With fishery regulators poised to impose devastating cuts Thursday on the New England fleet, blame for the disappearance of once-abundant cod and flounder populations is shifting from fishermen to a new culprit: the changing ocean.
Warming waters and an evolving ocean ecosystem possibly related to man-made climate change are contributing to the anemic populations, not just decades of overfishing, government officials say.
Researchers are just beginning to understand how the vast Gulf of Maine is responding to global warming and exactly what will happen to fragile fish populations. They acknowledge they don’t know whether prized cod and flounder stocks will ever rebound — and if they don’t, what species will take their place.
“While we are not blaming fishermen, this is not good news,’’ said John Bullard, the National Oceanic and Atmospheric Administration’s regional chief. “We can control overfishing — it’s hard but we can do it — but how do you control this?”
The only option, Bullard and other regulators say, is to dramatically restrict fishing to give the bottom-hugging fish any hope of a comeback.
The New England Fishery Management Council could vote Thursday on cutting catch quotas by up to nearly 80 percent for some stocks of cod, as well as cuts to other species. To ease the pain, the council, a governmental body made up fishermen, industry representatives, state officials, and environmentalists, will also decide whether to open more than 5,000 square miles of conservation area now closed to most fishermen.
Large numbers of fishermen are expected at the meeting in Wakefield, hoping to persuade the council not to take such drastic measures. Environmentalists are also planning to show up, to urge conservation.
Fishermen are struggling to comprehend how the sacrifices they made in the last decade to idle boats and catch fewer fish were for naught. Only four years ago, scientists said cod populations were healthy and growing, a rosy assessment that unraveled last year when researchers discovered serious errors in their analysis had led them to overestimate Gulf of Maine cod by nearly 300 percent.
While many fishermen are angry, others are resigned — because like the scientists, they can’t find the fish, either. Eight months into the fishing year, the entire fleet has caught just 44 percent of this year’s cod quota.
“I don’t know where the fish are,’’ said Jim Ford, an East Kingston, N.H., fisherman who catches cod out of Gloucester and Newburyport.
Temperature gear on his net that drags along the sea floor is recording temperatures of 50.5 degrees. “That is almost unheard of, we should be in the mid-40s,’’ Ford said. “It is too warm.”
Water temperatures this year in the Gulf of Maine were the highest ever recorded, the result of a spike in an ocean warming trend seen since 2004, according to research led by the Northeastern Regional Association of Coastal and Ocean Observing Systems.
While the waters off the Eastern Seaboard have warmed slightly since the late 1800s, there have been cycles of cooling and warming, and scientists are not sure whether the Gulf of Maine’s warming is from natural cycles, climate change, or a combination of both.
Fish aren’t waiting around for the answers.
‘That is almost unheard of, we should be in the mid-40s. It is too warm.’
NOAA research shows that about half of 36 fish stocks they analyzed in recent years, including cod, flounder, and lesser-known species, have been shifting northward or into deeper waters in the last four decades. While locally caught Atlantic cod are disappearing from restaurants and stores, other fish that thrive in warmer water, such as Atlantic croaker, could take their place. But it’s unclear if fishermen will be able to make as much money from these species.
The timing of spring plankton blooms — the foundation of the marine food web — may also be shifting, scientists say, coming earlier in the spring, as it did this year. Plankton changes, combined with rising ocean temperatures, could affect the success of young marine life because so many species time their spawning to the spring bloom.
Fishermen, meanwhile, are also seeing profound changes, such as dramatic increases in skates and the voracious dogfish, a small shark that may be eating vast amounts of cod.
Overfishing is still an important factor, scientists say. Decades of overfishing have weakened populations so greatly they may not be able to withstand climate change as well.
“You don’t want to hit the system so hard when it’s down,’’ said Les Kaufman, a Boston University biology professor who studies fish.
He said the stocks may recover, but it may not be on a time scale fishermen want.
Virtually everyone agrees the meeting Thursday will be a painful one.
The Northeast Seafood Coalition, a Gloucester-based industry group, says the fish council could institute less severe catch limits to keep fishermen in business while remaining in compliance with a law that requires strict fish stock rebuilding timetables.
Yet other fishermen, while acknowledging there are problems with the science, say they want managers to be precautionary — and add that cuts may not be as drastic as they sound because so many fishermen can’t catch their quota anyway.
“There is plenty of evidence that things are changing very quickly, and a lot of these changes are complex and somewhat unpredictable,’’ said Tom Dempsey, policy director for the Cape Cod Commercial Hook Fishermen’s Association.
“In many ways, we need to reduce our quotas, but in my mind, what I keep coming back to is with many of the quotas, we are not even coming close to reaching them already.”Beth Daley can be reached at email@example.com. Follow her @Globebethdaley.