562 



Fishery Bulletin 104(4) 



whereas the remainder of the hook-and-line releases 

 (618 fish) resulted in 49 recaptured fish (7.99H. This 

 difference may be attributable to less effective tags used 

 during 1963, rather than the capture method. All ALS 

 releases were fish caught with hook and line, but gear 

 type was not recorded for the recaptured fish. 



Tag types differed in rates of return and in time 

 fish spent at large. Return rates for NMFS tags were 

 similar between dorsal loop tags (760 of 10,752; 7.1%) 

 and internal anchor tags (310 of 4441; 7.0%). All NMFS 

 tagged fish recaptured after 17 months at liberty had 

 been tagged with internal anchor tags. Abrasion of some 

 dorsal tags occurred after two months and appeared 

 more severe on tags returned from Florida releases. 

 Some abrasion occurred on the external streamer of the 

 internal anchor tags. ALS dorsal loop tags resulted in 

 an overall return rate of 2.2%. 



Return rates for the NMFS tags varied by area, from 

 4.5% in New York to 10.2% from Florida (Table 2). 

 Eighty-three percent of recaptured tags that were at 

 liberty one year («=24) were from tagging in areas 

 north of New Jersey, and all recaptured tags at liberty 

 2, 3, and 4 years (10, 4, and 4 fish recaptured, respec- 

 tively) were also from tagging in these areas (Table 2). 

 For all areas combined, 51.3% of the NMFS recaptured 

 fish were at liberty less than one month and 88.1% 

 were at liberty less than five months. Among ALS tags, 



50.3%f were at liberty for two months and 79.3% for five 

 months or less. Only 4.5% of all returned fish were at 

 liberty greater than one year and 1.2% greater than 

 two years. The longest time-at-large for an ALS tagged 

 bluefish was 1461 days and 1486 days for a NMFS- 

 tagged fish. 



The size at release of the 36,097 tagged bluefish dif- 

 fered between the two programs. Fork lengths (FL) 

 ranged from 19 to 57 cm (7 to 22 inch) for NMFS and 15 

 to 114 cm (6 to 45 inch) for ALS (Fig. 2). The majority 

 offish released in the NMFS program (83.1%-) were 30 

 to 45 cm (12 to 18 inch) and were 1-, 2-, or 3-year-olds 

 according to estimates determined from scales from a 

 subsample of similar size fish collected during the tag- 

 ging operations. A greater size range of bluefish were 

 tagged in the ALS program, and 88.2% measured 30 to 

 76 cm (12 to 30 inch). 



Size frequencies of bluefish released, and of those 

 subsequently recaptured, differed despite the relatively 

 short times at large (Fig. 2). Changes in length can 

 be attributed to growth, unit conversion, and associ- 

 ated measurement error. The NMFS recapture data 

 set had 616 tag recoveries with appropriate fork length 

 and time-at-large information, whereas the ALS set 

 had 336 with these data (Fig. 3). The von Bertalanfy 

 growth parameter estimates from these data were L^ 

 of 100 cm and 118 cm (39 and 46 inch) for NMFS and 



