KENDALL and REINTJES: DISTRIBUTION OF ATLANTIC MENHADEN EGGS AND LARVAE 



ATLANTIC MENHADEN LARVAE 



CRUISE D-«6-12 



SEPT. 28 - OCT. 20, 1956 



were 8-12 mm in the northern part of the sampling 

 range, from New York north. Fish in a broader 

 size range, 4-12 mm, were present off New Jersey. 

 Nearly all fish south of New Jersey were smaller, 

 4-8 mm. 



In October the thermocline was breaking down 

 but still present over much of the area, and surface 

 temperatures were about 3°C cooler than in 

 August (Figure 6). Salinity values were about the 

 same as in August, mostly between 30.5 and 

 32.0''/oo, except near the mouth of Chesapeake Bay 

 where they dropped to 28.0''/<». 



The cruise in late fall 1966 (Figure 7) shows a 

 distribution pattern quite similar to the cruise in 

 December 1965 (Figure 8). During both cruises, 

 larvae occurred mostly nearshore from Long 

 Island to North Carolina. They were most abun- 

 dant near Cape Hatteras, where they were taken 

 to the edge of the shelf. 



In November 1966 there was a bimodal size dis- 

 tribution with one peak at 8 mm and the other at 

 20 mm (Figure 2). There were few larvae between 

 14 and 18 mm. In December 1965 the peak at 8 mm 

 is similar to that in late fall 1966, but the second 

 peak at 20 mm is not seen (Figure 2). Possibly this 

 difference is due to year-to-year variation in 

 spawning pattern in the area studied. 



In the November and December cruises, small 

 fish were found south of Delaware Bay and tended 

 to occur at least 12 km offshore. Larger fish oc- 

 curred mainly north of Chesapeake Bay and 

 mostly within 15 km of shore. In transition areas 

 between north and south and inshore and offshore 

 areas, fish in a wide length range occurred at the 

 same station and bimodal length-frequency curves 

 were seen. This may indicate that spawning occurs 

 in waves, and as the larvae grow they disperse 

 from the area where they were spawned. 



By late fall the thermocline was gone and sur- 

 face isotherms roughly paralleled the coastline 

 (Figures 7, 8). Larvae were taken over a wide 

 range of temperature, from 7° to 25°C. Most 

 collections were in water between 10° and 20°C. 

 Salinity varied considerably between the two late 

 fall cruises. In 1965, several patches of low saline 

 water, less than 30''/oo, were found mostly near the 

 shore (Clark et al. 1969). However, in 1966 salinity 

 throughout the area was greater than3lVoo,except 

 immediately outside Chesapeake Bay. The dis- 

 tribution of larvae is quite similar between these 



Figure 6.-Distribution and abundance of menhaden larvae and 

 distribution of menhaden eggs in the October cruise. 



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