Cod bycatch in otter trawls and in longlines with different bait types in the Georges Bank haddock fishery

In the Northwest Atlantic, bycatch of depleted groundfish stocks in the haddock fishery on Georges Bank is an ongoing concern. In recent years, this fishery on the American side of Georges Bank has been limited by high bycatch rates of cod. Considerable conservation engineering work has been done to address the problem, including experiments with different longline baits and modifications to otter trawl gear. Fabricated baits have shown promise for increased selectivity when longlining, but it has sometimes been difficult to establish whether low cod catch rates with fabricated baits have resulted from bait selectivity or from a low abundance of cod in the area. In this study, we compare catch rates of cod and haddock between otter trawls and longline gear in experimental and commercial fishing on Georges Bank in the summer of 2005. We also compare cod bycatch rates among longlines baited with squid, herring, or fabricated baits (mainly Norbait 700E) in Georges Bank Closed Area 1, from October 2003 to June 2005. Records from the Northeast Fisheries Observer Program were combined with data collected by the Cape Cod Commercial Hook Fishermen's Association (CCCHFA), and compared using generalized linear models. In the Eastern US-Canada Resource Sharing Area (EUSCA) in the summer of 2005 catch of cod per haddock by weight was significantly lower when fishing with longline gear (0.008-0.045 kg cod per kg haddock) than with otter trawl gear (0.059-0.826 kg cod per kg haddock), in all months and areas. Cod bycatch rates were also significantly lower for longlines fishing for haddock than for otter trawls fishing for groundfish species other than haddock. In Closed Area 1, statistically significant differences in cod to haddock ratios were found between baits, with squid catching the highest amount of cod, fabricated baits catching the lowest amount, and herring at an intermediate level. The development of fishing methods that minimize cod bycatch is a high priority in many regions of the North Atlantic. These results indicate that longlines with fabricated bait have the potential to maintain a very low catch of cod while fishing for haddock. (C) 2008 Elsevier B.V. All rights reserved.