KENDALL and WALfORD SOURCES AND DISTRIBUTION OF BLUEFI! 



,1 ' 



18- 



23 



36 81 5 



1147 



256 



7 

 1 18 



1 1 3 



- 1 22 11 



19 2 48; 41 



1 3 223; 18 



^193 1 



3 



14 



NUMBER OF TOWS 



1 ^ 



33 3! 



SALINITY %■> 

 1- 



1-n 



S-9 



10-19 



>19 



FIOURE 6. — Clustering of catches of larval bluefish by temper- 

 ature-salinity combination during RV Dolphin surveys, 1965- 

 68. Numbers of bluefish larvae superimposed on temperature- 

 salinity combinations where they were caught. 



Table 3.— RW Dolphin 1965-68 ichthyoplankton survey. A com- 

 parison of bluefish larval catches during day and night. 

 Number of tows 



offshore seasonal geographic distribution of 

 bluefish juveniles indicates a complex pattern of 

 movements from offshore spawning areas to 

 coastal and estuarine nursery areas. 



In summary we found bluefish juveniles, pre- 

 sumably from the spring spawning, at the surface 

 near the slope front from south of Cape Hatteras to 

 off the Middle Atlantic Bight in April to June 

 (Figure 1). We hypothesize that they move north- 

 ward along the slope front, then cross the shelf, 

 enter estuaries of the Middle Atlantic Bight and 

 after spending the summer in the estuaries, re- 

 turn to the sea and move southward along the 

 coast and out of the Middle Atlantic Bight. Some 

 juveniles from the summer spawning in the Mid- 

 dle Atlantic Bight remain in coastal waters while 

 some enter estuaries briefly. They too leave the 

 Middle Atlantic Bight in early fall. The following 

 is our evidence for these conclusions. 



In May 1967, juvenile bluefish were scattered 

 over the continental shelf in the South Atlantic 

 Bight and north to Cape Hatteras (Figure 7). The 

 largest specimens were from stations near shore. 



In April and May 1971, we sampled the offshore 

 area intensively around Cape Hatteras to find any 

 trace of young bluefish which could be attributed 

 to larvae and juveniles such as had appeared pre- 

 viously to the south. During this cruise neuston 

 tows took bluefish juveniles near the edge of the 

 continental shelf ( 100-fm (183-m) isobath) (Figure 

 8a). All of the specimens taken were in water 

 >15°C, which occurred all across the shelf south of 

 Cape Hatteras, but only near the edge of the shelf 

 north of there. 



In the June 1966 survey, when 59 stations were 

 sampled, bluefish appeared at each of two widely 



Table 4.— RV Dolphin ichthyoplankton surveys 1966-68. Length distributions of larval bluefish collected in Gulf V samples. 



221 



