With Cape Wind hoping to break ground in the coming years and a huge new swath of ocean opened for wind farm development south of the Vineyard, the impact of turbine noise on fisheries is still poorly understood.
“The long-term impacts of these wind farms are just totally unknown,” said Woods Hole Oceanographic Institution biologist Scott Gallagher this week.
The lack of data puts state and federal regulators in the unusual position of holding the purse strings for research that could reflect negatively on the offshore wind projects they are aggressively pursuing.
Some studies have begun to provide possible hints about how marine life might be affected by underwater turbine noise. Whales, for example – perhaps the most charismatic animals that frequent local waters—offer a rare glimpse of scientific understanding in the industry.
Peter Tyack, a leading whale biologist at the University of St. Andrews in Scotland, says that the past decade of European observation should assuage fears of habitat loss.
“The bottom line is that operating wind farms really do not have much of an effect on whales,” he said. “I don’t think once a wind turbine is in place it’s likely to have an impact more than 100 metres away.”
At their closest, Cape Wind’s 130 turbines will be spaced 630 metres apart.
Mr. Tyack said that wind farms could pose a problem if placed in primary feeding grounds like Stellwagen Bank northeast of Boston, but were unlikely to have much of an effect in an area that sees only occasional migration like Nantucket Sound – that is, except during construction.
“Coastal harbor porpoises and baleen whales can be sensitive to pile driving at a ranges of miles away, which is why they should time construction for those months when the whales are unlikely to be there,” he said.
The potential impact on fisheries, however, remains an open question. Biologist T. Aran Mooney of the Woods Hole Oceanographic Institution specializes in the alien world of underwater sound. Fish use sound, mostly low frequency, in displays of courtship and aggression, as well as to passively listen for predators and prey. They also use sound to orient themselves in the water by, for instance, listening for the proximity of waves on the ocean surface.
It wasn’t until a little over a year ago that research from Mr. Mooney’s lab confirmed that squid (such as the local loligo pealeii or longfin inshore squid which migrates to the Vineyard every May) could even detect sound. In his office on Tuesday, Mr. Mooney showed off his most recent research. On his computer, a video showed a squid in a tank exposed to low frequency sounds. Low frequency sound can simulate not only fish noise but also human activity such as shipping and pile driving. In the video, when the noise started, the squid darted frantically around the tank.
Mr. Mooney said that after a number of trials the squid’s response to the noise became less dramatic, but it never lost its skittishness.
“It doesn’t totally go away. It’s kind of a reflex where they’ll just sort of flinch a little bit or change color,” he said. “It seems to me like maybe that means that it’s somewhat vital to their survival. You don’t want to ever lose that sense of potentially detecting a predator.”
What effect noise from wind farms will have on that reflex Mr. Mooney doesn’t know.
He characterized the underwater noise output of wind farms and of boat traffic as continuous low frequency noise. (Turbine noise underwater comes primarily from the gearboxes and generators at the top of the towers).
“It’s sort of like living near Route 28,” he said. “You could get used to it after awhile and you probably don’t notice it most of the time. But it could increase your stress levels without you knowing it.”
Most fish share the squid’s primitive hearing system. When asked what effect the turbines will have on the area’s fisheries he was blunt.
“We really have no idea,” he said.
Surprisingly, most European wind farms that have been operating for years offer little in the way of guidance, because they did not conduct baseline fish surveys before they were constructed.
But Mr. Mooney says that it may be just as likely that the turbines could be a boon to local fishermen, as the Environmental Impact Statement for Cape Wind boasts. In Denmark mussel and crab communities have been observed to flourish around the towers.
“It could create structure, and attract fish,” he said. “If you’re in the middle of a sand flat and there isn’t that much there, then maybe it’s a really good place to put these things. We don’t know. That’s the whole goal, to go and look.”
Mr. Mooney and colleagues have secured funding from NOAA’s Sea Grant program to deploy acoustic equipment in Nantucket Sound to establish a baseline of sounds produced by animals over the next two years, before construction begins, and he says that Cape Wind has been cooperative throughout the process. But to measure the effect of the turbines Mr. Mooney is hoping to secure funding through construction and beyond.
Downstairs, at the Woods Hole Marine Research Facility, biologist Scott Gallagher is hoping to get a glimpse of what effect the wind farm will have on the sea floor community (once again Europe provides little in the way of example: the Baltic Sea, home to many wind farms, is anoxic at depth and supports little in the way of benthic life). He hopes to take millions of pictures of the Nantucket Sound sea floor before, during and after the construction of the turbines. Unable, on his own, to analyze the trove of data that will result Mr. Gallagher hopes to recruit the public to help identify the fauna present at each stage. It’s an approach he acknowledges may not be popular with developers.
“If the pictures are available on a public Web site, then the impact of the wind farm is totally transparent – everyone can log on and see what’s going on, so getting this funded might be one of the hurdles,” he said laughing. With the government making a push for offshore renewable energy, funding studies that could ultimately show detrimental effects may not be a high priority. As a result, Mr. Gallagher said that he is also seeking private funding for the project.
On Tuesday Mr. Gallagher brought up pictures of a colorful sea floor community in the Sound, where starfish, scallops and dogfish vied for camera time. Some short-term effects of turbine construction are certain, such as the burial of clams, scallops and snails, as high powered jets clear the path for the lattice of transmission lines a few meters underground that will connect the structures to a central hub and then to the mainland. Longer-term effects are less certain.
“So little is known about electromagnetic fields in seawater,” he said. “Certainly sharks like dogfish detect electromagnetic fields very well. This whole region might be inundated with dogfish within several months or they might be totally repelled by it. We don’t know. It’s that kind of unknown characteristic of predator prey interactions that are just unpredictable at this point but that could have a huge impact.”
Mr. Gallagher said that he has also met resistance from potential funders who assume that the waters near Woods Hole must be teeming with data. In fact, Mr. Gallagher says, he has had to rely on just one benthic survey of Nantucket Sound from 2001. All others, he says, date to the 1930s and 40s.
“There’s just very little data out there,” he said. “That’s why we want to do this.”
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