Attachment techniques and retention of archival tags and PSATs on turtles, sharks, tunas and billfishes. Yonat Swimmer, U.H./PFRP Mike Musyl, U.H./PFRP Richard Brill, VIMS/NMFS
I. Archival tags deployed to date* 92 bigeye tuna 1 swordfish Total archival tags: 93 fish *PFRP/NMFS tagging programs: Brill, Musyl, Curran, Kazama, crew and officers of R/V Townsend Cromwell.
Archival tags are better placed in dorsal musculature Return rates of archival tags and conventional tags are similar (~15%). Placed in Body Cavity Placed in dorsal musculature
Cigar-shaped archival tags should not be placed in body cavity. Position of tag 4 days after implantation.
II. PSATS deployed to date* -- Sharks PSATS: 31 blue sharks 6 bigeye thresher sharks 3 shortfin mako 3 oceanic white tip sharks 25 swordfish 2 yellowfin tuna Total PSATs: 81 fish 1 bigeye tuna 8 blue marlin 2 black marlin *PFRP/NMFS tagging programs: Brill, Musyl, Curran, Kazama, crew and officers of R/V Townsend Cromwell.
Shark Harness
Retention of PSATs on sharks 43 sharks tagged to date 15 tags have reported early (i.e., before programmed jettison date) days at liberty ranged from 1-238 days, mean = 76 days, median = 56 days have data from 1,160 days in aggregate 24 tags still at liberty after 7 months 4 tags have failed to report
Harness consists of: 270# fluorocarbon line Stainless steel thimbles Braided stainless steel wire encased in heavy gauge tubing Breaking strength of eyelet on tag is 120# Tag shedding can be probably ruled out in the short term This tag/tether was out for 41 days No obvious abrasions or cuts caused by dermal denticles
Nuptial bites
PSATS deployed to date*--billfish & tunas PSATS: 31 blue sharks 6 bigeye thresher sharks 3 shortfin mako 3 oceanic white tip sharks 25 swordfish 2 yellowfin tuna Total PSATs: 81 fish 1 bigeye tuna 8 blue marlin 2 black marlin *PFRP/NMFS tagging programs: Brill, Musyl, Curran, Kazama, crew and officers of R/V Townsend Cromwell.
Swordfish are tagged in the water
Tunas are tagged on deck
Retention of PSATs on billfishes and tunas 25 swordfish, 10 marlin, and 3 tunas tagged to date 9 swordfish, 5 marlin, 3 tuna tags have reported early days at liberty ranged from 5-111 days, mean = 50 days, median = 33 days have data from ~ 600 days in aggregate 12 swordfish tags still at liberty after 7 months 4 swordfish tags have failed to report
Have used nylon and metal heads Nylon heads: mean retention = 39 days Metal heads: mean retention = 58 days **Of tags still at liberty on swordfish after 7 months, all are attached with metal heads
Recent modifications of tag head and tether (designed by Andrew West & Mike Musyl) Swivel added to tether to reduce torque of tag head in tissue Speargun barbs added to tag head to increase surface area (Currently deployed on 6 marlin)
Important points to consider when using metal tag heads Enough rubber bands to hold PSAT to tagging pole to ensure tag head toggles Relative position of tether to tag head on tagging pole Long enough (5 inch) tagging tip Nylon tips with speargun barbs may be easier to use!
PSATs deployed to date* -- sea turtles 7 olive ridleys 1 loggerhead 1 green 5 leatherbacks *PFRP/NMFS tagging programs: Swimmer, Lutcavage, Brill, Musyl, Arauz
We have used 2 types of marine epoxy Easy and safe to use on boat Base-plate and tag will float if tag is shed prematurely Retention rates appear independent of epoxy type
Using turtles maintained at the Kewalo Research Facility, PSAT remained attached for up to ten months
Observer Tag kit Observer tagging kit
Attachment Modifications for PSATs on Sea Turtles Original design To ensure that tag/baseplate would float upright at surface, we originally used a long (12 ) tether.
New design Swivel added to reduce torque (and reduce tether length) Braided steel line
Retention of PSATs on hardshelled turtles 9 olive ridleys, 1 green, 1 loggerhead 8 tags have reported early days at liberty ranged from 26-123 days, mean = 57 days, median = 41 days have data from 370 days in aggregate 2 tags still at liberty after 2-11 months 1 tag has failed to report
Leatherback attachment: use of rotator cuff anchor Mitek Products, A Division of Ethicon, Inc. (Johnson & Johnson) Titanium alloy Appears suitable as subdermal anchor for PSAT attachment Currently being tested on nesting leatherbacks in Puerto Rico by Molly Lutcavage, Anders Rodin, and Russ Andrews Retention rates appear similar (unknown yet) 2001 2002
Financial Support PSATs supplied by NMFS Honolulu Laboratory Salaries and field supplies supported by NMFS Honolulu Laboratory and the University of Hawaii (PFRP, JIMAR)