PROVIDENCE — An industry-funded study released last month found no significantly negative effect on fish populations during the construction and operation of the Block Island offshore wind farm.
The study crunched seven years of data from monthly trips out to the site in a commercial trawler, which caught ground fish and invertebrates like butterfish, little skate, scup, winter skate and longfin squid.
Scientists compared what they caught near the wind turbines to what they caught in other similar places outside the project area. The only meaningful effect they found by the wind turbines was positive: a lot more black sea bass were congregating around the Block Island wind farm, probably because they like to hang out near physical structures like wind turbine foundations. Scientists also found more Atlantic cod there, but not often enough to draw any firm conclusions.
“It’s encouraging and reassuring, with the caveat that (the Block Island wind farm) is a small project,” said Drew Carey, an author of the study and CEO of the Newport-based firm INSPIRE Environmental. “It doesn’t tell you what 100 turbines are going to be like. (But) it should allay the fears that there would be a catastrophic effect.”
The 30-megawatt Block Island wind farm has five turbines, located about three miles southeast of the island.
As any recreational angler can tell you, fish populations naturally ebb and flow, making this sort of research tricky. But any modest changes to populations caused by offshore wind development, Carey said, are dwarfed by the changes in sea life we’re already seeing from the warming and acidification of the oceans caused by climate change.
“There will be winners and losers among species, but in terms of a net effect, my guess is it’s going to be a positive overall in terms of fish populations,” Carey said.
The study, published March 29 in the ICES Journal of Marine Science, was funded by Deepwater Wind, which was later acquired by Denmark-based Ørsted. Rhode Island coastal regulators mandated that the study take place as part of the approval for the Block Island wind farm. The wind farm started commercial operations in December 2016. The study looked at data from 2012 to 2019, spanning the time before the turbines were spinning to several years into their use.
The Block Island wind farm was a small demonstration project to test the feasibility of offshore wind in the United States. In the coming years, if things go according to plan, it will be joined by hundreds more turbines off the East Coast, several belonging to Ørsted. Those projects sometimes stoke concerns from the commercial fishing industry.
They shouldn’t have to conflict, said David Ortiz, head of government affairs and market strategy in the Northeast for Ørsted.
“This is a really strong data point that should be taken into account as we move forward industry-wide,” Ortiz said in an interview.
According to the study’s authors, it was the first research of its kind in the United States. Every month the FV Virginia Marise would trawl the area to collect ground fish and invertebrates. The study design was developed with environmental regulators and the commercial fishing industry itself, its authors say.
Because they used an actual fishing vessel with commercial gear, it also showed it’s possible to fish between wind turbines themselves. That’s another concern about offshore wind: It could present physical obstacles. The Block Island wind turbines are a half a nautical mile apart; other projects coming down the pike will be a full nautical mile apart. The study showed that it was possible to trawl between turbines without snagging on a cable, said INSPIRE’s Carey.
The results were largely in line with previous studies in Europe, which is ahead of the U.S. in offshore wind power development, the authors say.
The study not only looked at what fish were caught, but also what sort of condition they were in and what was in their stomachs. Some were eating more mussels, which indicated they were feeding off of mussels growing on the turbines themselves.
“That was pretty neat,” said Dara Wilber, the lead author of the study who also works at INSPIRE Environmental. “It’s an indirect way of seeing what the fish are feeding on.”
Otherwise, though, they found no physiological differences in the fish — in stomach fullness, for example — that could be attributed to the wind farm, the authors say.
Wilber noted that the research was on a wind farm at pilot scale. Monitoring for fish populations will continue as the industry goes from pilot scale to commercial scale.
“In some ways, it’s lessons learned by the industry in how to build and put out the turbines, but also by us biologists about how to monitor” for impacts on marine life, Wilber said.