The reason it has been so difficult to restore New England’s commercial groundfishery without completely bankrupting New England’s commercial fishermen can be summarized in a few sentences:
*More than a dozen species comprise the fishery and inhabit the same layer of water near the ocean floor.
*Some of these stocks are abundant; some are not.
*Most fishermen rely on trawl gear, a wide-mouthed net towed along the bottom.
*Trawl nets have difficulty distinguishing between plentiful and scarce species and often catch both.
*The Sustainable Fisheries Act requires managers to protect fish that are most at risk for overfishing meaning, even if the majority of stocks are up, if just one stock is down, fishing regulations must be tightened.
Consider the recent increase in the region’s haddock and pollock populations. Despite robust numbers in the Gulf of Maine and Georges Bank, managers have still been forced to implement drastic restrictions in order to protect cod, which continue to struggle.
Some have suggested that trawl gear be banned altogether, to eliminate the incidental mortality of non-targeted species (bycatch). But since the purpose of natural resource management is not only to protect fish, but also to provide an opportunity for people to make a living catching them, abolishing a fundamental component of the industry seems a bit drastic and naïve. (Imagine the uproar if all cars were banned to cut down on greenhouse gas emissions.)
Here as elsewhere, technological innovations have offered a sort of middle road. Indeed, in some southern water shrimp fisheries, separator devices have almost entirely eliminated bycatch of threatened turtles. Of course, distinguishing a turtle from a shrimp is quite different than sorting a haddock from a cod, which are about the same size, eat basically the same food, and live in the same habitat. But, despite all of these similarities, one of their most basic functions differs: they swim differently.
In the early 1980s, researchers from Scotland shot underwater video that revealed distinct behavior of cod, whiting and haddock when approached by a trawl net. Haddock tend to swim above the net in order to escape and cod tend to swim below it. Whiting swim somewhere in between. This finding led engineers to collaborate with fishermen on a net design that exploited the difference in swimming behavior.
Various prototypes have been developed for a handful of species in New England’s fishery as well. The development of the “B” days-at-sea concept in 2003 underscored the need for an effective separator trawl for the haddock fishery. So-called “B” days were established to allow fishermen to target abundant species such as haddock and pollock while allowing scarce species like cod to recover. The idea is that “B” days in combination with effective conservation gear could sustain the fleet economically while troubled stocks rebuild.
Last year, Dr. Pingguo He of the University of New Hampshire teamed up with Maine fishermen Vincent Balzano and Tim Eddy to build a trawl suitable for targeting haddock and pollock inshore. Balzano’s vessel NORTH STAR, a 45-foot trawler, was utilized for the sea trials with Eddy’s vessel PERSISTENCE, also a 42-footer, fishing alongside with traditional gear.
It is important to develop selective gear for this habitat because inshore vessels are limited in the distances they can travel to reach plentiful stocks, and especially feel the burden of regulations. Cod also heavily utilize the inshore area to feed and spawn.
The key feature of the new trawl will be a high headline opening, which may be assisted by the use of kites and raised footrope with long drop chains to provide opening for cod and bottom-dwelling species.
“The substantial increases in haddock and pollock biomass in Gulf of Maine, and much slower increase in cod stocks, provide basis for use of such trawls in the multispecies fishery to reduce fishing pressure of cod,” said Dr. He. The initial design was completed in collaboration with industry partners, and flume-tank tests were conducted at Memorial University in Newfoundland. The gear was adjusted based on the results and field trials began off Portland in June.
“Like any gear we’ll need to make further refinements, but some of the catch rates in the early trials were as good as I’ve seen in ten years,” said Balzano.
The primary innovation of the net design is the use of long drop chains (3 to 5 feet above the seafloor) between the fishing line and the sweep, creating a space for cod, flounders and other bottom-dwelling animals to escape. The trawl also incorporates large meshes in the wings and belly to reduce drag of the net and allow the same vessel to tow a high opening trawl.
Kites were added near the wing-ends and headline to help expand mesh, which tends to close under strain.
A similar approach has been used successfully in other multispecies fisheries. In Newfoundland’s shrimp fishery, drop chains are raised as much as three feet to reduce bycatch of groundfish. In New England’s whiting fishery, variations on the concept have been experimented with to reduce the capture of flounder. And long drop chains were also applied to the squid fishery. This study will add to the body of gear research that could prove to be essential in protecting at-risk fish and at-risk fishermen.
An annual progress report is posted at www.northeastconsortium.org.
Mike Crocker is the editor of Collaborations, a report on scientific research conducted between scientists and fishermen. For a free subscription email mike@namanet.org.