A recent court decision in Washington DC upholds controversial fishing closures in the Gulf of Maine. The closures were established last year to protect fragile fisheries—and they weren’t the first. After the New England cod fishery collapsed in the mid nineties, an area of ocean roughly one fifth the size of New Hampshire was designated off limits to ground fishing. But even after seven years without trawling in this area of the Gulf of Maine, the number of cod is still low. Many worry that there’s something else going on below the surface that could limit the fish population from bouncing back. As NHPR’s Kerry Grens reports, that something is likely to be found at the bottom of the ocean.
The bottom of the Gulf of Maine varies from rippled stretches of sandy plains to jagged fields of boulders.
Dr. Les Watling from the University of Maine says it’s this complex, rocky zone in the gulf that’s especially important for young cod.
Watling: They survive better in these areas of complex habitat. And that complex habitat is due to the fact that you have sponges and anemones and other things that actually provide hiding spaces and with the little invertebrates that live with them provide food for these baby cod.
When trawlers come through areas like this, they disturb the bottom, rolling over boulders and crushing or displacing animals.
By the time scientists observed this, and learned how cod rely on this habitat, the fishery was about to collapse.
Watling: Because there was no habitat information about young cod at all, all this habitat you could argue was critical for the survival of young cod was being trawled over by rock hopper gear. I’m not surprised that the fishery collapsed, totally. And maybe it will be collapsed for a really long time. Because so much bottom habitat has been so completely altered.
So Dr. Jeb Byers at the University of New Hampshire asked the question, well, how long will it be before the bottom habitat comes back?
To answer this he went out to the Western Gulf of Maine marine reserve, where trawling was prohibited seven years ago.
Byers and a student sent down a few cobbled, concrete slabs to the bottom to mimic the rocky seafloor.
They then waited to see how long it would take for animals to take up residence on the panels.
Byers: After four months there was almost nothing on these recruitment panels. But even after we let some of these stay for a year and in some cases some of these have been down for a year and a half you can see here we get very limited development of the communities down there.
It didn’t matter if the panels were inside or outside the reserve where there might be more or less fish—there was not a lot of growth.
Byers had expected to pull up panels teeming with life.
Byers: So we were very surprised by this. Everybody we had talked to, including the fishermen before we put this, told us they would be loaded with stuff. But because we have this very slow recovering system, that it’s going to be a long time before that system gets back to normal gets back to creating that structure and creating that prey base, which is important for the fish.
Important though it may be, not everyone agrees on how delicate life at the bottom is.
Fisherman and New England Fisheries Management Councilman David Goethel doesn’t think that trawling is that damaging to the habitat.
Even after extensively trawling an area, he still finds fish.
Goethel: And that would make me think—again, this is more intuition than scientific fact—that there must not be anything permanent going on here if these fish keep coming back to these areas year after year after year.
Goethel would like to see definitive data on a missing link among all this habitat research: does a slowly growing bottom mean a slowly recovering fishery?
Goethel: It may kind of a cold and crass thing to say. But if there are some invertebrates that don’t recover quite as fast and they don’t have any effect on the fisheries, while it’s unfortunate it may not be catastrophic.
Researchers are trying to find those links between how the seafloor recovers and what that means for the health of the fishery.
But with bottom creatures growing at such a slow pace, it will be long time before they can find out.
For NHPR News, this is Kerry Grens.
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