rO 



E 



o 

 o 

 o 



tr 



LU 



a. 



< 



D 



z 



CD 



< 



p7x^ 



31 8 14 21 28 5 14 20 26 2 

 MAY JUNE JULY AUG 



1977 



■# 



_n 



■/,■ 



ii 



P'Mfl CffEBL 



6 14 22 28 5 12 19 25 2 9 16 30 

 JUNE JULY AUG 



1978 



Figure 3. — Stage composition by survey. Mean of all stations, surface and near-bottom, day and night samples. 



Stage I larvae were in the water column for a total of 10 

 wk in 1977 and 8 in 1978 (Fig. 2). In 1977, the maximum 

 abundance of stage I larvae corresponded to maximum total 

 abundance, approximately 3 to 5 wk following the first oc- 

 currence of larvae. During the period, mean daily surface 

 and bottom temperatures at station EB-B ranged from 14.5° 

 to 17.5°C and 14.0° to 16.6°C, respectively. In 1978, peak 

 stage I abundance occurred over a 3-wk period from late June 

 to early July. Mean daily surface and bottom temperatures 

 at EB-B during this period ranged from 14.5° to 15.9°C and 

 12.8° to 14.8 °C, respectively. 



The appearance of later stage larvae in the water column 

 varied annually (Fig. 3). Stage II larvae were typically found 

 1 to 2 wk after the first appearance of stage I larvae. Stage 

 III and IV were first collected 2 to 4 wk later. Stage II and III 

 were first found when the bottom temperature at EB-B was 

 approximately 13°-14°C and stage IV at 14°- 15 °C. 



Estimated larval density in 1977 samples declined with each 

 successive stage. In 1978, stage IV larvae, however, were 

 extremely abundant and were observed over a longer time 

 period than in 1977. Stage IV larvae composed 52% of the 

 season total in 1978, but only 4% of the 1977 total (Table 1). 



Table 1. — Mean abundance (numbers per 1,000 m' ± 95% confi- 

 dence limits) and percent composition by stage of lobster larvae 

 collected off East Beach, Block Island Sound. 







1977 





: 1978 











Percent 





Percent 



Stage 



Abundance 





of total 



Abundance 



of total 



I 



1.33±0.54 





59 



0.26±0.13 



23 



II 



0.53 ±0.26 





24 



0.16 + 0.10 



14 



III 



0.30±0.14 





13 



0.12±0.07 



11 



IV 



0.10 ±0.06 





4 



0.59±0.38 



52 



Total 



2.26±0.83 





100 



1 . 1 3 ± 0.48 



100 



1 107 sampling events 31 May - 2 August 1977). 

 : 1 32 sampling events ( 1 5 June - 30 August 1978). 



Vertical and Diel Distribution 



Four-way ANOVA indicated that mean surface density was 

 significantly higher than near-bottom density at stations EB-B 

 and EB-C in both 1977 and 1978 (Table 2). Relatively high 



17 



