NOTE Kerstetter et al.: Use of satellite archival tags to demonstrate survival of Makaira nigricans 



943 



100W 



90W 



sow 



70W 



60W 



SOW 



40W 



SON 



4SN 



40N 



3SN 



30N 



2SN 



20N 



15N 



ION 



65OT 63W" 



BERMUDA 



5D-5(103.7) 



SON 



45N 



40N 



3SN 



SON 



25N 



20N 



15N 



ION 



100W 



90W 



SOW 



70W 



60W 



SOW 



40W 



Figure 1 



Map showing points of release (squares) and points of pop-up (arrow tips at end of straight hnes) 

 for seven of nine blue marlin released from pelagic longline gear in the western North Atlantic 

 Ocean and equipped with pop-up satellite archival tags in 2000 and 2001. The tag identifier for 

 each fish and straight-line distance in nautical miles between point of release and location where 

 tag transmitted data to the Argos satellite are provided in parentheses. 



tion of the data), and the probabihty of recovering (i.e. 

 receiving) all the data recorded, as well as cost. The older, 

 less-expensive 5-day tags stored far fewer data points but 

 transmitted all of them. In contrast, the newer 30-day 

 tags captured far more detailed data, yet only transmit- 

 ted a fraction of them because of technological constraints, 

 such as a short battery life, file corruption, and occasional 

 problems with satellite uplink. Less than half of the 744 

 possible hourly histograms were recovered after final pro- 

 cessing (46.5% for 30D-1 and 47.6% for 30D-2). However, of 

 the reported histograms that were not corrupted, there was 

 fairly consistent reporting across hours of the day, with an 

 average of 14.75 records (range: 6-23) per hour of day for 

 30D-1 and 14.42 (range: 8-21) for 30D-2. 



The small data storage capacity of the 5-day tag provided 

 information regarding the thermal histories of blue marlin. 

 However, the frequency of temperature recording, and sub- 

 sequent averaging, limited the utility of the temperature 

 data alone to infer survival. In contrast, the 30-day tags 

 provided higher resolution data on temperature and depth. 



despite some significant gaps in the time series. In compar- 

 ing the two tag models used in this study, the less expen- 

 sive 5-day tags may be sufficient for the specific purpose of 

 evaluating survival, although the greater detail provided 

 by the 30-day tags may be desirable for additional behav- 

 ioral analyses. Several models of archival satellite tags 

 are currently available — all with differing data collection 

 and storage capabilities. The high costs of tagging-related 

 research, both for equipment and personnel time, therefore 

 require choosing the tag model that is best matched to data 

 needs to answer the specific scientific question of a study. 



Net movement 



All blue marlin tagged in this study undertook significant 

 movements (Table 2, Fig. 1). The blue marlin released 

 off Bermuda moved away from the islands 199.7 km 

 (107.8 nmi) in a southeast direction over five days. Graves 

 et al. (2002) noted similar movements away from the 

 tagging locations for blue marlin released from the recre- 



