KROUSE: INCIDENCE OF CULL LOBSTERS IN CATCHES 



Table 3. -Percentage of lobster culls with missing claws by 5-mm size 

 groups for research catches of wire and wooden traps. 



Wire traps 



Wood traps 



Number of lobsters .,. . 



Carapace Missing 



length Regenerat- Missing claw 



(mm) ing claw claw (%) 



Number of lobsters 



Regenerat- 

 ing claw 



Missing 

 claw 



Missing 

 claw 

 {%) 



catches (Table 2) but also by the commercial 

 catches for 1968-74 (Table 4). For both catches, 

 more legal-sized culls occurred in the 81- to 85-mm 

 size group while the percentage of culls gradually 

 decreased for carapace lengths >85 mm. If, once 

 again, it is assumed that fishing operations often 

 cause culled lobsters and knowing that legal 

 lobsters are handled only once and not repeatedly 

 as may be the case for sublegal-sized lobsters, one 

 would expect fewer culls amongst legal lobsters 

 along with a gradual reduction in culls for sizes >85 

 mm. Since this study's data demonstrate this very 

 pattern, my contention concerning the possible 

 injurious effects of fishing activities on lobsters 

 <81 mm is strengthened. Certainly there is a 

 greater likelihood of a lobster becoming injured 

 when as a result of fishing operations this lobster 

 is: 1) crowded with other cannibalistic lobsters in a 

 trap; 2) held captive in a trap which may undergo 

 rigorous movement during a storm; 3) hauled 

 boatside with appendages dangling between the 

 trap's laths; and 4) removed from the trap while 

 clinging to the trap, fishermen, or another lobster 

 and eventually released for a descent to the ocean 

 floor during which predation may occur. 



Table 4.-Incidence of lobsters with missing claws by 5-mm size 

 groups occurring in the commercial catch along the Maine coast 

 (1968-74). 



Effect of Fishing Intensity on 

 Cull Frequency 



The relationship of fishing intensity and its 

 influence on cull incidence was investigated by 

 calculating the frequencies of culls caught with 

 wire and wood lobster traps (Table 5) at three 

 different fishing sites near Boothbay Harbor 

 (Figure 1). In addition, length-frequency histo- 

 grams were constructed by 1-mm increments of 

 the catches for each of the sampling sites (Figure 

 2). This analysis revealed that catches off Capitol 

 Island, the most intensively fished area, contained 

 more culls (23.3% for wire and 22.0% for wood 

 traps) than either the catch of Damariscove 

 (21.2%) or Squirrel islands (12.7% for wire and 

 17.9% for wood traps) which had the fewest culls. 

 Although Damariscove and Squirrel islands ap- 

 peared to have similar trap concentrations based 

 on visual sightings of pot buoys, appreciably more 

 culls were trapped at Damariscove. Possible rea- 

 sons for this difference may be related to: 1) 

 lobsters being maimed by excessive movement of 

 traps over the substrate during storms off the 

 more exposed seaward shoreline of Damariscove 

 (waters fished at Squirrel were more sheltered); 2) 

 Damariscove's greater abundance of small lob- 

 sters which are more vulnerable to injury [average 

 size of lobsters in Damariscove catch was smaller 

 than those of the other two areas (Figure 2), and 

 the percentage of lobsters with missing claws was 

 highest at Damariscove (Table 5)]; and 3) perhaps, 

 an error in our rather subjective determination of 

 nearly equal fishing intensities for both islands. 

 Nevertheless, there does appear to be a positive 



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