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Warmer Water Driving Fish Farther Off New England

November 17, 2009 - Fishermen have known for years that they have to go farther and farther from shore to find cod, haddock and winter flounder.

A new federal study documenting the warming waters of the North Atlantic confirms that they're right, and that the typical catch could eventually be Atlantic croaker, red hake and summer flounder – fish normally found to the south.

"Fishermen are businessmen, so if they have to go farther and deeper to catch the fish that we like to eat, eventually it won't be economical to do that," said Janet Nye, the lead author of the study. "It just won't be in your local seafood store, or maybe it will be more expensive."

Nye, a fishery biologist at the Northeast Fisheries Science Center in Woods Hole, Mass., said, "There will be a natural, hopefully slow, switch to different seafoods."

For the study, which appeared Oct. 30 in the journal Marine Ecology Progress Series, Nye and three other biologists analyzed water temperature trends from North Carolina to the Canadian border from 1968 to 2007. They then looked at fish survey data collected each spring and assessed where the fish were caught and how abundant they were.

The researchers looked at the familiar New England species, as well as lesser-known fish such as longhorn sculpin and blackbelly rosefish.

Of the 36 stocks studied, the distribution range of 24 of them had changed in unison with water temperatures that have been rising off the Northeast since the 1970s.

That temperature rise doesn't sound like much – less than half a degree Fahrenheit, on average – but it has been enough to cause fish to move slowly to areas with temperatures more to their liking.

The greatest movement was by the blackbelly rosefish, which moved more than 200 miles to the northeast during the years studied. Among commercial species, movements of more than 100 miles were observed for southern stocks of yellowtail flounder and red hake, as well as American shad and alewives.

Some fish made little movement to the north but moved to deeper waters, where temperatures are lower, the report said.

Small-boat fishermen on Cape Cod caught most of their haddock, flounder and cod close to shore 20 years ago, said Tom Dempsey of the Cape Cod Commercial Hook Fishermen's Association. Now, they have to go as far 100 miles offshore to find those fish.

At the same time, he said, Massachusetts fishermen are catching more fish traditionally found in the mid-Atlantic – Atlantic croaker, in particular, which usually is caught off Virginia and North Carolina.

"How much of that is directly impacted by climate change is hard to get a handle on," Dempsey said. "There are a number of other factors ... one being overharvesting in inshore areas and, subsequently, ecological changes as inshore areas have become dominated in a lot of areas by spiny dogfish populations."

The study is one piece of the puzzle in figuring out the factors that influence ocean species, said Jason Link of the National Oceanic and Atmospheric Administration, a co-author of the study.

While the report says climate change is the driving factor, Link said influences such as fishing and long-term cycles in ocean temperatures and atmospheric conditions play a role.

"We're looking at how much of this movement to colder waters is perhaps related to the environment as opposed to how much is due to fishing," he said. "I don't think this paper totally answers that question."

By CLARKE CANFIELD, The Associated Press November 13, 2009


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