RICHARDS and KENDALL: DISTRIBUTION OF SAND LANCE LARVAE 



Figure 3. — Distribution and abundance of sand lance 

 larvae in the December cruise in shallow tows. 



Jersey coast in the latitude of Barnegat Inlet, 

 N.J. Off the mouth of Chesapeake Bay, the 

 greatest numbers occurred during the winter. 

 Norcross et al. (1961) reported a similar 

 seasonal peak in capture rate off Chesapeake 

 Bay during 1960. Data from the deep tows were 

 similar, with the greatest abundance off Mon- 

 tauk Point extending southward offshore. An- 

 other group occurred off Delaware Bay, extend- 

 ing in a band to North Carolina (Figure 4). 

 Temperatures in the areas of capture in winter 

 varied from 0° to 6°C and salinities varied 

 from 31 to 33"/oo. Plankton volumes were less 

 than 100 ml/tow from deep offshore water, 

 but approached 200 ml/tow near the mouths 

 of some estuaries. 



During April, sand lances were more widely 

 dispersed and occurred closer to shore from 

 Martha's Vineyard to Assateague Island, Md., 

 than in winter (Figure 5). Similar numbers 

 were taken south to Cape Henry, Va., but 

 further offshore. None occurred farther south. 



except from a small patch near the surface off 

 Cape Hatteras. As before, larvae were most 

 abundant throughout the water column off the 

 southern New England coast. Only offshore 

 of Maryland were larvae in comparable num- 

 bers. Within these same areas, the plankton 

 volumes had increased since winter, providing 

 a good source of food for larvae longer than 

 5 mm (Covin, 1959). Temperatures had warmed 

 slightly from winter, but most larvae were 

 still taken in water of less than 7°C. The 

 few near Chesapeake Bay and Cape Hatteras 

 were taken in warmer water up to 13 °C. Bottom 

 temperature was about 1°C lower than at the 

 surface. Larvae were distributed throughout 

 the salinity range of 31 to 33'7oo found in 

 most of the sampled area but were absent in 

 the less saline water off Delaware and Chesa- 

 peake Bays. Plankton volumes were similar 

 to those offshore in winter, but those between 

 10 and 40 miles offshore along Long Island 

 and southern New England showed a slight 

 increase. 



By May, larvae occurred only in the northern 

 half of the sampled region, and none were 

 found south of Delaware Bay (Figure 6). In 

 shallow tows, larvae were distributed in two 

 groups — one group within 15 miles of the 

 coast and the other group 5 to 40 miles off- 

 shore. Larvae occurred in deep tows only in 

 two areas — inshore off Martha's Vineyard and 

 offshore off western Long Island. Surface 

 temperatures were all above 7°C, and the 

 10°C isotherm was nearshore off New Jersey 

 and offshore of Maryland. Bottom temperatures 

 were about 3°C cooler than those at the 

 surface. Thus, larvae occurred in waters be- 

 tween 6° and 10°C. Apparently, temperatures 

 south of New Jersey, where larvae were taken 

 earlier in the year, were too warm in May. 



Most of the inshore tows from Massachu- 

 setts to Delaware were taken at night, which 

 might account for the apparent inshore abun- 

 dance but not the discontinuous distribution, 

 since intervening stations with no larvae 

 were also sampled at night. Water mass char- 

 acteristics and plankton distribution may have 

 been important factors in separating these 

 groups. Larval distribution is difficult to 

 relate to salinity distribution. In the past. 



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