GROWTH OF THE ADULT MALE KING CRAB 



61 



Years after entry 



Figure 5. — Progressions of the mean values of size groups A, B, and C. x denotes the progression of the mean of the 



size group means. 



of tliese means which shows a rehitively constant 

 increase of approximately 15 mm. per year. 



Although modes other than those discussed were 

 evident, only the more prominent ones in tlie 

 smaller sizes were considered. This selection was 

 guided by the suspicion that due to the lesser fre- 

 quency of molting in the larger sizes, an overlap- 

 ping of year classes occurred, and the modes or 

 means of individual classes became unidentifiable. 

 To alleviate the problem of attempting to define 

 annual growth in the large adult male king crabs 

 by following the progressions of distinctively 

 weak or dominant modes, another metliod was de- 

 veloped, which involves the determination of 

 growth in length per molt and the proportions 

 molting. 



GROWTH INCREMENT PER MOLT 



Three hundred and ten tagged and recaptured 

 crabs representing growth from one molt (ap- 

 pendix table 3) range in size from 98 to 169 mm. 

 before molting. The carapace length at release 



and the observed growth increments for these 

 crabs are shown in figure 6. 



The straight line shown in figure 6, fitted by the 

 method of least squares, represents the regression 

 of growth increment on size for the size range of 

 our data. It is recognized that a second degree 

 polynomial (!'= -62.989-1- 1.1410.Y-0.0041X ") 

 better fits the data, significantly reducing the 

 mean square from 8.99-1 to 8.233. However, growth 

 curves based on linear and curvilinear regressions 

 were compared and it was found that the maxi- 

 mum dift'erence at any one point between the 

 curves did not exceed 2 mm. Since the use of a 

 straight line regression simjjlifies subsequent dis- 

 cussions, and results are not appreciablj- ati'ected, 

 we have considered the growth increment for one 

 molt as being represented bj- the straight line re- 

 gression in figiue (). This line is expressed bj' 

 the equation r=13.14-f-0.018Z. The mean ex- 

 pected growth increment, }', varies from 15.1 nun. 

 for a carapace length of lit) mm. to 16.0 mm. for 

 carapace length 160 mm., a ditference of only 0.9 

 nmi. Thus the growth increment of crabs of these 



