Of Cod and Warming

During colder winters, fishermen in these parts could count on schools of cod pouring south off Georges Bank

    When a tornado, or tsunami, comes from out of the blue, it rattles our collective nerves. But it’s also unsettling when what we expect of nature fails to occur.

    During colder winters, fishermen in these parts could count on schools of cod pouring south off Georges Bank and taking up residence within range of local boats. There have been lean years before. After all, the folks at the Northeast Fisheries Science Center at Woods Hole, Mass., remind us that southern New England, Block Island, and Montauk are at the southern edge of the Georges Bank cod population, even in winter.

    And, it should be remembered that low cod populations over all have resulted in dramatic quota reductions. The once vast schools of cod, Gadus morhua, were the foundation of New England settlements beginning in the 17th century. Cities including Gloucester, New Bedford, and Boston owe their existence to cod. Mark Kurlansky informs us in “Cod: A Biography of the Fish That Changed the World” that Norse and Basque fishermen sailed across the Atlantic to reap the cod resource centuries earlier.

    During the 1980s and much of the ’90s, the Gulf of Maine cod stock, and the population living on Georges Bank to the south and east, kept pace with the ever-increasing fishing pressure. In addition to a robust winter sport fishery, Montauk Harbor was also home to a number of set-line fishermen who successfully targeted cod using long lines set along the bottom with a series of buoyed hooks baited with clams. Then the bottom dropped out. Capt. Rick Etzel of Montauk was one charter captain who set cod lines in winter. Last week he said, “When they talk about how many ling they’re catching, you know the cod is way off.” Ling, a cod-like species, is often more numerous, but considered a poor substitute for the real thing.

    The New England Fishery Management Council, which oversees the cod resource, reduced quotas again and again in an effort to spark a recovery. Last year, quotas for both stocks were reduced, 80 percent in the Gulf of Maine, and 61 percent for the Georges Bank stock that our local fishermen target in winter.

    But fishing pressure alone may not account for what Montauk’s Viking Fleet of party boats and others are seeing, or not seeing, this season.

    “We had really good fishing from the end of January to the middle of February, but then it fell apart. We’re still catching some, but not of any size. It’s good for 20 minutes to an hour before light, then the dogs come,” Capt. Carl Forsberg said on Monday — “dogs” being dogfish, the bait-stealing bane of bottom fishermen.

    A warmer-than-usual winter might explain it, but Captain Forsberg said a cold winter, like this one, without cod is unusual. Something else is going on. For one thing, the ocean temperature is not all that cold despite the teens and single digits onshore.

    A joint study undertaken by United States and Canadian scientists found that climate change, more than a species’ biology, has caused shifts in where and at what depths it is found. A paper that appeared in the Sept. 13, 2013, edition of the journal Science proposed that “climate velocity” — the rate and direction of climate shifts in a particular region — explains the shifts in species distribution.

    The U.S.-Canadian study found that ocean temperatures have risen and circulation patterns have changed on the Continental Shelf in the Northeast in recent decades, and these changes have redistributed zooplankton essential to species including cod. So marked are the changes that an ecosystem advisory was published by the Northeast Fisheries Science Center last April.

    This is not to say we should stay onshore. Exceptions are always found within mega-trends. Captain Forsberg said that while cod fishing has slowed, his anglers continued to bring home a fish dinner or two or three. The mystery of the sea is perhaps its greatest protection.