63 



Abstract — The recent development 

 of the pop-up satellite archival tag 

 (PSAT) has allowed the collection of 

 information on a tagged animal, such 

 as geolocation, pressure (depth), and 

 ambient water temperature. The suc- 

 cess of early studies, where PSATs 

 were used on pelagic fishes, has 

 spurred increasing interest in the 

 use of these tags on a large variety 

 of species and age groups. However, 

 some species and age groups may not 

 be suitable candidates for carrying a 

 PSAT because of the relatively large 

 size of the tag and the consequent 

 energy cost to the study animal. We 

 examined potential energetic costs 

 to carrying a tag for the cownose ray 

 iRhinoptera bonasus). Two forces act 

 on an animal tagged with a PSAT: lift 

 from the PSATs buoyancy and drag as 

 the tag is moved through the water 

 column. In a freshwater flume, a 

 spring scale measured the total force 

 exerted by a PSAT at flume velocities 

 from 0.00 to 0.60 m/s. By measuring 

 the angle of deflection of the PSAT at 

 each velocity, we separated total force 

 into its constituent forces — lift and 

 drag. The power required to carry a 

 PSAT horizontally through the water 

 was then calculated from the drag 

 force and velocity. Using published 

 metabolic rates, we calculated the 

 power for a ray of a given size to 

 swim at a specified velocity (i.e., its 

 swimming power). For each velocity, 

 the power required to carry a PSAT 

 was compared to the swimming power 

 expressed as a percentage, </rTAX (Tag 

 Altered eXertion). A %TAX greater 

 than 5% was felt to be energetically 

 significant. Our analysis indicated 

 that a ray larger than 14.8 kg can 

 carry a PSAT without exceeding this 

 criterion. This method of estimat- 

 ing swimming power can be applied 

 to other species and would allow a 

 researcher to decide the suitability 

 of a given study animal for tagging 

 with a PSAT. 



Quantification of drag and lift imposed 

 by pop-up satellite archival tags and 

 estimation of the metabolic cost 

 to cownose rays (Rhinoptera bonasus)* 



Donna S. Grusha 



Mark R. Patterson 



Virginia Institute of Marine Science 



College of William and Mary 



P.O. Box 1346 



Gloucester Point, Virginia 23062-1346 



E-mail address (for D. S Grusha): dsg@vimsedu 



Manuscript submitted 21 May 2003 

 to the Scientific Editor's Office. 



Manuscript approved for publication 

 13 July 2004 by the Scientific Editor. 



Fish. Bull. 103:63-70 (2005). 



The pop-up satellite archival tag 

 (PSAT) was developed in the late 1990s 

 primarily for the tracking of large 

 pelagic fish (Arnold and Dewar, 2001; 

 Gunn and Block, 2001). This electronic 

 tag is attached to a large fish, collects 

 data on the environment of the fish 

 for a preprogrammed period, and then 

 detaches from the fish by corrosion of 

 a release pin. A float on the tag car- 

 ries the tag to the surface of the water 

 where the PSAT begins transmitting 

 the archived environmental data. The 

 pop-up location is determined by the 

 Argos satellites that in turn transmit 

 the data to a relay station. The earli- 

 est uses of these tags have been on 

 large pelagic fishes such as Atlantic 

 bluefin tuna (Thunnus thynnus) (Block 

 et al., 1998; Lutcavage et al., 1999) 

 and blue marlin (Makaira nigricans) 

 (Graves et al., 2002). In the early tuna 

 studies, PSATs were used to investi- 

 gate geographic range and possible 

 stock structure. Graves et al. (2002) 

 used the tags to assess postrelease 

 survival of blue marlin from the rec- 

 reational fishery. Over their short his- 

 tory, the PSATs have been improved 

 to collect even more data than the 

 original models and currently record 

 light levels, temperature, and pres- 

 sure readings. The light levels are 

 used to estimate geolocation and the 

 pressure readings are converted to 

 depth measurements. Combined with 

 the temperature readings, the depth 

 measurements can provide detailed 

 information about the study animal's 

 swimming behavior. Experiences with 

 the first-generation tags led to the 



development of various fail-safe fea- 

 tures (Arnold and Dewar, 2001). Both 

 premature detachment (made evident 

 by the tag floating at the surface) or 

 lack of vertical movement (i.e., con- 

 stant depth, which indicates probable 

 death of the animal) initiate early 

 transmission of archived data. Should 

 the tag be carried to an extreme depth 

 where water pressure might physically 

 crush the tag, release mechanisms, 

 both software-based and mechanical, 

 have been developed to free the tag 

 from the animal. 



PSATs were developed to supple- 

 ment the tracking data that could 

 be acquired through acoustic tag- 

 ging and archival tagging. Acoustic 

 tagging is most useful for studying 

 fine-scale movement and habitat use 

 and for collecting physiological data 

 (Arnold and Dewar, 2001; Gunn and 

 Block, 2001). However, its use is lim- 

 ited by the need for labor-intensive, 

 real-time tracking from a research 

 vessel or the availability of fixed lis- 

 tening stations. Dagorn et al. (2001) 

 described clear interactions between 

 some of the yellowfin tuna (Thunnus 

 albacares) being tracked and the re- 

 search vessel — a violation of the as- 

 sumption that the tracking operation 

 does not alter the behavior of the fish. 

 Archival tags also collect both envi- 

 ronmental and physiological data but 



Contribution 2629 from the Virginia 

 Institute of Marine Science, College of 

 William and Mary, Gloucester Point. 

 VA 23062. 



