564 



Fishery Bulletin 104(4) 



ALS, respectively, and K values of 0.230 and 0.206, 

 respectively. The 95% confidence interval around L^ 

 for the NMFS data ranged from 79 to 121 cm (31 to 48 

 inch) and ALS estimates ranged from 95 to 141 cm (37 

 to 56 inch). Confidence intervals for the K parameter 

 ranged from 0.135 to 0.324 for the NMFS data and 

 0.109 to 0.303 for the ALS data. 



A single vector drawn between tag release and re- 

 capture locations represents the shortest possible wa- 

 ter route traveled between the two points. The actual 

 route of travel likely diverts from this path; however it 

 remains the basis for determining distance traveled. 

 Movement of bluefish between western Long Island 

 Sound and lower New York Bay through the East River 

 was not indicated by the tag return data, and therefore 

 passage of bluefish through the East River was not 

 considered in the distance calculations. Seventy-five 

 percent of the NMFS tags were recaptured within 100 

 km of the tagging location; whereas 9.7% were caught 

 350 km or farther from the tagging area. The maximum 

 distance traveled was 2227 km (Chesapeake Bay to 

 west Florida) for a fish at liberty 341 days (6.5 km per 

 day). For the ALS recaptured fish, 59.7% were recap- 

 tured within 100 km of the point of release and 40.3% 

 (187) traveled beyond 100 km averaging 295 km, and 

 45 bluefish traveled more than 400 km. The maximum 



NMFS 



800- 

 400 





 Release (n=1 5, 699) 

 D Recapture (n=325) 



Mrt^ rflJInn 



ALS 



Release ( n=20,398) 



r □ Recapture (n=202) --20 



() -I— ^^^M J I M | M M |l M 1 ,1 M 1,1 I I 1,1 M [7rn __^ 



Fork length (cm) 



Figure 2 



Frequency distributions for release and recapture fork lengths of bluefish 

 (Pomatomus saltatrix) sampled in National Marine Fisheries Service 

 (NMFS) and American Littoral Society (ALS) tagging programs. 



distance was 1096 km for a fish at liberty for 76 days 

 (14.4 km/day). 



The number of days at liberty represents the maxi- 

 mum time possible for a fish to travel the straight-line 

 distance between the tagging and recapture locations. 

 Movement was generally less than 5 km per day (84.3% 

 of recaptures) and the overall average speed of fish 

 recaptured in both programs was 2.6 km per day. Sev- 

 enteen bluefish traveled more than 20 km per day and 

 had a maximum swimming speed of 48.3 km per day 

 for three days. 



The average swimming speeds for combined NMFS 

 and ALS recaptured fish were significantly different 

 among months (P=0.02). Speeds were highest during 

 the autumn, peaking during October-November at 

 5.3 km per day, and there was another spike during 

 April-May at 4.9 km per day (Fig. 4). These seasonal 

 peaks were in contrast to the overall average of 2.6 km 

 per day. Seasonal variations in swimming speed were 

 considered indicative of periods of active migratory 

 behavior. This annual cycle of movement was divided 

 into four periods based on the average rate of travel for 

 each month: winter residency (December to February), 

 spring migration (March to May), summer residency 

 (June to August), and autumn migration (September 

 to November). 



The swimming speed and distance trav- 

 eled during seasonal movements were dif- 

 ferent for all bluefish size groups. Swim- 

 ming speed offish 30-45 cm (12-18 inch) 

 was greater than speed of fish 45-65 cm 

 (18-26 inch) and this pattern was con- 

 sistent across regions (Fig. 5). The speed 

 disparity by size was influenced by the 

 distance traveled, not by differences in 

 time-at-large because the data were lim- 

 ited to recoveries within 90 days. Smaller 

 bluefish, particularly those released in 

 the northern region, traveled farther dis- 

 tances on average than fish in the larger 

 size classes (Fig. 5). 



Movement of tagged fish among areas 

 is a function of both the behavior of the 

 animal and adequate time-at-large to 

 exercise that behavior. Half (229 of 459 

 fish with location information) of bluefish 

 tagged with ALS tags were recaptured 

 beyond the state of release; the remain- 

 ing recaptured fish were caught in the 

 area of release (Table 3). NMFS releases 

 had a higher proportion recaptured blue- 

 fish within the state of release (77.1%; 

 Table 3). Most long distance returns oc- 

 curred during the first year after tag- 

 ging; recoveries in years 1 through 4 af- 

 ter tagging were generally from the area 

 of release (62 of 100) or in the release 

 area and adjacent areas (91 of 100). Fish 

 recaptured from New Jersey northward 

 accounted for 89 of the 100 recaptured 



■■20 



-- 10 



