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Instructions for the implantation of the LAT 2810 into the peritoneal cavity of tunas

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Kurt M. Schaefer and Daniel W. Fuller
Inter-American Tropical Tuna Commission
La Jolla, California

The LAT 2810 tag with the external light/temperature stalk configuration is designed for implantation into the peritoneal cavity of tunas or other fishes. The design, along with the following instructions, should enable anyone to easily apply these tags after a limited amount of practice and experience. A new methodology is described below in which the external light/temperature stalk exits through a secondary hole, so that the initial incision to accommodate the tag body within the peritoneal cavity can be completely closed with sutures, to as prevent shedding of these relatively small archival tags.

Materials and Methods

  1. The following sterile needle and suture material (Ethicon (PDS II) size 0, cutting cp-1, 70 cm), should be used for closing the incision in the ventral abdominal wall through which the LAT 2810 is to be implanted in the peritoneal cavity. The end of this suture material, without the needle attached, should be carefully tied in advance to one of the wire connectors on the tags.
  2. Following capture, the fish should be placed immediately with its ventral surface directed upward, into a padded v-shaped cradle which is covered with a smooth and wet vinyl liner. The fish should be immediately examined to confirm that it is in excellent condition before beginning the tagging process. If there is no excessive bleeding from the mouth and no apparent damage to the gills and/or eyes, the fish should be considered suitable for tagging. Following this rapid evaluation, the head and eyes of the fish should be covered with a wet synthetic chamois cloth. The fish should be gently restrained by one person, while another person applies the tags. Those two individuals should stand on opposite sides of the tagging cradle facing one another. We do not irrigate the gills of the fish by placing a hose with running water in the mouth of tunas.
  3. The identification number of the LAT 2810 and the accompanying Hallprint plastic dart tag (PDT), along with the species, and length of the fish, should be recorded.
  4. The person applying the tag should be wearing a pair of new sterile Nitrile gloves for each tag to be implanted.
  5. An incision about 2 cm long should be made in the abdominal wall anterior of the anus and about 2 cm to the left of the centerline of the fish. Special care to be taken to cut only through the dermis and partially through the muscle, but not into the peritoneal cavity. A gloved finger is inserted into the incision and forced through the muscle, with a twisting motion, into the peritoneal cavity.
  6. The tag body should be sprayed with Betadine solution using a squirt bottle, at this stage in the process, to partially sterilize.
  7. A new sterile10 gauge stainless steel curved piercing needle, is carefully manipulated inside the incision and with the pointed end pushed through the abdominal wall about 1 cm posterior to the initial incision so as to penetrate outside. When about ½ of the needle is protruding you stop and place the end of the external stalk of the LAT 2810 inside the end of the piercing needle and then push the needle entirely through and remove from the stalk. The stalk is then pulled to the point at which the relieve spring will not easily pass, and with a hard pull the relieve spring will penetrate through the abdominal wall.
  8. The tag body while being held by the thumb and index finger is now inserted, anterior end first, through the initial incision, into the peritoneal cavity. This requires bending the tag stalk in nearly a 180 degree bend at the spring relieve section of the tag. The tag stalk is then pulled gently until the tag body is directly beneath the initial incision and the spring relieve section is mostly protruding outside the fish. With the suture material previously attached to a connection wire of the tag body, two sutures are placed to tightly close the incision.
  9. It is also recommended that a PDT be implanted at the base of the second dorsal fin. The PDT should have a label indicating the amount of money being offered for the return of the LAT 2910 PDA implanted in the fish. It should also contain the information for making contact with the organization to whom the tags are to be returned.
  10. The person who has been restraining the fish should now remove the synthetic chamois cloth from the head of the fish. At the same time the other person whom implanted the tag should place one hand under the head and the other hand under it’s caudal complex and quickly toss the fish from the cradle back into the sea.
  11. This process from the time the fish is placed in the cradle until it is released back into the sea can be completed within about 2 minutes.

Watch a video demonstrating this technique.

Go to: Instructions for the intra-muscular implantation of the LAT 2910, equipped with a plastic dart anchor (PDA), at the base of the second dorsal fin in tunas