780 



Fishery Bulletin 90(4). 1992 



0.7 



0.6 



0.5 



0.4 



# Herendeen Red King Crab 



■ Pnbilof Red King Crab 



O Herendeen Blue King Crab 



D Pribilof Blue King Crab 



A Herendeen Blue King Crab 7 + 7 



D 55 



Ol5 



A 14 



46 



162 

 22 



• 56 

 18 



Stage 



Figure 5 



Paralithodes spp. rostrum length/cara- 

 pace length by stage. Values are mean 

 ratios ( ± 1 SD); numbers are the number 

 of zoeae measured for each value. 



eyes for Herendeen Bay BKC, suggesting that eye 

 length is not rehable for distinguishing the two species. 

 No intraspecific differences between areas were de- 

 tected for either rostrum/carapace length or eye length 

 for RKC. 



The mean eye length of RKC larvae was significant- 

 ly less (p<0.05) at each stage than the means of all 

 groupings of BKC. In addition, the mean of the 7 + 7 

 zoeae-I BKC was significantly less than those with 8 + 8 

 (Fig. 6). BKC larvae from Herendeen Bay showed 

 great variation in number of telson spines. Only 45.9% 

 of all BKC larvae had a spine count of 8 + 8, the major- 

 ity having some other combination of 7, 8, or 9 spines 

 on each side of the telson. In contrast, the majority of 

 BKC zoeae from the Pribilof Islands (84%) had a spine 

 count of 8 + 8 (Fig. 7). RKC larvae showed little varia- 

 tion in telson spines, with only 0.9% of the zoeae from 

 Herendeen Bay and 3.2% from the Pribilof Islands 

 deviating from the count of 7 + 7. 



Discussion 



BKC zoeae are generally distinguished from RKC 

 zoeae by the presence of an additional pair of inner 

 spines on the telson (Fig. 8A,B), and for king crab 

 zoeae collected near the Pribilof Islands this was a 

 reliable character for separating the two species. Only 

 3.2% of the RKC zoeae collected from this area 

 deviated from the 7 + 7 pattern. Even though 16% of 

 the BKC zoeae differed from 8 + 8, this difference was 

 almost invariably in the form of an extra 1 or 2 inner 

 spines, making confusion with RKC unlikely. BKC 

 zoeae were visibly much larger as confirmed by their 

 greater carapace length, and had shorter rostrums and 

 larger eyes. 



A substantially different pattern was apparent in 

 samples from Herendeen Bay, where 42% of zoeae-I 

 BKC were missing one spine from the telson (Fig. 8C) 

 and an additional 18% missing two spines (Fig. 8D). 

 Because the missing spines are the innermost of the 

 two pairs, those remaining tend to be considerably 

 longer than the single pair in RKC; yet as Figure 8D 



Figure 6 



Mean eye length ( ± 1 SD), and number of 

 Paralithodes spp. zoeae measured. 



