TABLE 1. Catch statistics for lobsters caught in pots from May through October (1978-87). 



discontinue impingement monitoring at Unit 2 

 (NUSCO 1988). 



Lobster larvae were sampled from 1984 to 1987 

 during their period of occurrence (May through 

 July) at Units 1 and 2 discharges. Sampling was 

 not conducted at Unit 3 because of design prob- 

 lems with the gantry system used to collect sam- 

 ples at the Unit 3 outfall. Cooling water flows 

 for combined 3-unit operation were used for cal- 

 culating total entrainment estimates for the larval 

 season. Samples were collected with a 1.0 x 6.0 

 m conical plankton net of 1 .0 mm mesh. Sample 

 volumes were averaged from those calculated from 

 four General Oceanic flowmeters; about 4000 m 

 of cooling water was filtered in each sample by 

 deploying the net for 45-60 minutes. Four day 

 and four night samples were collected weekly (1 

 day, 1 night on each of 4 days). Each sample 

 was placed in a large 1.0 mm mesh sieve and kept 

 in tanks supplied with a continuous flow of sea- 

 water. Samples were sorted shortly after collection 

 in a white enamel pan and larvae were examined 

 for movement and classified as either live or dead. 

 Lobster larvae were also classified by stage ac- 

 cording to the criteria established by Ilerrick 

 (1911). 



Results and Discussion 



Abundance and Catch Per Unit Effort 



The total numbers of lobster caught during 1986 

 and 1987 were 7,211 and 7,280, respectively, and 

 both were within the range of values reported 

 since 1978 (Table 1). Total catch per unit effort 

 values for 1986 (1.70) and 1987 (1.72) were also 

 within the range of wire pot values (0.85-2.10). 

 The lower number cauglit and smaller total CPUE 

 from 1978-81 was due to the use of wood pots 

 (NUSCO 1987a). In wood pots, lobsters were 

 more vulnerable to capture at sizes greater than 

 76 mm and in wire pots at sizes greater than 70 

 mm (Keser et al. 1983). The performance of 

 wood and wire pots was evaluated (NUSCO 

 1987a) and provided the basis for using wire pots 

 exclusively in our studies. 



Figure 2 presents geometric mean CPUE for all 

 sizes and legal-sized lobsters caught from 1978 to 

 1987. The total catch mean CPUE for 1986 and 

 1987 (1.585, 1.633) was within the range of values 

 reported from 1978 to 1985 (0.904-2.006). No 

 significant trends were identified for total CPUE 

 (test for significance of slopes; r=0.25, p=0.48). 



Lobster Population Dynamics 



123 



