Mar 8, 2018 - Energy & Environment

Climate change threatens coastal life as we know it

An endangered right whale breaches on a sunny day off the coast of Georgia

Right whales are endangered again as their feeding grounds are threatened. Photo: Georgia Department of Natural Resources, Permit # 15488

The Gulf of Maine is getting warm — quick. From 2004–2013, sea temperatures there rose faster than almost any other location on Earth.

Why it matters: The Gulf is home to a number of endangered species, and the fisheries there bring in several billion dollars per year to the U.S. and Canada, but the Gulf’s future hangs in the balance. Researchers are scrambling to understand what the warming water means for the people and animals who rely on the ecosystem, particularly as the changes there provide a glimpse into the future of coastlines around the world.

Why it's warming

The Gulf of Maine lies at the intersection of several major ocean currents, including the Atlantic meridional overturning circulation, which moves dense, cold water down and toward the equator. Fresh water from melting sea ice seems to be weakening this current, which could be causing the Gulf to warm faster than other regions.

A combination of cold winters, warm summers, and dramatic tides make the Gulf one of the most productive ecosystems in the ocean. It's a critical habitat for right whales, seabirds like puffins, humpback whales, bluefin tuna and other species.

“If it changes, it will have effects on all of those animals. But it’s also a human place. There are important social and cultural connections people have with this water. If a town loses its identity as a fishing community, it loses part of its history in addition to the economic losses.”
— Andrew Pershing, chief science officer at the Gulf of Maine Research Institute

The impact

Lobster: On the surface, lobster populations appear to be doing well. Sustainable fishing practices and colder temperatures in the northern part of the Gulf have brought in record hauls since 2010. But in Southern New England, the fishery has crashed, with populations declining and the remaining lobsters moving north.

Cod: Climate change and overfishing caused population numbers to fall well beyond sustainable levels. Although there’s active debate over just how many cod remain, everyone agrees numbers are much lower than they used to be.

  • And because of how New England fishing quotas work, low cod populations mean some fishermen are forced to stop fishing for other species that live in the same area, like pollock and halibut.

Herring & Puffins: Climate change has caused herring populations to shift — with consequences for the shorebirds that rely on them. Without herring, puffin parents resort to bringing their babies butterfish. Unlike herring, which are perfectly shaped for young puffin-mouths, butterfish are round. The baby puffins are choking and starving.

Sea turtles: Records of sea turtles in the Gulf of Maine go back hundreds of years, and as their populations have increased, so have sightings. But sea turtle strandings, caused when turtles get caught by the hook of Cape Cod and freeze in cooling winter waters, have been increasing at rates faster than the population is rising.

  • Scientists suspect Gulf warming might be drawing more turtles in, or making them stay longer, putting them at risk once winter comes.
  • Go deeper: We travelled to the National Aquarium in Baltimore, where some of these turtles were being rehabilitated.

Plankton: Calanus, a planktonic animal the size of a grain of rice, is the preferred food of right whales and at the center of the Gulf of Maine food chain. “If you asked an oceanographer to pick one species that would represent the North Atlantic, it would be calanus,” Pershing says.

  • Starting in the 1960s and until 2013, the National Marine Fisheries Service tracked calanus distribution and found a decline. But funding for the research halted, so current distributions are unknown. However, many studies project further declines in calanus abundance as waters warm.

Right whales: Last year, critically endangered right whale populations moved northward, out of the Gulf of Maine and into the Gulf of St. Lawrence, presumably to search for food. But it’s unclear if they found it — this year, for the first time in decades, there were no calves born, which can happen when food is scarce.

Distant visitors: Fish that are not normally found north of Cape Cod have been entering the area, in record numbers. Fishermen report catching sailfish, black seabass, squid, and blue crab, all of which are native to much warmer climates.

The bottom line: When we talk about warming waters, we often talk about shifting populations. Questions revolve around whether or not species will move north fast enough to survive rapidly warming waters. But the recent warming in the Gulf reveals something dramatic: even if animals like right whales follow the cold water north, the habitats they’re entering may not be able to support them.

“You’re not just sliding game pieces north on the map,” Pershing says. “The Gulf of Maine is really special.”
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