FISHERY BULLETIN: VOL. 71, NO. 1 



Females 



Size-frequency polygons of the three ovarian 

 stages of development indicated that immature 

 ovaries occurred in females from 51- to 89-mm 

 carapace length; developing ovaries in females 

 from 69- to 94-mm carapace length; and mature 

 ovaries in females from 77- to 100-mm carapace 

 length (Figure 7). Although the size ranges 

 of the various ovarian stages overlapped con- 

 siderably, the following trends are apparent: 1) 

 immature ovaries predominated in females with 

 carapace lengths less than 75 mm; 2) developing 

 ovaries were most common at intermediate sizes 

 (75- to 90-mm carapace length) ; and 3) mature 

 ovaries gradually increased in frequency at sizes 

 greater than 85-mm carapace length. Unfortu- 

 nately, owing to difficulty in procuring legal- 

 sized lobsters, the sample size of individuals be- 

 tween 85 and 100 mm in carapace length was 

 limited to 47 lobsters; thus the task of deter- 

 mining size where approximately half the female 

 lobsters became mature was confounded. How- 

 ever, the data indicated that a few females ma- 

 tured between 80- and 90-mm carapace length, 

 but the onset of maturity for most females was 

 at carapace lengths greater than 90 mm. This 

 conclusion is further substantiated and expand- 

 ed by the following facets of the maturity inves- 

 tigation. 



100- 

 80- 

 60- 

 40- 

 20- 



100- 

 80 

 60- 

 40 

 20 

 



100- 

 SO- 

 SO- 



40H 



20 







MATURE 

 N = I8 



i - SPERMATOPHORES 



A/' 



DEVELOPING 

 N=87 



My\ti 



.IMMATURE. 

 N=53 



N 



^"A.y 



• • » 



/w 



50 



60 



70 5 80 5 



CARAPACE LENGTH, MM 



90 



100 



Figure 7. — Percentage frequency of the three ovarian 

 stages of development and the occurrence of spermato- 

 phores (triangles) in the seminal receptacles. 



n SPERM PRESENT 

 □ SPERM ABSENT 



60 



70 ' 60 

 CARAPACE LENGTH, MM 



90 



Figure 8. — Number of female lobsters with spermato- 

 phores in their seminal receptacles. 



Spermatophores, the presence of which was 

 another criterion for maturity, were detected 

 more frequently in the seminal receptacles of 

 mature females, particularly those females 

 larger than 90 mm carapace length (Figures 7 

 and 8). Only 2 females with carapace lengths 

 less than 75 mm had sperm cells, whereas 7 of 18 

 (39%) lobsters larger than 89-mm carapace 

 length had spermatophores. From mating ex- 

 periments, Templeman (1932, 1934) concluded 

 that females had to be soft-shelled for mating 

 to be accomplished successfully. Thus, females 

 without spermatophores, even though their ova- 

 ries were classified as mature or well developed, 

 would not be capable of spawning until they had 

 undergone at least another molt and then, while 

 soft-shelled, had copulated with a male. The 

 absence of spermatophores in many females, 

 which were observed to have developing or ma- 

 ture ovaries, suggested that these lobsters would 

 not spawn until they advanced to the next molt 

 class. Thus only 5 of 84 (690 females from 

 80- to 90-mm carapace length were considered 

 to be fully mature (possessed mature ovaries 

 along with spermatophores), whereas the re- 

 maining 79 lobsters would not spawn until they 

 attained carapace lengths of about 91 to 102 mm 

 (assuming a 14% growth increment). 



Templeman (1944) related the onset of sex- 

 ual maturity of Canadian female lobsters with 

 the relative increase in width of the second ab- 

 dominal segment to total lengt-h. This morpho- 



170 



