FISHERY BULLETIN: VOL. 73, NO. 4 



simultaneously with the same spatial and tem- 

 poral arrangements. 



Body Proportions of Lobsters 



To circumvent the spatial and temporal 

 problems between commercial (boat trips) and 

 research gear to a certain extent, we took body 

 measurements of 217 lobsters, specifically 

 carapace length, width, and height for sizes 

 between 70 and 90 mm carapace length. These 

 measurements should enable us to reach a more 

 objective determination concerning the retention 

 and escapement potential of various sized lobsters 

 through different lath spacings. 



RESULTS AND DISCUSSION 

 Samples from Commercial Gear 



For the 21 boat trips with commercial fishermen, 

 we counted their entire catch of 12,071 lobsters of 

 which there were 2,311 legal lobsters (Table 1). 

 This catch resulted from 4,026 trap hauls for a 

 catch of 0.57 legal lobsters per trap haul or 0.22 

 legal lobsters per THSOD. 



There are omissions in some of the data 

 categories per boat trip because the sampling 

 procedure evolved from successive trips aboard 

 vessels; thus samplers learned by experience and 

 observation what could or could not be ac- 

 complished under different physical conditions in 

 each vessel. Nevertheless, subtotals can be 

 gleaned from the boat trips with the more 

 complete information. For example, there were 

 156 berried and/or "V"-notched females from 18 

 of the 21 boat trips. Even though this is a subtotal, 

 it is an alarmingly low number. Of course, such 

 things as season of year, area fished, and 

 availability of berried females could affect this 

 number. Still, we continue to be concerned about 

 the possibility of a precarious limit of an adequate 

 spawning stock (Thomas 1973; Krouse 1973). 



The percent females is another estimate related 

 to the reproduction potential of the exploited 

 population of lobsters. For those lobsters that we 

 measured and determined sex, 52.9% were females 

 (sublegal and legal). This estimate is close to the 

 49.0 to 53.8% females that we estimated by year 

 (1966-73) from the survey of the commercial (legal 

 lobsters) and natural (mostly sublegal) population 

 of lobsters. 



These estimates are in conflict with the expec- 



tation that there should be more males than 

 females in the commercial catch because berried 

 and/or V-notched females must be returned to the 

 ocean by law. Again, this situation points to a low 

 number of sexually mature females. 



To reach definite conclusions concerning the 

 stock-progeny-recruitment relationships, we 

 should follow the procedures of Beverton and Holt 

 (1957) and Ricker (1958). This will be possible with 

 continued support of this program and continued 

 surveys on the commercial and natural popula- 

 tions of lobsters. 



Length Frequencies 



We measured the carapace length of 3,595 lob- 

 sters; the sex ratio (male:female) was 1:1.2. A his- 

 togram of these length frequencies (Figure 2) 

 portrays the same situation that we have demon- 

 strated from the commercial and natural surveys. 

 That is, there are relatively large numbers of lob- 

 sters (2,937 or 81.7%) under the legal minimum 

 size, while there are considerably fewer lobsters 

 (658 or 18.3%) at and above the legal minimum size 

 of 81 mm (3'^/ 16 inches) carapace length. In fact, 

 94.0% of the legal catch is constrained within a 

 Va-inch size range immediately above the legal 

 minimum size. These conditions confirm the high 

 exploitation rate of 0.86 that can be calculated 

 from Thomas (1973). 



Considering the modal lath spacings of traps 

 used in each boat trip, there is a marked difference 

 in the number of sublegal- and legal-sized lobsters. 



N.3595 



CARAPACE LENGTH (MM) 



Figure 2. -Length-frequency distributions of lobsters caught in 

 traps several lath spacings) used by commercial fishermen 

 (1971-73). 



864 



