"The synergistic effects of multiple projects may be more than additive and this may not be sufficiently identified in project-specific documents; therefore, losses may be undercompensated by taking a project-by-project approach," they continued.

In addition, the Pacific Fishery Management Council, which represents the region encompassing the entire West Coast, penned its own letter to Lefton, similarly warning about the impacts of offshore wind development on fisheries.

The council said every proposed offshore wind lease area with multiple projects could negatively impact the ecology of the marine ecosystem, the fisheries the council manages and local fishing-dependent communities.

The letters from the regional councils — which Congress established in 1976 to manage the nation’s marine fishery resources — came after BOEM proposed guidance in June to ensure offshore renewable energy development "occurs in a thoughtful manner" and that its conflicts with fisheries are minimized. Lefton said at the time the agency was seeking "open and honest conversations focused on finding solutions."

"We recognize the need for renewable energy and the role these energy sources will play as we work to reduce our reliance on fossil fuels. However, addressing climate change should not require significant negative impacts to food producers or to our ocean environment," Seafood Harvesters of America, a national organization representing thousands of fishermen nationwide, wrote in a letter to Lefton.

"We remain deeply concerned that these guidelines are simply recommendations and hold no promise of any actual mitigation or compensation for the fishing industry," they continued. "Any potential effectiveness of these guidelines is negated by the fact that they are only suggestions for offshore wind energy developers, rather than binding requirements."

In a separate letter, U.S. Small Business Administration Office of Advocacy Chief Counsel Major Clark said his department had heard concerns from heard from "small commercial fishermen, port operators, marine equipment retailers, onshore processors, fish markets, and other fishing industry representatives."

"Small businesses renewed their concerns regarding their inability to adequately comment on mitigation measures without knowing the impacts that offshore wind development activities will have," Clark wrote. "There are simply too many unknowns for the current guidance to be effective."

Since the beginning of the year, more than 20 humpback whales and endangered North Atlantic right whales have been discovered dead along the East Coast with most beaching in New Jersey, New York and Virginia, according to federal data. The uptick in deaths has led to calls from lawmakers, local officials and conservation organizations for a federal moratorium on wind development in the Atlantic Ocean.

While administration officials and some environmental groups have said there is no evidence suggesting wind turbine construction is killing whales and that the deaths are part of an "unusual mortality event" for both whale species dating back years, the region is on pace to far surpass death figures set since the mortality events were declared.