August 17, 2023 — The reports have come from up and down the coast of Maine: Blue crabs have been spotted around dock pilings, pulled up in lobster traps and found washed up on beaches.
The crabs, usually associated with coastal Maryland and the Chesapeake Bay, have been showing up more often and in larger numbers in the Gulf of Maine over the past few years. To better understand the shifting population, scientists are now asking fishermen and members of the public to report their sightings through an online survey.
Jessie Batchelder, a fisheries project manager with Manomet, a Massachusetts-based nonprofit focused on conservation and science education that has been studying blue crabs in Maine, said the information submitted by lobstermen, clam harvesters and others who are frequently on the water is key to getting a better picture of the blue crab population.
“They have a vast knowledge of what’s going on and what they’re seeing,” she said.
In the past, researchers would occasionally hear about stray blue crabs being found in lobster traps or by clam harvesters, but the reports started to become more frequent in 2021. That got researchers thinking about studying how blue crabs are moving into the Gulf of Maine as waters warm because of climate change, Batchelder said.
Last year was the second warmest on record in the Gulf of Maine, with an average surface water temperature of 53.66 degrees Fahrenheit. While that temperature fell just short of the 2021 record, it continued the Gulf’s historic trend as one of the fastest-warming ocean areas on the planet.
The Gulf of Maine, 36,000 sprawling square miles stretching from Cape Cod to Nova Scotia, is home to rare whales and seabirds, valuable fish such as cod and haddock, and the $1.5 billion U.S. lobster industry, all of which are affected by warming waters.