Trott (1956) have quite convincingly demon- 

 strated that the catch in numbers or pounds 

 per trap is not a valid index of stock density. 

 Therefore, when this survey started, we knew 

 that we would have to determine a different 

 effort value than had been considered pre- 

 viously. 



Initially we hoped that the catch in numbers 

 per trap-haul would satisfy the need to find, 

 at least, an indicator of stock density. We col- 

 lected this type of information from August 

 1966 through August 1967. Upon analysis of 

 these data, we found that while this catch-per- 

 unit-of-effort value does approximate the con- 

 dition in the fishery at least for May through 

 July, it is not adequate for most other months. 

 Evidently there are other factors influencing 

 even this catch-per-unit-of-effort value. Also, 

 these unknowns are apparently constant for 

 May through July and quite variable in other 

 months. A factor that could account for these 

 situations is the number of set-over-days in 

 association with availability. 



In addition to the established interview ques- 

 tions, we added one more regarding the number 

 of set-over-days for the group of traps hauled 

 per boat. This additional information began 

 in September 1967. A preliminary analysis, as 

 the data were collected, looked promising. Then, 

 with a monthly and yearly backlog of survey 

 data for 1968 through 1970, we determined 

 the following specific relationships for each 

 of these years : 



(1) The catch in numbers per trap-haul as 

 it is related to surface water temperature; 



(2) The catch in numbers per trap-haul-set- 

 over-day as it is related to surface water 

 temperatures; 



(3) The catch in numbers per trap-haul-set- 

 over-day as it is related to the number of 

 boat-days. 



In 1968, these relationships segregated them- 

 selves into three distinct periods during the 

 calendar year: 



Period 1: Covers those months when avail- 

 (January- ability could be a major factor; 

 April) i.e., water temperature in as- 



sociation with metabolic rates, 

 leading to vulnerability in a trap 



fishery; also considering acces- 

 sibility (moving from deeper to 

 shallower water). 

 Period 2: Includes those months when ef- 

 ( May -July) fort and the assumed molt- or 

 year-class strength from the 

 preceding year could be a major 

 determinant. 

 Period 3: Encompasses those months 

 (September- when recruitment through molt- 

 December) ing with increased vulnerability 

 during the current year in as- 

 sociation with the defined effort 

 could have the greater effects. 

 We hypothesize that after sev- 

 eral days, new shell lobsters 

 actively seek food thereby in- 

 creasing their vulnerability to 

 the baited trap (personal ob- 

 servations from laboratory stu- 

 dies). 



Ideally, in all of these periods and relation- 

 ships we should use the bottom ocean tempera- 

 tures either by area or coastwide. Again, limited 

 manpower and money made this an impossi- 

 bility. As a result, we used the surface tempera- 

 tures that we collected at the dealer locations 

 during the survey (Fig. 8). 



In considering the catch in numbers per trap- 

 haul with surface water temperature (Fig. 9), 

 we deduced the following: 



Period 1 : As the mean surface water tem- 

 (January- perature increases by month, 

 April) the catch in numbers per trap- 



haul generally decreases. This 

 situation conflicts with the pre- 

 mise that availability should be 

 increasing with the warming 

 ocean waters. 

 Period 2: The downward convex curve 

 (May-July) possibly indicates that even 

 though the monthly mean ocean 

 temperature is increasing, the 

 age- or molt-class strength is 

 reduced prior to recruitment. 

 However, the convex reduction 

 might indicate that availability 

 is still a factor rather than age- 

 or molt-class strength from the 

 preceding year. 



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