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Figure 2.— Numbers of lobsler larvae caught per 1,000 m 1 of waler filtered and 

 average waler temperature for each sampling dale in Buzzards Bay neuston sam- 

 pling, 1976-79. Surface temperature (solid line); bottom temperature (broken 

 line); vertical arrows indicate starting and ending dates for sampling in each year. 



early August, encompassing a period of about 11 or 12 vvk. 

 Generally there was a small peak in abundance of stage I 

 larvae in late May and well before the seasonal peak in mid- 

 June (Fig. 3); this has been noted previously by Collings et 

 al. J in the northeastern part of Buzzards Bay. 



In 1976 the pattern of larval abundance by stage (Fig. 3) 

 showed early stage larvae to be more abundant than later 

 stages. In 1977 and, especially, in 1978 later stages were as 

 abundant or more so than earlier stages. In 1979 the very 

 high numbers of all stages caught on 18 June greatly altered 

 the pattern of abundance for that year. 



In order to examine day-night differences in the larval 

 catch, we made three daylight and three night tows on the 

 evening of 9 June 1976 at stations B, C, and D (Fig. 1). Only 

 the first three larval stages were caught (Fig. 4). Station B, 

 1820-1850 h EST, yielded 257 larvae, the largest catch of the 

 1976 season. At station C, 1855-1925 h, 113 larvae were 

 caught, and at station D, 1930-2000 h, 31 larvae were taken. 

 These were the three daylight tows, although the light was 

 fading through the last two of these. Sunset occurred at 1921 

 h. For the night tows the times and catches were: station D, 

 2025-2055 h, 45 larvae; station C, 2100-2130 h, 28 larvae; and 

 station B, 2135-2205 h, 17 larvae. Catch dropped rapidly as 

 the light level decreased. Further, the catch composition by 

 stage changed greatly, with stage I larvae dominating during 

 daylight and stage III larvae making up much of the catch 

 after dark. 



DISCUSSION 



The results from this study and from those of Collings et al. 

 (footnote 3), indicate that the numbers of lobster larvae caught 

 in Buzzards Bay considerably exceed those caught in other 

 New England areas, such as the Maine coast (Sherman and 

 Lewis 1967), Cape Cod Bay (Anderson and Scotton 4 ), Vine- 

 yard Sound (Herrick 1896), Block Island Sound (Bibb and 

 Hersey 5 ), and Long Island Sound (Lund and Steward 1970). 

 Indeed, it appears, when Canadian studies are considered as 

 well, that the larvae are at least as numerous here as in any 

 other location. 



The abundance of early stage larvae in an area depends in 

 part on the numbers of ovigerous lobsters present. Collings et 

 al. (footnote 3) indicated that Buzzards Bay lobsters matured 

 at a smaller size than those in Cape Cod Bay, presumably due 

 to higher water temperatures in the former area. This is consis- 

 tent with the results of Templeman (1936) who found indica- 

 tions that lobsters matured at smaller sizes in the warmer 

 water areas off Canada than in colder areas. Lobster fisher- 

 men also have reported a higher proportion of sublegal 



'Collings, W. S., C. C. Sheehan, S. C. Hughes, and J. L. Buckley. 1980. 

 Biological investigations relative to the effects of a second electrical generating 

 unit upon some of the marine resources of northern Buzzards Bay and the 

 Cape Cod Canal. Unnumbered report. 423 p., append. Canal Electric Co., 

 Sandwich, MA 02563. 



'Anderson, R. D., and L. N. Scotton. 1978. Marine ecology studies related 

 to operation of Pilgrim Station. Final Rept. July 1969-Dec. 1977, Vol. 1, 407 p.. 

 Vol. 2, 217 p. Boston Edison Co., 800 Boylston St., Boston, MA 02199. 



Bibb, B. C, and R. Hersey. 1979. Distribution and abundance of iobster 

 larvae in Block Island Sound, 1978. 1978 Final Rept., Raytheon Environ, and 

 Oceanogr. Serv., 89 p. New England Power Co., 20 Turnpike Rd., Westboro, 

 MA 01581. 



31 



