FISHERY BULLETIN: VOL. 74, NO. 4 



Table L-Monthly incidence of lobster culls in research catches 

 near Boothbay Harbor, Maine, 1969-74. 



69''40' 



69035 



Figure l.-Map showing the areas fished near Boothbay Harbor, 



Maine. 



in the catch during winter-spring (26.9-31.3%), 

 then subsided in July-August (18.1-19.4%), and 

 increased in the fall (17.7-25.6%— variations in fall 

 percentages may be due to sporadic shedding 

 during this season). These seasonal changes might 

 be related to the time of molting (July-September) 

 associated with temporal fluctuations in fishing 

 pressure. If we assume that a high percentage of 

 the total number of culls are caused by fishing 

 operations as suggested by earlier observations of 

 fishermen's needless handling of excessive 

 numbers of sublegal size lobsters (Krouse and 

 Thomas 1975), then the decline in cull frequency 

 during July and August (peak of shedding) may be 

 explained, in part, by: 1) some culls losing this 

 status after shedding and regenerating normal 

 size claws, and 2) small lobsters (usually nonculls 

 by virtue of their nonvulnerability to fishing gear) 

 being recruited into the fishery at this time as a 

 result of shedding. Even though the catch data of 

 this study reveals that a high percentage of 

 lobsters <45 mm carapace length were culls, most 

 of these smaller culls probably acquired this con- 

 dition while confined in our lobster traps. 



Table 2.— Percentage of lobster culls by 5-mm size groups in 

 research catches near Boothbay Harbor, Maine, 1969-74. 



Carapace 

 length 

 (mm) 



Total 

 number 

 caught 



Culls 

 (%) 



Carapace 

 length 

 (mm) 



Total 

 number 

 caught 



Culls 



{%) 



The frequency of culls by 5-mm increments 

 (Table 2) indicated that culls are most prevalent at 

 carapace lengths ^45 mm and progressively less 

 numerous at lengths ^86 mm. The high incidence 

 of culls for small lobsters can be attributed, at 

 least in part, to these lobsters being particularly 

 defenseless to claw loss inflicted by larger lobsters 

 wnthin the trap. On several occasions we have 

 either caught small lobsters with recent claw 

 losses in traps containing larger lobsters or ac- 

 tually witnessed larger lobsters destroying the 

 claw of their diminutive opponent. To further 

 substantiate this explanation of the two cull 

 categories, i.e., regenerating and missing claws, 

 the missing claw group predominated for lobsters 

 ^50 mm; however, for sizes ^51 mm, lobsters with 

 regenerating claws usually outnumbered those 

 without claws (Table 3). This disparity was more 

 pronounced for wood traps within the 81- to 85- 

 and 86- to 90-mm groupings. Considering that 

 legal-sized lobsters are handled only once and 

 therefore are probably less prone to claw loss, then 

 one would expect these larger lobsters to have a 

 higher incidence of regenerating claws. Con- 

 versely, those sublegal-sized lobsters between 76 

 and 80 mm that are repeatedly discarded from the 

 fishermen's catch have a preponderance of missing 

 claws for catches with wire and wood traps. 



The decline in the incidence of culls at the legal 

 sizes (Maine minimum legal size is 81 mm carapace 

 length) is manifested not only by the research 



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