Stevens et al : Ghost fishing by Tanner crab pots 



391 



Figure 1 



Chart of Chiniak Bay. Kodiak Island, Alaska, showing position of pots discovered by sidescan 

 sonar survey. Inset shows location of Chiniak Bay on Kodiak Island. 



tence use, whereas pots coded as "fair," "poor," or 

 "very poor" were assumed to have been lost more 

 than one year. Commercial fishing for Tanner crabs 

 around the northeast quadrant of Kodiak Island has 

 been closed since January 1994, and for king crab 

 since 1983'^; therefore no commercial crab pots have 

 been used in the region since that time, although 

 subsistence pots are still allowed. Therefore, recov- 

 ered pots would have to have been lost at least 2 

 years previously (prior to April 1993), unless used 

 for subsistence purposes. Since 1977, the state of 

 Alaska has required that all crab pots contain an 

 18-inch (45.7-cm) segment of biodegi-adable twine 

 that degrades within 90 days (Alaska Statutes, 1996 ). 

 For this reason, all pots were examined for the pres- 

 ence and condition of degradable twine. However, it 

 was not our goal to study the effectiveness of biode- 

 gradable twine because suitable control pots were 

 not available. Furthermore, absence of biodegrad- 

 able twine was inconclusive when holes were pres- 

 ent in the webbing, because it could have indicated 

 either that the twine had already degraded or that 

 no twine had been present and holes resulted from 

 some other cause. 



3 ADF&G (Alaska Dept. Fish and Game). 1996. Annual man- 

 agement report for the shellfish fisheries of the Westward 



Region, 1996. Regional information report 4K97-41. 

 211 Mission Rd. Kodiak, AK 99615. 



ADF&G, 



For all crabs found in pots, carapace width (CW) 

 was measured to the nearest mm with vernier cali- 

 pers across the widest part of the carapace, exclud- 

 ing spines. Abundance of all other species inside the 

 pot and size of commercially important species was 

 also recorded. These procedures were repeated for 

 each pot. All retrieved pots had their webbing cut 

 and were disposed of at a location designated by the 

 USAGE and the KIB. 



Targeted study 



From 17 June to 18 July 1996, the procedures devel- 

 oped during 1995 were again used, with some mod- 

 ifications. The study was conducted by biologists 

 aboard the contracted fishing vessel Big Valley. Pots 

 were randomly selected for retrieval from the list of 

 putative pot positions. Gear used for this study was 

 a grappling beam made of 6.4 m long, 5.1 cm diame- 

 ter steel pipe, and was pulled by a braided steel wire 

 cable with a synthetic bridle. A 183-m tag line and 

 buoy were attached to the beam to retrieve the device 

 if the tow line was broken. Attached to the beam 

 were six gi-apples, each consisting of a 1.2-m long 

 "V" bar with two 30-cm arms welded so as to project 

 forward and down. After the first week, a second set 

 of arms was welded to the gi-apples facing upward, 

 and on 8 July 1996, 7.6-cm barbs were welded to 

 the ends of each arm to prevent snagged lines or pot 



