Study says whales are adapting to climate change; the same goes for sailors and fishermen

June 14, 2022

Three North Atlantic right whales feed on the surface of the water in Cape Cod Bay. Photo by Brigid McKenna/Center for Coastal Studies, under NOAA research permit #19315-01.

A review of 20 years of tracking data for the highly endangered North Atlantic right whale shows that the population has dramatically changed its feeding and migration patterns as sea temperatures in the Gulf of Maine is getting warmer with climate change.

Findings show that government-imposed protections for right whales – already requiring restrictions on vessel speed limits and lobster and fish fishing lines and buoys – will need to be adjusted as the whales change their movements and their habitats.

After two decades of warming waters in the Gulf of Maine, right whales – a population now estimated at just 336 animals threatened by ship strikes and entanglements in fishing gear – are much more dependent on Cape Cod Bay. because their food supply has changed.

“The time of year when we are most likely to see right and humpback whales in Cape Cod Bay has changed significantly, and right whales are using the habitat much more than 20 years ago,” said Dan Pendleton, a researcher at the New England Aquarium’s Anderson Cabot Center for Ocean Life, in a summary released by the aquarium. Pendleton is the lead author of the study and his team of whale scientists in the United States and Canada.

Published this month in the magazine Biology of global changethe study focuses on how the changing ocean climate affects the phenology of whales – studying recurring biological events, tracking how plants bloom each year or how animals migrate.

The researchers reviewed more than 20 years of data showing trends in the movements of right whales, humpback whales and fin whales. They found that peak use of Cape Cod Bay shifted nearly three weeks later for right whales and humpback whales, correlating with warmer spring weather conditions.

According to the study, right whale activity in the bay increased from February to May, with the greatest increases in April and May. Researchers believe right whales may be using Cape Cod Bay longer because climate change has reduced the amount of their food elsewhere in the Gulf of Maine.

“These changes may have transformed the bay into something of a ‘waiting room’ for right whales as richer prey resources develop in new habitats, such as the Gulf of St. researchers.

In addition to researchers from the New England Aquarium, the study included scientists from the University of Massachusetts at Amherst; the Northeast Climate Adaptation Science Center of the US Geological Survey; the Center for Coastal Studies; University of California at Los Angeles; the National Marine Fisheries Service and the Canadian Whale Institute.

Aerial records of whales from the Center for Coastal Studies on Cape Cod from 1998 to 2018 were analyzed with environmental data, including sea surface temperatures and dates that signify the onset of spring each year.

The team used a new statistical technique to study changes in whale habitat use over years and over years, providing insight into the long-term effects of climate change on whales. whale movements.

The study focused on the Gulf of Maine because it is one of the fastest warming ocean regions, as evidenced by the decline in its northern shrimp fishery and changing groundfish habitat. According to the New England Aquarium, temperature changes at the surface of the sea and at the bottom of the Gulf are three times faster than global averages.

Weather patterns in the Gulf of Maine may have caused right whales to linger longer in Cape Cod Bay, before heading north to the Gulf of St. Lawrence when food is more available there. abundant, the researchers wrote. While in Cape Cod Bay, right whales swim in waters heavily used by shipping, commercial fishing and pleasure craft.

“Vessel speed limits and fishing restrictions in Cape Cod Bay were designed to coincide with the historical peak of North Atlantic right whale habitat use,” according to the New England Aquarium. . “The research illustrates the continued need for government agencies to modify protective measures for threatened and endangered whales as these animals adapt their feeding and migratory habits in response to climate change.”

“Changes in when whales use their traditional habitats have important implications for the design of protected areas. This question is particularly important as climate change continues to alter animal migrations,” Pendleton said.

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