KENDALL and WALFORD SOURCES AND DISTRIBUTION OF BLUEFISH 



BLUEFISH LMVAE 



* -P CRUISf D -66 -S 



MAY 12-24, 1966 



AA -PP; CRUISE 0-67-4 

 MAY 7 - 15, 1967 



SELECTED SUFACE 

 1SOTHBMS ( "C 1 



surface temperature patterns affected the catch 

 rate. Large catches just shoreward of the Gulf 

 Stream followed periods of northerly winds which 

 caused a compression of surface isotherms in this 

 area. Following southerly winds the isotherms 

 were spread out and catches were low. It thus 

 appears that the catch rate was related to the 

 width of the band of suitable water, and that in 

 turn was related to wind conditions. 



No bluefish larvae were collected in the Middle 

 Atlantic Bight in January, April, May, and June 

 1966, but they were abundant and widespread in 

 August when their distribution extended from east- 

 ern Long Island, N.Y., to Virginia and more or less 

 over the breadth of the continental shelf (Figure 

 3). They were most abundant off New Jersey and 

 Delaware. Most of these larvae were small (mean, 

 4.0 mm SL) indicating that spawning had occurred 

 not long before this cruise. The relative number of 

 fish <4 mm SL was gi-eatest at the northern end of 

 the survey area and diminished progressively 

 southward to Delaware Bay ( Figure 4 ). This effect 

 could have resulted from growth of the larvae dur- 

 ing our sampling from north to south in this area 

 over a 3-day period. It also might have resulted if 

 bluefish spawning had started in the south and 

 progressed northward. Either or both of these pro- 

 cesses may have been involved. There was an 

 11-day gap in sampling between Delaware Bay 

 (Transect F) and Maryland (Transect G). This 

 might account for our finding so few, but larger 

 larvae south of Delaware Bay. 



Bluefish spawning in middle Atlantic waters 

 was almost finished by the end of summer, judging 

 from the paucity of specimens taken during Sep- 

 tember and October (Figure 5). In September, 

 when we sampled only north of middle New Jer- 

 sey, we caught two larvae; and in October, when 

 the sampling area extended over the whole Middle 

 Atlantic Bight, we again caught two. We have no 

 information on the southerly extent of bluefish 

 larvae during September, since there was no sam- 

 pling south of New Jersey then. 



Four bluefish larvae were taken during winter 

 cruises, one at each of four stations near the edge 

 of the continental shelf. One was taken off North 

 Carolina ( Transect N) and the other three between 

 St. Augustine, Fla., and Palm Beach (Transects Y, 

 KK, and LL). 



Figure 2.— Distribution of surface temperatures and larval 

 bluefish in May. Transects A-P sampled May 1966; AA-PP sam- 

 pled May 1967. 



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