To reduce bycatch, think like a fish

To help fishing boats harvest primarily their target catch and minimal amounts of bycatch, it helps to think like a fish. When haddock encounter a net, they tend to swim up into the water column and slowly drift back into the net. Codfish, on the other hand, tend to swim toward the bottom.

Knowing how these two intermingling groundfish species, valuable sources of the whitefish supply, behave differently was critical to the design of a net known in New England as “the Eliminator,” or the Ruhle Trawl, which is engineered with smaller mesh at the top to snag the haddock and huge, eight-foot mesh at the bottom to allow cod to escape.

In testing tows on Georges Bank, the Eliminator caught 83 percent fewer codfish than a conventional net.

The selective gear was designed among a partnership comprising Jon Knight, a net maker at Superior Trawl in Point Judith, R.I., father-and-son fishermen Phil Ruhle Sr. and Jr., and James O’Grady, also from Point Judith, and scientists from the University of Rhode Island. The Eliminator was re-named to the Ruhle Trawl in memory of Phil Ruhle Sr., a tireless advocate for the fishing industry who was lost at sea in July 2008.

Use of the net allowed fishermen during the 2007-2008 groundfish season into certain closed areas of Georges Bank to harvest abundant haddock without hammering struggling cod stocks, providing seafood buyers with more haddock and behind-the-scenes assurance that it had been caught without harming the cod biomass. The Eliminator won a $30,000 grand prize in 2007 in the World Wildlife Fund’s (WWF) International Smartgear competition.

This year, the competition offers a grand prize of $30,000, two $10,000 runner-up prizes and a $7,500 special prize to an idea that reduces bycatch in tuna fisheries, via a partnership with the International Seafood Sustainability Foundation. WWF has identified tuna sustainability as its top global fisheries conservation priority.

Click here to read the rest of the story on bycatch, which was written by SeaFood Business Contributing Editor Lisa Duchene and appeared in the magazine’s May issue. 


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