566 



Fishery Bulletin 104(4) 



of seasonal recaptured fish (Fig. 6) further highlighted 

 the pattern of a northerly migration that began in May 

 and was followed by southerly migration beginning in 

 December. However, the entire coastal stock did not 

 make the seasonal shift. Bluefish released in southern 

 Florida were recaptured locally during the summer resi- 

 dency period and other fish tagged in southern Florida 

 appeared in coastal New Jersey (Table 3). 



Seasonal distribution data from bluefish tag returns 

 indicated a southward movement of fish during the 

 fall, culminating in an over-wintering aggregation near 

 Cape Hatteras, North Carolina, and to the south. Com- 

 mercial catch records from the Middle Atlantic for 2001 

 to 2003 indicated a greater seasonal inshore-offshore 

 movement than that implied from tag recoveries. Ves- 

 sel logbook data indicated that bluefish are present in 

 the northern and central areas throughout the winter 

 and have an increasingly offshore and southern distri- 

 bution as water temperatures decrease. By March, the 

 commercial catches increase off the coasts of Virginia 

 and North Carolina (Fig. 7). The sizes of fish in these 



16 -1 

 14 



111 -I 



E 



g 



C/3 



 Nonh 

  Central 

 A South 



Mean speed 





h 



* * * 



i i 



100 

 80 - 

 6(1  

 4(1  



;ii 







 North 

  Central 

 ▲ South 



Days at large 



^•»M 



 « » 



M 



•^ 



^ V?' a^' v«^'■ S?' tf" kS^' -x^' # cp> 

 Length (cm) 



Figure 5 



Mean swimming speed, days at large, and distance traveled (±95'7r con- 

 fidence interval) by length for bluefish (Pomatonuis saltatrix) sampled 

 in National Marine Fisheries Service and American Littoral Society 

 tagging programs. 



commercial catches were generally larger than those 

 of tagged fish; lengths were between 25 and 70 cm and 

 mean size was 45 cm. The commercial catch distribu- 

 tion expanded northward beginning in April, in a direc- 

 tion similar to the bluefish migratory route indicated by 

 spring tag returns. 



Discussion 



A generally established hypothesis for bluefish migration 

 is that fish undergo a seasonal coastal migration, leaving 

 the Mid-Atlantic Bight in autumn as water temperatures 

 decrease and moving as far south as Florida. In spring, 

 bluefish return north where they spend the warmer 

 months in habitat suitable for larger, mature fish — 

 possibly in habitat extending across the continental shelf 

 (Wilk, 1977; Fahay et al., 1999). Our hypothesis expands 

 that migration pattern to suggest there are three bodies 

 of fish with different migration behaviors. One group 

 has an extensive north-south migration between New 

 England and Florida, a second group 

 has a migration route within the Mid- 

 Atlantic Bight bounded to the south by 

 North Carolina, and a third group has an 

 inshore-offshore migration within Florida 

 waters. The geographic ranges of these 

 three groups overlap during at least part 

 of the year and the seasonal areas of dis- 

 tributions change with fish size. 



Bluefish from Massachusetts to Dela- 

 ware (northern region) leave the coastal 

 areas in autumn, and fish less than ap- 

 proximately 45 cm (18 inch) migrate south 

 along the coast and are found in the south 

 Florida winter fishery. However, tag re- 

 turn data indicate that part of this size 

 group, as well as all fish over 45 cm (18 

 inch), move offshore in autumn and are 

 distributed during winter in offshore ar- 

 eas south of Virginia. Both size groups 

 return to the northern area in spring and 

 summer a year after tagging, as well as 

 in successive years. 



The Mid-Atlantic area from Maryland 

 to North Carolina (central region) appears 

 to be a transitional area in the migratory 

 route. A group of fish tagged in the north- 

 ern region migrated in fall to the central 

 region and remained throughout the win- 

 ter, whereas other fish continued south 

 to Florida. In the spring, a portion of the 

 Florida fish moved back to the central 

 region, while others continued through to 

 the northern region. The distribution of 

 commercial catches reported in logbooks 

 confirmed the movement of bluefish in- 

 to offshore waters during autumn, and 

 movement increasingly south as winter 

 progresses. The reported landings of large 



