ship's rail. At the time of pot retrieval, dead crab found 

 in the pots were inspected to determine whether such in- 

 juries might have caused their deaths. 



Unbailed Pot Experiment 



Escape rates were obtained by allowing pots contain- 

 ing tagged crab to soak for various intervals before 

 retrieval. Tagged crab missing from the pot when it was 

 recovered were presumed to have escaped. Their subse- 

 quent recovery in the commercial fishery was compared 

 with conditions of those released directly into Chiniak 

 Bay. Recovery rates were expected to be similar if no in- 

 jury resulted from confinement or escape effort. 



Box Shaped Pots 



During 1975, 60 tagged crab (30 undersize and 30 legal 

 size) were placed in each of 24 "standard" pots (Fig. 2). 

 Groups of three pots were lifted after 1, 2, 3, 4, 7, 10, 15, 

 and 16 days. Six groups of four pots, set in 1974, did not 

 have a prescheduled retrieval date except for the first 

 four pots after 4 days. Since we did not know what escape 

 rate to expect, each pot retrieval day (after the first) was 

 based upon the observed escapement at that time. We 

 anticipated that retrieval for the six groups might take 40 

 days or more. Instead, they were lifted after 4, 6, 8, 10, 

 14, and 15 days. 



Fiberglass Pyramid Pots 



This test was limited in scope because our objective 

 was simply to determine whether the escape rate was dif- 

 ferent from that of standard pots. Thirty undersize and 

 30 legal-size tagged crab were placed in each of 12 pots 

 grouped in pairs for 1-, 2-, 3-, 4-, 10-, and 16-day soaks. 



Radical Pyramid Pots 



Numbers of crab and soak durations were the same as 

 for the fiberglass pyramid pots. Two tagged crab were 

 observed floating out of the large top opening in these 

 pots just after the pots were pushed into the water. It is 

 not likely many escaped in this way because the pots 

 were heavier on the door side and tended to descend with 

 one side up preventing crab from floating out the open- 

 ing. After each pot reached the sea floor, tension was 

 taken up on the buoy line to upright the pot. In spite of 

 this maneuver, several radical pots remained on their 

 sides (indicated by stained web and steel), and escape- 

 ment promptly approached 100' c as crab could walk free- 

 ly out the misplaced opening. Such "invalid" pots were 

 deleted from the experiment. 



Conical Snow Crab Pots 



The Japanese-type pot was considerably smaller than 

 the other pots. Consequently, only 15 undersize and 15 

 legal-size tagged crab were placed in each one (three 



groups of four pots were attached to groundlines at 18-m 

 (10-fathom) intervals with single buoylines to the sur- 

 face). As with the standard pots used in 1974, only the 

 first group lift was scheduled after a 4-day soak. The ini- 

 tial escapement was of such magnitude that the remain- 

 ing groups were lifted after 8-10 days on the bottom. 



Crowding Experiment 



Occasionally, pots are retrieved that tire completely 

 filled with crab. It is difficult to imagine how 200 or more 

 adult crab could enter a pot or, once inside, effectively 

 escape. The effect of crowding upon escape was tested in 

 two groups of three standard box-shaped pots by placing 

 75 undersize and 75 legal-size tagged crab in each. A few 

 more than the 150 crab could have been accommodated 

 in the pots, but with more than that number some indi- 

 viduals could have fallen out through the tunnel during 

 the setting process. 



Baited Pot Experiment 



Our objective was to determine whether bait (chopped 

 herring or dead king crab) would motivate tagged crab to 

 remain in pots longer than they would have otherwise, 

 thereby causing increased mortality. Bait is either in the 

 derelict ijots at the time of their loss or is formed when- 

 ever animals die in the pots. Although it is an accepted 

 fact that crabs are attracted to bait consisting of fish 

 pieces, we did not know if king crab in baited pots would 

 remain longer than those in unbaited pots or if dead king 

 crab attract living crabs. Research conducted by Han- 

 cock (1974) with Australian lobsters gave indications 

 that dead members of that species repel their living 

 counterparts. 



Standard baited pots were treated in a manner simi- 

 lar to that in experiments with unbaited pots. In one test, 

 chopped pieces of Pacific herring, Clupea harengus pal- 

 lasi, were placed in 1-qt plastic containers that had per- 

 forations to allow dispersion of solutes. These commer- 

 cial style containers were hung in each of six pots with 60 

 tagged crab and set near other test pots. Soak periods 

 were 1, 3, and 7 days. A second group of six standard pots 

 were each filled with 60 tagged crab along with 15 freshly 

 killed crab of assorted sizes. New crab entering these pots 

 and those entering unbaited pots were recorded as were 

 those tagged crab which remained — to provide an esti- 

 mate of movement into and out of the pot groups. 



Confined Crab Viability Experiment 



Duration of confinement in pots was tested in two ways 

 to learn if duration caused mortality or otherwise af- 

 fected crab survival, even though the crab left the pots 

 before death. First, crab mortalities that occurred dur- 

 ing the various soak periods were tabulated and com- 

 pared. Secondly, returns of tags from the commercial 

 fishery for free-release crab served as controls and were 

 compared with recoveries of crab that had escaped from 

 the various test ptots. A significant difference in recovery 



