54 



FISHERY BULLETIN OF THE FISH AND WILDLIFE SERVICE 



250 



£ 200 



« 



E 

 c 



u 



o 



o 



o 



150 



100 



10 12 14 16 18 

 Age in years 



20 22 24 26 28 30 32 



Figure 1. — King crab growth curves from published results. Curves Wi and W- derived from Wang ( 1937 ) for crabs 

 from Northern Hokkaido and Sakhalin, respectively; curve N derived from Nakazawa (1912) ; and curve M from 

 Manikawa (1933). 



frequency distributions. Nakazawa (1912) esti- 

 mated growth of king crabs by combining data 

 from his studies on king crab with publislied in- 

 formation on the frequency of molt and gi-owth 

 rate of Homarus a.mericamis and Cancer pagurus. 

 The growth curves described by the above investi- 

 gators are presented in figure 1.^ 



AVide differences in growth rates are indicated, 

 and though the difference may in part be due to 

 geographic separation, it appears that there maj^ 

 be some errors in interpretation. 



Wang (1937), grapliically presents a size- 

 frequency distribution which shows a mode at 45 

 mm., a second at 85 mm., and others centered at 

 115 mm., 135 mm., and 155 nmi. From other size- 

 frequency distribution data collected in 3 suc- 

 cessive years, he observes weak and dominaHt 

 groups progressing from 135 mm. to 160 or 165 mm. 



1 Marukawa, Nakazawa, and Wang's results were presented in 

 terms of carapace width, and are so shown in figure 1. However, 

 most if not all king crab investigators are presentlj' using cara- 

 pace length measurements, since tiiis dimension is more definite 

 and the points of measurement are more resistant to flexing 

 when measuring calipers are applied. The conversion from width 

 to length for male king crabs may be made by the formula : cara- 

 pace length = .144-0.92.5 (carapace width), for sizes less than 95 

 mm. in carapace width ; and for sizes greater than 95 mm. the 

 formula is: carapace length = l.S4 + 0. 744 (carapace width). 

 These relations were calculated from length-width measurements 

 of eastern Bering Sea king crabs. 



and then to 185 mm. Wang combines the two sets 

 of data and interprets the first two modes in the 

 size-frequency distribution to be indicative of sizes 

 at ages 1 and 2, and then from the modal progres- 

 sion, the sizes at ages 3, 4, and 5, to be 135 mm., 

 165 mm., and 185 mm., resi>ectively. Wang appar- 

 ently does not interpret the increased frequency 

 of 115-mm. crabs as representing a year class. Un- 

 fortunately, sufficient data are not presented to 

 permit examination of his frequency distribution, 

 and reasons ^re not given for excluding the 115- 

 mm. group which is quite evident in the size- 

 frequency distribution presented. 



Wang's assignment of age 1 to the first mode in 

 his sample (45 mm.) is not consistent with the 

 findings of other researchers. Marukawa and 

 Nakazawa both describe 1-year-old crabs to be of 

 about 7 and 8 mm., respectively. Also, the Fish- 

 eries Agency of Japan (1958) reports that 3,084 

 juvenile crabs, ranging in size from 6 to 15 mm. in 

 carapace length with a mean sjze of 9 mm. (cara- 

 pace width, 8 mm.), were collected in the eastern 

 Bering Sea in late May and early June of 1957. 

 Since hatching in the eastern Bering Sea occurs 

 in April and May and it is generally agreed that 

 there is about a 10-week period of larval life be- 



