August 26, 2012 — The ocean waters in New England have been heating up in recent years and fishermen and scientists are looking closely at the changes that warmer water may bring to our marine environment and its inhabitants.
Fish are very sensitive to any changes in temperature and with many of the commercial species in New England already at the southern limit of their range, there are fears that such warming may force some fish to abandon historically abundant areas such as Georges Bank for cooler waters.
As these shifts in fish populations develop, more Southern species such as the Atlantic croaker could become common in New England.
Wareham's Philip Caliri, who operates the Lady J, a charter boat out of Barnstable harbor, can testify to that. On a shark fishing trip last week, 35 miles out to sea, the water temperature was 79 degrees, he said. "And that wasn't even in the Gulf Stream. I would expect the temperature in deep water like that to be about 66 degrees."
Caliri also said he's been finding bonito in Cape Cod Bay, "and that's pretty unusual."
In April, NOAA'a Northeast Fisheries Science Center in Woods Hole released a report on the marine ecosystem for the northeast continental shelf showing that the summer 2011 surface temperature was the highest in 157 years it's been keeping records.
The weather in the last decade is the warmest it has been in a century, according to Jeremy Collie, a biological oceanographer at the University of Rhode Island. "There is a trend in the temperature," he said. "We've had these warmer temperatures for longer." After this year's mild winter, the sea never cooled down, he said. In December 2011, ocean sensors south of the Vineyard registered a water temperature of 68 degrees in the waters next to the continental shelf, a very rare event. And the warming as accompanied by a corresponding jump in salinity.
As summer approaches its end on land, ocean water temperatures are now reaching their peak. And the changing conditions are now being observed year-round.
The warm coastal water in Rhode Island last winter attracted sea herring inshore for the first time. "We had herring trawlers fishing right off Jamestown," Collie said. "People weren't used to that. The warmer water could account for their changed distribution."
Butterfish, which have been scarce in the offshore waters, might simply have moved inshore also, he said.
Janet Nye is the lead author of a comprehensive 2009 NOAA study of 36 fish stocks, including cod, haddock, yellowtail and winter flounder. The study examined survey data from 1968 to 2007 to determine shifts in fish populations caused by ocean warming.
"We found the majority of the stocks were shifting to the north or moving into deeper water over the last four decades," said Nye, who now works as a biologist at the Environmental Protection Agency lab in Narragansett.
Fishermen agreed with her findings, she said. "They had to go further out or into deeper water to get the fish they need."
A more recent study on silver hake, also known as whiting, found the fish moving away to a number of new locations. "They were found in different places but the water temperature was always the same," Nye said.
Read the full story in the New Bedford Standard Times