FISHERY BULLETIN: VOL. 73, NO. 2 



small larv^ae near their mouths. In winter they 

 were found at our southernmost stations. 

 Therefore, spawning could have taken place 

 inshore and offshore of our stations and farther 

 north and south of our sampling. 



Our results on area of spawning confirm the 

 conclusions of Higham and Nicholson (1964) and 

 Nicholson (1972) that menhaden spawn during 

 both their northward spring migration and their 

 southward fall migration. We conclude that 

 spawning apparently continues in winter in the 

 south, based on our catches around Cape Lookout. 

 Midsummer spawning may have occurred north of 

 our sampling area, or may have been inhibited in 

 1966 by water cooler than usual. 



Harrison et al. (1967) postulated that bottom 

 drift of waters off Chesapeake Bay influence the 

 success of year classes of menhaden. During years 

 when bottom drift was weak and southwesterly, 

 poor year classes occurred. However, our data and 

 that of Massmann et al. (1962) do not indicate a 

 preference for bottom waters by larger menhaden 

 larvae. Larvae entering the estuaries are found 

 throughout the water column (Lewis and Mann 

 1971), and later, in the estuaries, they are found 

 primarily in surface waters (Massmann et al. 

 1954). Possibly the factors affecting bottom drift 

 also affect the success of year classes, but in an 

 indirect way. 



Reintjes and Pacheco (1966) reported on inlet 

 and nursery area collections in Indian River, Del., 

 made over a 6-yr period (1955-61). Among the 

 years studied, the peak in larval abundance at the 

 inlet occurred in all months from December 

 through March. Larvae were taken at the inlet 

 from September through June in most years. It 

 appeared that when temperatures at the inlet 

 dropped to 3°C, larvae in the area were killed. In 

 four seasons, when large catches of larvae were 

 made at the inlet between December and 

 February and temperature later dropped below 

 3°C, larvae were scarce or absent in upstream 

 nursery areas. However, larvae taken in years 

 when temperature remained above 3°C and those 

 taken after the critical low temperature period 

 were later represented in collections upstream. 



Due to the extreme year-to-year variability in 

 time of entry at the inlet at Indian River, it is 

 difficult to relate our catches to these data. The few 

 small larvae taken near Delaware Bay in June 

 would probably have entered the estuary in July, a 

 month when Reintjes and Pacheco (1966) reported 

 none. We made large catches in this area in Oc- 



tober. Larvae were also present offshore in 

 November and December. In February, larvae 

 were not taken north of Virginia and water 

 temperature close to shore between Chesapeake 

 and Delaware bays was less than 0°C. From these 

 data, it would appear that 1965-66 was dissimilar 

 to any year studied by Reintjes and Pacheco (1966) 

 with regard to menhaden larvae near Delaware 

 Bay. Presumably during 1965-66 larvae could have 

 been taken in abundance in late fall but would 

 have been killed by cold water in February. Sub- 

 sequently no larvae would have entered in winter 

 or spring, but some might have appeared in early 

 summer. 



Menhaden larvae were taken off Chesapeake 

 Bay in waters 1° to 15°C by Massmann et al. 

 (1962). Herman (1963) reported them in 

 Narragansett Bay from 1° to 22°C. The larvae we 

 collected at temperatures below 3°C did not ap- 

 pear decomposed as would be expected had they 

 been dead when captured. Lewis (1965, 1966) has 

 studied the effects of subjecting menhaden larvae 

 to low temperatures and a range of salinities in 

 the laboratory. He has shown that moderate 

 salinities (10-20''/i)o) enhance survival at low 

 temperature as do lowered acclimation tempera- 

 tures. At 7°C acclimation temperature, the lowest 

 he used, and 2° to 4°C test temperatures, 50% 

 mortality occurred in about 40 h at 24"/oo. Salinities 

 in our areas of capture were 31 to SS^/w-higher 

 than those tested by Lewis (1966). If temperatures 

 below 3°C in estuarine waters kill many 

 menhaden (Reintjes and Pacheco 1966), it may be 

 advantageous for larvae to remain in the ocean 

 where temperature changes are more gradual. 

 Menhaden entering estuaries are usually larvae 

 less than 30 mm long, and in the estuary they 

 rapidly transform by 38 mm (Lewis et al. 1972). 

 Reintjes and Pacheco (1966) reported a few trans- 

 forming specimens (greater than 34 mm) entering 

 Indian River in May. That they are dependent on 

 estuarine conditions for transformation is sup- 

 ported by the absence of transforming specimens 

 and juveniles in our collections. 



SUMMARY AND CONCLUSIONS 



A total of 7,006 menhaden larvae were collected 

 in 172, 0.5-h Gulf V plankton tows. The larvae were 

 taken on eight cruises along the middle Atlantic 

 coast throughout the year. Eggs were taken in a 

 few tows in the fall. The catch distribution was 

 nonnormal, with 48 tows catching only 1 fish and 1 



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