Warming Oceans Rapidly Destroying New England Fisheries: Gulf Of Maine Lobster Faltering
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Fast-warming seas cause all sorts of problems for fish at each stage of their development. For centuries, the Gulf of Maine has operated like a sub-Arctic ecosystem, with very cool temperatures for part of the year and then routine, seasonal warm-ups. Every creature along the food chain had adapted to that pattern. Calanus, a tiny, crustaceous zooplankton which resembles a micro-shrimp, about the size of a grain of rice, feeds voraciously on cool-water phytoplankton (marine algae) in early spring. The tiny shrimp get good and chubby and then go into hiding deep-down for a few months, re-emerging in the autumn full-grown, and looking mighty good to a herring, which in turn, looks mighty good to a cod. That life-sustaining chain is disrupted by heat spikes in the spring, which throws off Calanus development. “When things warm up, what we suspect is that its metabolism is clicking along so fast that it can’t build up the reserve of fat it needs, so it isn’t able to complete its life cycle the way it normally would,” Pershing told me. When the little creatures can’t adapt, the predator fish take the hit too. The ones who survive have often expanded their search for sustenance into waters further north.
Lobsters have made this migration too, which is why fisherman working the Long Island Sound said their goodbyes to that cash crop a long time ago. In the Gulf of Maine, fishermen saw their lobster “landings” (the industry term for the number of caught fish) begin to triple during the late aughts. The frame of optimal conditions moved from Southern New England to Maine, giving the state an unprecedented boom, a high point of 132 million pounds of lobster landings in 2016 as opposed to 57 million pounds of lobster in 2000. The Southern New England lobster industry is on life support, and Maine’s boom is not likely to last.
According to a study published recently in the journal Ecological Applications, warming seas are altering biological dynamics in the waters off Maine, and peak conditions for lobsters are now moving north again. “We predict that in many of the areas in the Gulf of Maine, landings will return to levels around the mid-2000s within the next four to six years,” Noah Oppenheim, Executive Director of the Institute for Fisheries Resources and one of the study’s authors, told me. A fisherman-turned-marine-biologist, Oppenheim looked not only at food chain issues, but at how juvenile lobsters respond to hot spots in the ocean while they instinctively choose a safe space to mature. “They’ll bounce off 12 degree [Celsius] water like it’s a wall,” Oppenheim said. “Lobsters avoid water that’s too warm. They have a break point where their pulse will decrease and their organs begin to fail.”
Oppenheim is hoping that his predictions will help humans respond to these new ecosystem conditions. “It’s going to be a rough few decades, IPCC made that crystal clear,” he said, referencing the September 25 ocean report from the International Panel on Climate Change, which predicts that the maximum catch potential rate of global fisheries will decrease at a rate of 4.1 percent per decade, a direct result of global warming. “We need to decarbonize the economy so that we can prevent worse outcomes, the ones we’d rather not have to predict,” Oppenheim added.
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https://newrepublic.com/article/155586/global-warming-already-destroying-new-englands-fisheries
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