FISHERY BULLETIN: VOL. 84, NO. 3 



indicating that embryo hatching was probably occur- 

 ring at times other than the peak season. Rodin 

 (1970) reported that egg extrusion occurs from 

 August to September based on the relatively high 

 incidence of recently molted females with new em- 

 bryos. However, Rodin based this on only one sum- 

 mer sample and some of our samples, especially 

 those from the northern area, if examined alone 

 would have also incorrectly led to the same conclu- 

 sion. Our findings, however, are consistent with 

 those for other deep water crabs (L. couesi, Somer- 

 ton 1981b; Geryon quinquedens, Haefner 1978) 

 which have asynchronous or protracted spawning. 

 Asynchronous spawning is also consistent with 

 two of our other observations. First, the larvae of 

 golden king crab, due to their large size and pre- 

 sumably deep habitat, should be relatively insen- 

 sitive to seasonal changes in primary production. 

 Second, adult males and females of golden king crab 

 appear to segregate by depth and this segregation 

 appears to be maintained throughout the year. Such 

 year-round sexual segregation is unlikely for a 

 seasonally reproducing species; however, it is con- 

 sistent with an asynchronous reproducing species 

 if only the reproductively active individuals migrate 

 between depth zones. 



IMPLICATIONS FOR 

 FISHERY MANAGEMENT 



Two of our findings, the latitudinal decrease in the 

 size at maturity and the asynchronous reproductive 

 cycle, pertain to regulations used to manage the 

 golden king crab fisheries in Alaska. 



Commercial harvest of king crabs is restricted to 

 males larger than a minimum legal size (maximum 

 carapace width including spines) which is specified 

 for each species in each management area. These 

 minimum sizes are set at the average size of a male 

 three years after reaching maturity based on the ra- 

 tionale that such a size would preserve sufficient 

 males for breeding even when the exploitation rate 

 is high (North Pacific Fishery Management Coun- 

 cil 1981). Thus, to establish a minimum size limit that 

 conforms to this rule, both an estimate of the size 

 at maturity and an estimate of male growth rate are 

 needed. Unfortunately, we lack sufficient data to 

 estimate the growth rates of golden king crab in any 

 of the three management areas considered here and 

 therefore cannot determine appropriate minimum 

 size limits. However, our estimates of male size at 

 maturity can be used to judge, in a qualitative sense, 

 the adequacy of the current minimum size limits. 

 These size limits and the estimated sizes at matur- 



ity, expressed in terms of carapace length, are as 

 follows: 



Minimum size limit Size at maturity 

 (mm CL) (mm CL) 



The current minimum size limits decrease with 

 increasing latitude, but not in proportion to the esti- 

 mated sizes at maturity. Based solely on the relative 

 magnitude of our estimates, we believe that the cur- 

 rent minimum size limit in the southern area, and 

 perhaps in the central area as well, is too low. 

 However, we believe that the prolonged or year- 

 round breeding of golden king crab would allow 

 males more opportunities for mating than would be 

 possible with a short breeding season; therefore, 

 relative to seasonally breeding king crabs, fewer 

 males would be sufficient for the breeding needs of 

 the population. If this is true, then minimum size 

 limits based on the criteria established for red and 

 blue king crabs may be unnecessarily conservative 

 for golden king crab. 



Commercial harvest of king crabs is also restricted 

 to a legal fishing season specified for each species 

 in each area. Although economic or logistic factors 

 are considered when fishing seasons are established, 

 of primary importance is the timing of the breeding 

 and molting seasons. During the breeding season, 

 females molt while aggregated together with the 

 males (Powell et al. 1973); and if fishing were per- 

 mitted at this time, not only would females be caught 

 in greater numbers, they would also be injured by 

 the fishing gear. During and soon after the male 

 molting season, the recovery rate (ratio of recover- 

 able meat to total body weight) is low; and if fishing 

 were permitted at this time, the value of the crabs 

 would also be low. Since the breeding seasons tend 

 to occur in the late winter and early spring and the 

 male molting seasons occur in late spring, the fish- 

 ing seasons usually begin in the fall. For golden king 

 crab, however, there is no clear seasonality in breed- 

 ing; and adult males and females appear to be 

 spatially segregated throughout the year. Although 

 we lack sufficient data to determine if there is any 

 seasonality in male molting, it appears that there 

 is no compelling biological reason to restrict the 

 golden king crab fisheries to any particular time of 

 the year. Therefore, we believe that, at present, 

 fishing seasons should be determined primarily by 

 what is most convenient or beneficial to fishermen 

 and processors. 



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