming or boating, shellfishing is only allowed from October 1 to May 31 until further notice.
The two boards of selectmen agreed to appoint a joint committee of town officials, activists, and local experts from Oak Bluffs and Edgartown to formulate a plan to improve water quality and reduce the amount of time the pond is closed. "We don't assume that we'll solve the problem here this afternoon, but maybe we can start working together on it," said Oak Bluffs selectman Duncan Ross.
The committee, which will be officially formed when selectmen in the respective towns appoint the members, will include a shellfish officer, a selectman, and a conservation commission member from each town. The towns will also invite Bill Wilcox, Martha's Vineyard Commission water resource planner, Gus Ben David, former director of the Felix Neck Wildlife Sanctuary, and a representative of the Friends of Sengekontacket Pond to join the committee.
Birds to blame?
There is growing sentiment among local shellfish constables that cormorants nesting on Sarson's Island in the middle of the Sengekontacket Pond are a significant source of pollution. Sarson's Island also straddles the border between the two towns. They also believe that dog feces near boat ramps and access points is making its way into the pond, and that large flocks of resident Canada geese are also a source of contamination.
Bird experts agree the population of double-crested cormorants, uncommon on the Island just 20 years ago, has exploded in recent years, to the detriment of other species of fish and birds. Because cormorants are a migratory bird, they fall under the regulatory responsibility of the federal government and are protected under the Migratory Bird Treaty Act.
"It's not as simple as controlling the deer population," said Mr. Ben David. "What part of the pie we can blame on the cormorants, I don't think we have enough information. Exactly how much has to be ascertained with good science. There isn't any doubt they're definitely part of the problem."
Joe Alosso, facilities manager for the Oak Bluffs and Edgartown wastewater plants, noted that recent development along the shoreline puts pressure on the pond's ecology. "There's been a ton of construction. There's a lot more homes," he said. "I would maintain that if you got rid of all the cormorants, you would still have water quality issues. I think it's more than birds."
Edgartown shellfish constable Paul Bagnall agreed that more study is needed to determine the exact sources of pollution, but he urged the boards not to delay other actions. "While we're proving what percentage causes what pollution," he said, "we can work on other aspects, dredging, doing what we can to deal with birds, urging people to curb their dogs around boat ramps, fixing up what few spots that we have rainfall [runoff] directly into the pond."
Ponds under a microscope
A recent study (available here) lends strong support to the view that birds are a significant source of pollution in the Island's saltwater ponds.
In September, the University of Nehe w Hampshire's (UNH) Jackson In Estuarine Laboratory studied water samples from four salt ponds on the eastern side of Martha's Vineyard. Included in the survey were Sengekontacket Pond, Farm Pond, Eel Pond and Trapps' Pond.
Scientists from UNH used a relatively new technique called microbial source tracking, to determine the source of fecal contamination. Water samples from the four ponds were analyzed using a DNA process similar to the technique used to identify human criminal suspects. By matching the microscopic strands of genetic material to known samples taken from various species in the region, the scientists were able to identify what species the bacterial pollution came from.
The water samples were collected on September 7, at a time the pond was closed to shellfishing. The samples were processed at the Wampanoag Environmental Laboratory in Aquinnah, then transported to the UNH lab.
The report concludes that cormorants, Canada geese, and other birds are significant sources of contamination in all of the ponds. It says Canada geese are by far the dominant contamination source at Farm Pond. There is also scientific evidence that cormorants and dogs contribute to bacterial pollution in Sengekontacket Pond. The study also found a relatively large number of samples that could not be identified by species.
The study found no human-borne bacterial pollution, though it is possible a wider range of sample locations in future studies might reveal some amount of contamination by humans.
Dave Grunden, Oak Bluffs shellfish constable, says it is important to understand that the study measured only bacterial contamination. It did not address nutrient loading from residential septic systems, which he and others believe is a significant source of ecological damage.
"It's a one shot deal, a spot check, to help point us in a direction," Mr. Grunden said. "It's not going to give us the whole picture. Sampling at a couple of places along State Beach doesn't give us an idea what's going on up in Majors Cove, over by the golf course. We will be developing a procedure, and picking additional sites to continue this."
Friends of Sengekontacket Pond, a non-profit group formed to protect the watershed, funded the study at a cost of approximately $9,000.
Mr. Grunden said he and Mr. Bagnall are discussing the best way to continue this kind of water quality monitoring. He says further study, including a broader range of sample locations over a longer period of time, will be expensive.
"The forming of this committee is going to be a great step forward," Mr. Grunden said. "Although it's two towns, it's one watershed. This will give us the opportunity to work towards one management plan for the entire pond, to the benefit of both towns."