Distribution and Abundance of Larval Lobsters 



(Homarus americanus) in Buzzards Bay, 



Massachusetts, During 1976-79 



FRED E. LUX, GEORGE F. KELLY, and CHARLES L. WHEELER' 



ABSTRACT 



In 280 neuston tows during 1976-79 in Buzzards Bay, Mass., 16,679 larval lobsters (stages 1-IV) were 

 collected. The larvae began to appear in catches in late May in each year, reached peak numbers in mid-June, and 

 disappeared from the plankton by early August. The bottom temperature was approximately I3°C when larvae 

 first were caught and about I7°C at the peak of larval production. The mean number of larvae caught per 1,000 

 m J of water filtered ranged from 9.6 in 1978 to 43.7 in 1979. Largest catches were obtained on 18 June 1979 

 when 6,746 larvae were caught in five 0.5-h tows. The catch of late stage larvae was unusualh high in 1978 when 

 stage IV larvae were twice as numerous as the other stages combined. The sampling results indicated that Buz- 

 zards Ba> is an area of high production of larval lobsters. 



INTRODUCTION 



The National Marine Fisheries Service (NMFS) at Woods 

 Hole began sampling planktonic larval stages of lobsiers 

 (Homarus americanus) in Buzzards Bay, Mass., in May 1976. 

 This effort has continued each year with sampling beginning in 

 early May prior to the hatching of lobster eggs and ending in 

 early August after the larvae have settled out of the plankton. 

 The survey was begun as part of a joint study with the 

 Massachusetts Division of Marine Fisheries of the distribution 

 and abundance of lobster larvae in Cape Cod Bay, the Cape 

 Cod Canal, and Buzzards Bay. We sampled the middle section 

 of Buzzards Bay (Fig. 1). This paper reports the results from 

 this work in 1976-79. A general summary of information on 

 distribution and abundance of lobster larvae has been pre- 

 pared by Fogarty (1983) and therefore is omitted here. 



Buzzards Bay varies in depth from < 5 m at the Cape Cod 

 Canal end to about 30 m at the bay mouth. Sediments con- 

 sist largely of sand and silt, although there are numerous areas 

 of rocky bottom and, along the northwest shore, rock ledge. 



The bay, which lies entirely within Massachusetts territorial 

 waters, is closed by State law to fishing with trawls or nets. 

 There are, however, active commercial and recreational trap 

 fisheries for lobsters from spring to late fall. Lobsters <81 mm 

 carapace length and all ovigerous females must be returned to 

 the water. Precise lobster landings from Buzzards Bay are not 

 known, although catch reports filed to the State by lobster 

 fishermen indicate that an estimated 500 tons may be landed 

 per year (Beals et al. 2 ). 



METHODS 



Numerous reports have demonstrated that planktonic 

 lobster larvae are positively phototactic and are found at or 

 near the water surface during daylight (Fogarty 1983). There- 

 fore a neuston net (1 x 2 m mouth, 9 m length) with a mesh 

 size of 0.97 mm was used for sampling. The net was towed 

 from the end of a boom extending 2.5 m out from the star- 

 board side of a 12 m research vessel. Tows were made in a 

 straight line with the net approximately 20 m astern of the 

 vessel and out of the wake; the net mouth was from one-half to 

 two-thirds submerged. Towing speed in 1976, based on dis- 

 tance covered, was estimated at 4.6-5.6 km/h (2.5-3.0 kn) and 



Northeast Fisheries Center Woods Hole Laboratory, National Marine Fish- 

 eries Service, NOAA. Woods Hole, MA 02543. 



'Beats, R. W., C. J. Kilbride, and G. M. Nash. 1978. 1977 Massachusetts 

 coastal lobster Fishery statistics. Mass. Div. Mar. Fish. Tech. Ser. 13, 19 p. 



Figure 1 .—Sampling stations for neuston lows in Buzzards Bay, Mass., 1976-79. In 

 1976, stations A-D (upper transect) were sampled; in 1977-79. stations 1-6 (lower 

 and upper transects) were sampled. 



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