422 



Fishery Bulletin 97(3), 1999 



130E 



150E 



170E 



170W 



150W 



130W 



110W 



Longline 



~^~~\ r 



Troll 



Longline 



U.S. baitboat 



It I L 



J I I I L 



130E 



150E 



170E 



170W 



150W 



130W 



now 



Figure 1 



Schematic diagram of geographic distributions of major North Pacific albaeore fishing fleets. 



3,000 -, 



1970 



1975 



1980 1985 



Year 



1990 



1995 



Figure 2 



North Pacific albaeore tag releases, by year. 



i 



tember, with 97% of the 23,780 releases occurring 

 prior to 1987 (Fig. 2). Tagging was carried out aboard 

 U.S. troll vessels and baitboats by NMFS technicians 

 and commercial fishermen trained in tagging. Tag- 

 ging methods are described by Laurs et al. (1976) 

 and Laurs and Wetherall (1981). Only albaeore 

 judged to be in very good condition were selected for 

 tagging; therefore mortality due to tagging is believed 

 to have been negligible. Tagged albaeore were re- 

 leased over a wide area of the eastern and central 

 North Pacific; the largest numbers of releases took 

 place in coastal waters adjacent to North America at 

 30°-50°N (Fig. 3). Fewer albaeore were tagged west 

 of 180°, which is the main operational area of the 



Japanese baitboat fleet. The size distribution of 

 tagged albaeore is t3T3ical of surface fishery catches 

 (Fig. 4). 



As of 14 August 1997, 1302 tagged albaeore (5.5% 

 of the releases) had been recaptured and the tags 

 returned to NMFS. Recaptures have been recorded 

 from a wide range of national fleets and gear types, 

 but the largest numbers of recaptures (68% of the 

 total) were made by U.S. and Japanese baitboats and 

 U.S. troll boats (Table 1). Recaptures occurred 

 throughout the North Pacific, but most recaptures 

 were concentrated in coastal waters adjacent to 

 North America (mainly U.S. troll and baitboats) and 

 west of 180° (Japanese baitboats) (Fig. 5). 



