than the inclusion of measurements from regenerat- 

 ing chela. 



Results and Discussion 



For both sexes of blue king crab, estimates of the 

 size at sexual maturity were largest at Pribilof 

 Islands, smallest at St. Matthew Island, and inter- 

 mediate between these extremes at Olga Bay and 

 Prince William Sound (Tables 1, 2). Precision in the 

 estimates of the size at maturity of blue king crab dif- 

 fers markedly between sexes. For females, the average 

 standard deviation was 0.45 mm, whereas, for males, 

 the average standard deviation was 10.93 mm, about 

 24 times larger. Because of this difference, the es- 

 timates for females differed significantly (Z test, 

 P<0.5) between all areas, but the estimates for males 

 did not differ between areas even though their range 

 was nearly double that of females. 



Much of the imprecision in the estimates of male 

 size at maturity is the result of the pattern of relative 

 growth. Standard deviation of an estimate of male 

 size at maturity depends largely on the angle a l ;. hich 

 the two phase lines meet. As the included angle in- 

 creases, uncertainty in the position of each phase line 

 is progressively magnified in the uncertainty of the 

 estimate of the size of maturity. Species, such as blue 

 king crab, which exhibit a large angle between phase 

 lines, inherently have a large standard deviation. 



Future studies of male crabs with a similar pattern 

 of relative growth should insure that samples include 

 a broad range of sizes, because this will minimize the 

 standard deviation of the estimates of size at maturi- 

 ty. The relationship between size range and standard 

 deviation is exemplified by the two extreme cases ex- 

 amined here. The Olga Bay sample, which produced 

 the smallest standard deviation, included individ- 

 uals as small as 1 2 mm, whereas the Prince William 

 Sound sample, which produced the largest standard 

 deviation, included no individuals smaller than 72 

 mm. 



Acknowledgments 



We thank C. M. Lynde, B. A. Megrey, R. S. Otto, and 

 D. G. Chapman for reviewing the manuscript, E. 

 Monk and J. Bowerman for assisting in the field sam- 

 pling, and A. Kimker, Alaska Department of Fish and 

 Game, for allowing the senior author to accompany 

 him on a survey cruise to Prince William Sound. 

 Research was supported by NORFISH, a marine 

 research project of the University of Washington Sea 

 Grant Office and the National Marine Fisheries Ser- 

 vice, NOAA. 



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David A. Somerton 



Center for Quantitative Science in Forestry, 

 Fisheries and Wildlife 

 University of Washington 

 Seattle, WA 98195 

 Present address: 



Department of Fisheries and Wildlife 

 Oregon State University 

 Corvallis, OR 98331 



Richard A. Macintosh 



National Marine Fisheries Service, NOAA 

 P.O. Box 1638 

 Kodiak, AK 99615 



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