Ghost fishing by Tanner crab (Chionoecetes bairdi) pots off Kodiak, Alaska: pot density and catch per trap as determined from sidescan sonar and pot recovery data

Sidescan sonar was used to locate 189 putative lost crab pots in a 4.5 km(2 ) area of Chiniak Bay, near Kodiak, Alaska. Subsequent observations of 15 s uch objects by submersible and ROV verified that they were indeed crab pots . In 1995 and 1996, 147 pots were recovered from the surveyed and adjacent nonsurveyed areas by grappling, and their condition and contents were exami ned. Tanner crabs, Chionoecetes bairdi, were the most abundant organism, wi th 227 found in 24 pots (16% frequency of occurrence); sun-flower sea stars (Pycnopodia helianthoides) were the most frequent (42%) occupant and secon d most abundant (189 in 62 pots). Octopuses (Octopus dofleini) were signifi cantly associated with pots containing Tanner crabs. Occurrence of crabs in pots was primarily a function of background crab density and differed betw een the surveyed and nonsurveyed areas. Recently lost pots (< 1 yr old) had significantly more male crabs, significantly larger male crabs, and contai ned seven times more total crabs than older pots (those lost two or more ye ars prior to recovery). The proportion of pots with damaged webbing increas ed with pot age, but holes in pot webbing did not significantly affect catc h per pot.