Last year was the warmest on record in the Gulf of Maine, with average sea surface temperatures that shattered the previous record set during a massive 2012 “ocean heat wave” that triggered invasions of green crabs, puffin chick starvation and an early lobster shed. .
Surface temperatures in 2021 exceeded normal by 4.2 degrees Fahrenheit, the highest deviation in 40 years that satellite records of sea surface temperatures have been collected in the Gulf, according to a new report released Monday. by scientists at the Gulf of Maine Research Institute in Portland. For comparison, the year 2012, the “great ocean heat wave”, had an anomaly of 3.7 degrees.
“It’s quite significant from a climatological standpoint, but it’s likely to be one of the coldest years we’ll experience in the indefinite future,” said co-author David Reidmiller, director of the Climate Research Center of the GMRI. “We are almost certain not to reach zero (greenhouse gas) emissions overnight or next year or in the next decade, so we will see this warming trend continue.”
For the past 18 years, the Gulf of Maine has been one of the fastest warming parts of the world’s ocean, threatening a body of water that is home to many cold-water species already living in it. the southern limit of their range. The changing climate regime – driven by changes in the jet stream and the course and speed of the Gulf Stream and Labrador Current aided by the rapid melting of the Arctic and Greenland ice sheets – has been implicated in changes in the abundance of lobster, endangered right of the North Atlantic the feeding grounds of whales and the food on which puffin chicks, herring and other species depend.
“Even though breaking temperature records is becoming almost the norm now, there will be more surprises in store and staying tuned to what’s happening in the gulf is very important,” said Nick Record, biological oceanographer at Bigelow. Laboratory for Ocean Sciences. at Boothbay, which did not participate in the report. “A lot of what we see changing in the Gulf of Maine is directly related to temperature, so that’s probably the most important variable to track.”
Puffins are considered one of the canaries of the coal mine for warming effects, and they’ve had a tough year in 2021, likely because warm temperatures are reducing populations of tiny fish the birds feed their chicks. In the Gulf’s largest puffin colony on Machias Seal Island – a disputed border territory occupied by Canada – scientists have recorded the worst survival results ever. On average, 75% of hatchlings survive and fledge at the end of each season, but last year that figure was just 6%.
“Growth rates were very slow and it looked like the adults were unable to find food to feed their chicks,” said Heather Major, associate professor of biology at the University of New Brunswick, who is leading the efforts to surveillance on the island. “Even the puffins that survived to 35 days – when they are considered old enough to successfully fledgling – were very small and mostly covered in down. We expect these youngsters to not have survived once they left the island.
Sea surface temperatures around the island, Major said, were warmer than normal throughout the bird breeding season.
The situation was not much better in the other islands of Maine. At Petit Manan, off Jonesport, only 10% of puffin pairs successfully raised a chick, and at Matinicus Rock that figure was 34%.
“We’ve seen puffins and terns feeding their chicks fish more suited to warm water, like butterflyfish and rough scad,” which don’t have as much nutritional value, recalled Don Lyons, manager. of the National Audubon Society’s Seabird Institute, which watches over colonies on several mid-coast islands. “The puffins at Eastern Egg Rock even appeared to be scavenging cut fish – possibly bait thrown by anglers – which was a new sighting.” Unusually heavy rainstorms—another predicted effect of global warming in Maine—flooded the nests, causing many wet chicks to die.
“Even the chicks that survived to leave the islands were often very skinny and small for their age,” he noted. “Our technicians on the island have started calling some of the young puffins ‘micropuffins’.
GMRI’s Kathy Mills, co-author of the warming report, said they continue to see warmer water species like longfin squid and black bass entering the Gulf of Maine, but that’s not shocking. more people. “These changes could have been really eye-catching in 2012 and they’re still happening now, but maybe we’re getting more familiar with them,” Mills said.
That said, some of the most destructive developments seen following the 2012 heatwave did not occur in 2021, including an explosion of destructive green crabs that devour mussels and destroy eelgrass meadows and lobsters that come off early. , which can throw one into the seasonal expectations of lobster processors and markets. The first lobster shed in 2012 led to violent confrontations between Canadian fishermen and truck drivers bringing lobsters from Maine to saturated New Brunswick processing plants.
Scientists said the main reason these immediate effects were not seen this time around would be that the worst warming anomalies in 2012 occurred in the spring, which sets the tone for many species, when ‘they happened in late summer and fall last year. .
The GMRI reported that the average sea surface temperature in the Gulf in 2021 was 54.1 degrees, half a degree higher than in 2012 and 4.2 degrees higher than the average for the period. “normal” between 1982 and 2011, before ocean heat waves became commonplace.
The five hottest years for the Gulf have all occurred since then, with 2016, 2020 and 2018 taking third, fourth and fifth place.
The longer-term warming trend has been linked to other ecological changes, including more frequent sightings of warmer-water species such as ocean sunfish.
October 2021 was particularly notable in that each day set an all-time daily record for average sea surface temperatures in the Gulf. For the whole year, scientists found daily records on 46% of the days – 169 daily records in all.
“The good news is that the future is still in our hands,” said GMRI’s Reidmiller. “If we are able to reduce greenhouse gas emissions globally, we can certainly limit the changes we see in the future.”