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John B Penson, Jr, 

 Ernest O, Tetty 

 Wade L Griffin 



Department of Agricultural Economics 

 Texas A&M University 

 College Station, TX 77843-2124 



APPENDAGE II^JURY IN DUNGENESS 



CRABS, CANCER M AGISTER, IN 



SOUTHEASTERN ALASKA 



The Dungeness crab, Cancer magister, is com- 

 mercially important along the western coast of 

 the United States. Like many decapod crus- 

 taceans, it can autotomize and regenerate ap- 

 j>endages to heal wounds and limit injury. 



Studies of appendage injury may be useful in 

 assessing the physical condition of crustacean 

 populations and the impact of fishing on commer- 

 cially important species. Incidences of appendage 

 loss in the field have been reported for species of 

 crabs other than C. magister (McVean 1976; 

 McVean and Findlay 1979; Needham 1953). Ap- 

 pendage loss was studied in adult Dungeness 

 crabs in Washington (Cleaver 1949) and Oregon 

 (Waldron 1958) and for juvenile crabs in the Co- 

 lumbia River estuary (Durkin et al. 1984). 



In this study we examined adult Dungeness 



crabs in southeastern Alaska to determine the 

 incidence of missing, regenerating, and damaged 

 appendages. Temporal incidence of appendage in- 

 jury was compared to the molting and mating 

 periods of the crabs and to the commercial fishing 

 season for Dungeness crabs. 



Materials and Methods 



Adult Dungeness crabs were collected from Icy 

 Strait and the Excursion Inlet fjord near Glacier 

 Bay, AK (lat. 135°30'N, long. 58°25'W), from May 

 through November 1984-85. Data were obtained 

 by monthly surveys of commercially caught 

 crabs. Crab pots (Waldron 1958) were set at 

 depths of 7 to 20 m and remained in the water for 

 3 to 11 days. All crabs were held in live tanks 

 (<24 hours) before they were measured on board 

 ship. In southeastern Alaska, pots are equipped 

 with escape rings to permit release of crabs with 

 carapace widths <165 mm, but sublegal-sized 

 crabs are often found in the catch. 



Carapace width (excluding the 10th anterolat- 

 eral spines), wet weight, and sex were recorded 

 for each crab. Carapace condition was graded as 

 soft-shell (recent molt), new-shell, worn-shell, or 

 skip-molt (Somerton and Macintosh 1983). The 

 number and identities of missing, damaged, or 

 regenerating chelipeds and walking legs were 

 recorded. An appendage with a cracked cuticle or 

 missing dactyl was considered damaged. Ap- 

 pendages smaller in length and diameter than 

 intact appendages were designated regenerating. 

 Combined missing, damaged, and regener- 

 ating appendages are referred to as injured 

 appendages. 



Interrelationships between variables were de- 

 termined with Pearson correlations (SAS 1985). 

 Means were compared with Student's ^ -tests, and 

 chi-square analyses were used to determine if 

 multiple autotomies occurred by chance (Steel 

 and Torrie 1960). Data are presented as means 

 ± 1 standard error of the mean. 



Results 



Males comprised 65% and females 35% of the 

 878 Dungeness crabs examined. Average cara- 

 pace widths were 169 ± 0.6 and 159 ± 0.7 mm for 

 males and females, respectively. Wet weights 

 were 1,102 ± 9 g for males and 884 ± 14 g for 

 females. The greatest number of female crabs was 

 caught in July, and the greatest number of males 

 in August. 



156 



FISHERY BULLETIN; VOL 86, NO, 1, 1988. 



