FISHERY BULLETIN: VOL. 78, NO. 2 



ton and subsurface water column collections from 

 shelf waters in the Middle Atlantic Bight. My ob- 

 jectives specifically were to: 1) determine whether 

 a reservoir of Callinectes larvae, particularly 

 megalopae, exists in shelf waters; 2) determine 

 abundance relationships between Callinectes lar- 

 vae in neuston and water column samples; 3) 

 examine the role of certain environmental factors 

 (e.g., temperature, salinity, location) in the dis- 

 tribution and abundance of these larvae; 4) assess 

 the role of Callinectes megalopae in larval re- 

 cruitment and dispersal in view of my findings and 

 results of laboratory studies of temperature- 

 salinity tolerances of larvae; and 5) examine in- 

 teraction of the developmental migratory se- 

 quence, biogeography, and evolutionary history of 

 Callinectes. 



METHODS 



Zooplankton collections were made as part of a 

 2-yr survey (Table 1) conducted by the Virginia 

 Institute of Marine Science (VIMS) for the Bureau 

 of Land Management (1975-77). This study was 

 designed to provide ecological information prior to 

 drilling for oil on the Middle Atlantic Bight conti- 

 nental shelf. In addition to zooplankton studies 

 the survey included studies of benthic and epiben- 

 thic communities and the physical, chemical, and 

 geographical oceanography of the shelf and over- 

 lying waters. 



During the first year, six stations were occupied 

 seasonally (quarterly) on a transect across the 

 shelf off Atlantic City, N.J. (Figure 1; Table 2: CI, 

 Dl, N3, E3, F2, Jl). Zooplankton in the water 

 column was sampled at night by paired, double 

 oblique tows with 60 cm diameter, opening-closing 

 bongo nets (McGowan and Brown^) (505 fim and 

 202 ixm mesh). Bongo nets were metered (General 

 Oceanics, Inc. flowmeters^) and were closed during 

 passage through the surface layer. Neuston was 

 sampled every 3 h over a 24-h period with a neus- 

 ton net designed at Woods Hole Oceanographic 

 Institution. This sampler consisted of two 

 hydrodynamically-shaped, foam-filled floats con- 

 nected by an endless fiber glass band (Grant'). The 



Table l. — Dates for cruises in the Middle Atlantic Bight, 1975- 

 77, over which Callinectes larvae were sampled. 



*McGowan, J. A., and D. M. Brown. 1966. A new opening- 

 closing paired zooplankton net. Univ. Calif., Scripps Inst. 

 Oceanogr. Ref. 66-23, 56 p. 



^Reference to trade names dpes not imply endorsement by the 

 National Marine Fisheries Service, NOAA. 



'Grant, G. C. 1979. Middle Atlantic Bight zoo- 

 plankton. Spec. Rep. Appl. Mar. Sci. Ocean Eng., Va. Inst. Mar. 

 Sci. 192, 236 p. 



252 



'Cruise split into two legs. 



Figure l. — Study area and sampling stations for surface and 

 subsurface zooplankton in the Middle Atlantic Bight, 1975-77. 

 Stations LI, L2, L4, L6, B5, A2 were sampled only during the 

 second year of the study; CI, Dl, N3, E3, F2, Jl were sampled 

 both years. 



mouth of the net was 1.0 m wide, and in calm water 

 the gear sampled approximately the upper 12 cm 

 of the water column. However, the net appeared to 

 sample, on the average, less than the upper 12 cm 

 due to sea conditions and towing characteristics of 

 the ship and sampler. Calculated volumes were 

 based on a 12 cm sample depth and were thus 

 overestimated, resulting in underestimation of 



