398 



Fishery Bulletin 98(2) 



density of 943 crab/km^ in the sonar-surveyed and 

 nonsurveyed study areas combined. Relative CPP of 

 pots recovered during our study reflected the traw- 

 lable densities in each bay; CPP was 2.70 for pots 

 in Chiniak Bay, 0.04 in Kalsin Bay, and in Middle 

 Bay. For both the 1996 trawl survey and our pot 

 retrieval studies, the Chiniak area had the highest 

 density of Tanner crabs, with Kalsin Bay second, 

 and Middle Bay last. Chiniak Bay is also a site 

 where female Tanner crabs aggregate continuously 

 and form high density spawning aggregations in the 

 spring (Stevens et al., 1994). 



Knowledge of the abundance of lost pots and num- 

 bers of crabs in these pots is required to estimate 

 the impact of ghost fishing, but are not enough in 

 themselves. A more complete assessment of ghost 

 fishing by crab pots will require estimates for rates 

 of ingress, egress, as well as mortality rates of crabs 

 and studies on the degradation rates of biodegrad- 

 able twine and other structural components of crab 

 traps. Improved enforcement of existing regulations 

 could help reduce ghost fishing. Current estimates of 

 total pot losses are just guesses but could be substan- 

 tially improved by surveying fishermen or requiring 

 them to report pot losses. 



Acknowledgments 



We are indebted to Capt. Gary Edwards of the FV 

 Big Valley, who built and operated the grappling 

 devices during the targeted and nontargeted por- 

 tions of this study. The pilot study was conducted 

 with the aid of Capt. Ron Kutchick, of the ADF&G 

 RV Resolution. We also thank the many "ghost (pot) 

 busters" who assisted us in our effort, including J. 

 Haaga, R. Otto, R. Macintosh, P. Cummiskey, and 

 K. Phillips. This report benefited from the thought- 

 ful comments of Bob Wilbur and two anonymous 

 reviewers. This study was partially funded by the 

 U.S. Army Corps of Engineers. Funding for use of 

 sidescan sonar was provided by the West Coast and 

 Polar Regions Undersea Research Center, Univer- 

 sity of Alaska, Fairbanks, AK. 



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