Figure 2. — Temporal distributions of mean lobster larvae pooled 

 density (stations) b> molt stage collected in neuston lows, and mean 

 water temperatures in western Cape Cod Ba>, 1975-77. 



I 



Average density per tow for combined molt stages over the 

 study for all stations was 2.05 larvae/ 1,000 m 3 (Table 2). 



Percent composition of total larval catch for 1975 was: siage 

 I - 59.9°/o, stage 11 - 23.7%, stage 111 - 8.1%, and stage IV - 

 8.3%. Catches at stations 3 and 13 were dominated by first 

 stage larvae which composed 66% and 82°7o, respectively, of 

 station totals. 



At shoal water stations A-D (Fig. 1), we sampled on five 

 dates but collected only eight larvae in 20 tows. Seven larvae 

 were fourth stage, six of which were captured on 25 July. 



1976 Sampling 



The largest number of lobster larvae was collected in 1976, 

 when we captured 871 larvae (Table 2). Hatching began in 

 June and terminated in August (Fig. 2). Only one larva (stage 

 II) was collected in the First week of June when water tempera- 

 tures measured 13.7 °C at the surface and 9.5 °C on the bottom 

 (Fig. 2). Ninety-two percent (801) of the total larval catch 



was taken from 14 July to 3 August at surface water tempera- 

 tures ranging from 9.5° to 16.5 °C. Catch distribution was 

 bimodal with peak densities occurring on 14 July and 3 

 August. By 11 August, with one exception, collections con- 

 sisted exclusively of stage IV larvae. Percent composition of 

 the season's total catch (pooled stations' data) by develop- 

 mental stage was: stage I - 25.5%, II - 19.7°7o, III - 29.6%, and 

 IV - 25.2% (Table 2). Catch at all stations contained relatively 

 large numbers of late stage larvae. Mean density per tow was 

 4.44 larvae/ 1, 000 m\ 



Stations 5 and 6 ranked first and second, respectively, in 

 total number of larval lobsters collected (Fig. 3). The com- 

 bined catch of these stations was 451 larvae, or 52% of the 

 total catch for 1976, consisting of 22.2% stage I, 23.2% stage 

 II, 35.3% stage III, and 19.3% stage IV larvae. Station 1 

 ranked third in total catch (176 larvae), of which 23% were 

 stage IV. Thirty percent (31 larvae) of all first stage larvae 

 (105) were captured at station 1. Fifty first stage larvae, which 

 constituted 48% of the total stage I individuals collected, were 

 caught at stations 5 and 6 combined. 



50 



