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As part of the 19th Annual Symposium on Sea Turtle Conservation and Biology, South Padre Island, Texas, this lunchtime session served as a very brief introduction to satellite technologies and sea turtle research.

The Chair (Emma Hickerson) selected four topics for discussion: transmitter attachment, transmitter duty cycle, antenna integrity, and location accuracy. There was a three person panel: George Balazs, (NOAA/NMFS, Marine Turtle Research Program, Honolulu, Hawaii), Barbara Schroeder (National Sea Turtle Coordinator, NOAA/NMFS) and Richard Byles (unaffiliated). As each topic was presented, each member of the panel was invited to comment, and the floor was opened up for questions. The first topic took up the majority of the time, with little discussion covering the remaining topics.

Transmitter Attachment: Richard Byles commented that he uses a two-part epoxy for attachment. He noted that he has tried other methods including tethering the transmitter encased within a float and the transmitter tended to leak. He commented that he currently uses the backpack mount method. Barbara Schroeder commented that she also uses this method, which uses silicon elastomer for the base in combination with a polyester resin and fiberglass cloth to secure the transmitter to the carapace.

The time it takes to attach the unit is approximately 2.0-2.5 hours. George Balazs noted that this method was developed with input from Sally Beavers and Russ Miya (Balazs et al. 1996) which was tested at Sea Life Park in Hawaii for thirteen months with captive turtles. The key element is the silicon elastomer base a safe, cold curing, human medical compound. He also added that the polyester resin, while not cold-curing, is applied in very thin layers and hence does not generate any appreciable heat. He also noted that the elastomer provides a level surface for attachment of the transmitter and that the elastomer also allows for easy removal of the transmitter, if recovered, by using a hack saw or similar tool to cut along the layer of silicone elastomer base and then lifting the transmitter off the carapace. No problems had ever been encountered with the attachment time necessary. Green turtles in Hawaii have been documented basking for up to 11 hours.

Sally Murphy commented on a satellite attachment method developed by Gray's Reef National Marine Sanctuary: 2 part steel reinforced putty (Sonic Weld) used in conjunction with a 2 part epoxy (Foil Fast) made by Rawl. (Mitchell in press) If the opportunity to recapture the animal arises, a plastic paint scraper is used to remove the transmitter from the carapace. George Balazs provided a cautionary warning that most 2 part epoxys can potentially cause severe burns at the catalytic point. He also warned that when researchers are attempting to duplicate a method, they should not substitute brands and pointed out that size appropriate transmitters should be used based on the size of animal. It was noted that Kennard Watson and colleagues have shown that hydrodynamics of transmitters is important and have recently published their results (Watson & Granger 1998). it was noted that Pam Plotkin uses the fiberglass/resin technique, but uses fiberglass pipe insulation cut to size to fill air spaces with resin.

Duty Cycles/Repetition Rates: It is important to take into consideration diving behaviour of the animal when programming a platform. If a researcher wants a duty cycle different from normal, they need to talk to the manufacturer. The cycle combinations need to be 12 hour combinations. In addition to this, it is important to note that repetition rates vary.

Antenna integrity: It was suggested that reversing the position of transmitter (facing aft) may extend the life of the antenna, but if the angle of the antenna is too low the signal may be attenuated.

Transmitter Choice: Phillippe Roche, the Director of Information Technology at ARGOS, commented that ARGOS has certified close to 20 manufacturers of transmitters. He noted that Telonics is the primary manufacturer for animal tracking. He suggests that when a researcher is getting ready to deploy a transmitter, they should ask the manufacturer for a satellite prediction chart. Researchers can also check on the ARGOS website for that information. There are other sources on the web for satellite predictions.

Online Discussion: It is intended that this initiative be continued as an online forum to allow further discussion regarding these and other topics of related interest. Please contact Emma.Hickerson (details above) for inclusion on the online discussion group.

BALAZS, G.H., R.K. MIYA & S.C. BEAVERS. 1996. Procedures to attach a satellite transmitter to the carapace of an adult green turtle, Chelonia mydas. In: J.A. Keinath, D.E.Barnard, J.A. Musick & B.A. Bell (Compilers). Proceedings of the 15th Annual Symposium on Sea Turtle Biology and Conservation, Feb. 20-25, 1995, Hilton Head, SC. NMFS-SEFSC-387 pp. 21-26.

MITCHELL, S.V. In Press. Use of epoxy in telemeter attachment. Proceedings of the 18th Annual Symposium on Sea Turtle Biology and Conservation, March 3-7, 1998, Mazatlan, Sinaloa, Mexico.

WATSON, K.P. & R. A. GRANGER. 1998. Hydrodynamic effect of a satellite transmitter on a juvenile green turtle (Chelonia mydas). Journal of Experimental Biology. 201(17): 2497-2505