- Date – Date fish is released
- Location – Provide the Latitude and Longitude position where the fish was released. Record Loran TDs for location only as a last resort.
- Fish Fork Length – This is measured in a straight line from the tip of the nose to the center (shortest point) in the fork of the tail. Please note if you estimated the length or physically measured the length. This is important.
- Fish’s Sex – Note the sex of the fish only if it is clearly apparent to you.
- Water Temperature – If you have electronics that measure the water temperature, please provide that information and note that it is measured. Estimated temperatures or those from electronic units known to be defective are of little value.
Sargassum Quantification Instructions
Note: Because of the dolphin’s high level of mobility, all sargassum quantifications relate to what is visible within a 1,000-foot radius of the catch site.
Present or Absent - One piece, one square foot in size, indicates sargassum is present.
- Line(s) – A form that is at least 100 times longer than its greatest width and may occur in multiples.
- Patch – An assemblage that is less than 100 sq. ft in size whose length is less than 100 times the greatest width.
- Raft – An assemblage greater than 100 sq. ft. in size whose length is less than 100 times the greatest width.
- Dispersed – Clumps/pieces with open water separating them may be as little as 2 to 3 inches of open water.
- Moderate – Majority of clumps/pieces are touching, few open water lesions visible. Grass usually extends down over 4 inches thick.
- Solid – Virtually all clumps/pieces are pushed together with almost no open water showing and extend 6 inches or more under water.
Quantity - amount present by surface area covered. Indicate amount in the appropriate box designation:
A = less than 100 sq. ft. B = 100 to 1,000 sq. ft. C = more than 1,000 sq. ft.
How To Tag Dolphinfish
The value, integrity, and credibility of this study rest in the recording of the field data. The quality of the information that you provide will decide the value of the recovery of your tagged fish.
Tagging Small Dolphin
This is a scientific study and accurate data are essential for the project to succeed. Without accurate data to define the tagging event, it is of little value. Completed tag cards need to be returned promptly so they are not lost. Also the goal is to release healthy fish. If a fish is gut-hooked, hooked in the gills, or in an eye, do not tag it. Understand this is work; the fish are not going to be willing participants.
Contrary to popular belief, data from fish that are tagged and never recovered are extremely valuable in gathering information about the species. Information from each fish tagged will help define the recreational fishing grounds, the temporal and spatial occurrence of the species, relationship of the species to sargassum, and inter-relationship between ocean current features and dolphinfish occurrence.
Anglers should never try to tag a small dolphin while the fish is in the water or dangling from the hook. This is not a good practice. Attempting to implant the nylon dart tag into small fish not fully under control could result in poor tag placement. Tags are easily lost out of the applicator when using the hand applicator on fish in the water. Proper insertion of the tag into the fish's back muscle requires the fish to be against a solid surface and immobilized. The first step toward correctly tagging dolphin is to have the tag in the applicator, a wet towel and a measuring device ready before the fish is brought into the boat. Place the wet towel over the fish's eyes while it is still hanging from the hook. Lay the fish on a wet, smooth, flat surface with the measuring device under it or immediately adjacent. Such a surface reduces slime loss while the measuring device allows for a quick, accurate length assessment before the fish is returned to the water. The final step in tagging a dolphin should be to complete the pertinent information requested on the field data card: date, latitude and longitude, fish’s length, water temperature and whether Sargassum is present.
The starter tag kit includes instructions for assessing Sargassum quantities, a tag applicator and five uniquely numbered tags on matching postage paid field data cards. Anglers are sent additional tags as they send in their completed cards.
Information Needed on Tagged Fish
Field Tagging Data Card
Tagging fish in the water.
To properly tag dolphin in the water beside the boat requires patience and the philosophy that if the fish gets off before being tagged, it is no big deal. As soon as the fish comes to the boat, you should determine where the fish is hooked. If it is hooked in an eye, the gills or stomach, it should not be tagged. The absolute worst thing is to jab wildly at a thrashing fish. This commonly results in a tag placement that is fatal to the fish. The boat should continue idling ahead to force the fish to swim beside the boat with its head toward the bow. The person doing the tagging should position himself along the gunwale between the person holding the leader and the stern. This provides the most open access to the fish. Wait for the fish to calm down to where it swims on its side in a stable position. Quickly position the applicator so that the needle is pointing to the place where you want to implant the tag holding the needle point about 2 to 3 inches above the fish. When the fish is not moving, use a short, quick jab to implant the tag. The tag should be inserted in the dorsal (back) muscle mid-way between the spine and the base of the dorsal fin from 1/4 to 1/2 the fish’s body length back behind the head.
The Desired Results
Loading Scientific Tags into the Applicator
Place a tag in the applicator prior to catching a fish that you may wish to tag. Keep the tag’s corresponding card in a secure spot where it will not blow overboard or otherwise get lost. Leave the plastic point guard on the applicator’s point to protect it from damage and prevent personal injury.
The correct way to load the tag into the applicator is to insert the tag’s streamer into the needle opening
and slide the tag into the needle until the barb rests against the back edge of the needle’s point.
Place the tag in the back musculature from 1/4 to ½ the fish’s body length behind its head. The applicator should be inserted at a 45o angle toward the head of the fish with the plastic tag bard facing down toward the fish and its trailing tip pointing toward the fish’s tail. Insert the applicator point deep enough to allow the barb to pass between the spines that radiate off the top of the backbone at the midline of the back. This permits the barb to lock around one of the spines ensuring that the tag will not be shed. Take not to hit the fish’s spine, which will cause paralysis. Typically ¾ to 1 ½ inches of the tag head should be buried in the fish. As a final step give a light tug on the tag to make sure that it is securely implanted.
Construction is simple and quick.
- Step 1. Drill a 1/8th in. hole through the center of the pipe 4 1/2 inches from one end. Insert the bolt and secure it with the nut. A dab of silicone caulk on the bolt threads will keep the nut from backing loose in the future. Place a small amount of silicone on the inside wall of the end cap for an adhesive and slip it onto the other end of the pipe.
- Step 2. Apply a moderate coating of silicone to the wire or plastic rod leaving 1 in. clean to hold it by. Slowly insert the wire into the applicator needle where the tag goes. Spin the wire inside the needle to ensure that you get a thin coating on the inside of the needle. This coating will provide a little friction to the tag to keep it from falling out when the applicator is pointed downward during tagging. Caution: too much silicone in the needle will prevent the tag from being fully inserted into the needle.
- Step 3. Wrap a single layer of duct tape around the top of the wooden handle opposite from the needle. The tape should provide enough additional friction to hold the applicator up inside the pipe while tagging the fish. If the applicator is still loose in the pipe with one layer of tape, add a second layer of tape.
- Step 4. Slide the applicator into the pipe until it rests firmly against the bolt. The needle should extend 2 1/2 in. beyond the pipe. You now have an in-water tagging stick.
Al Fernandez recaptured this bull off Miami, Florida in January 2008. It had been tagged by Scott Frost off West Palm Beach, Florida, 23 days prior.
Should you have any additional questions regarding tagging dolphinfish,
contact the research program’s office.
Donald L. Hammond
Marine Fisheries Biologist
Cooperative Science Services, LLC
961 Anchor Rd.
Charleston, SC 29412-4902
® Copyright 2005-2014 Cooperative Science Services, LLC
Many anglers who are currently tagging their small dolphin for this research program would occasionally like to be able to tag big dolphin safely. Fishermen who regularly fish offshore occasionally encounter days when their fish box is not large enough for all of the big dolphin they’re catching, or they are tired of cleaning fish and do not want to bring any fish to the dock. At these times participating taggers would like to have a little longer tag applicator to tag the fish in the water. Any angler who has fished offshore for any length of time has learned that a 36-inch dolphin can slap the fool out of you when trying to handle it.
There is a simple solution that allows you to instantly convert a handheld applicator into one for use on fish beside the boat and then return to using it as a handheld. It only requires a piece of PVC pipe, a plastic end cap, one bolt, a short length of duct tape and just a dab of silicone. An additional plus is that it will not rust or corrode in saltwater.
- Power drill with 1/8th in. bit (not shown)
- 1 – small tube of silicone caulk (A)
- 1 – 3 to 4ft ¾ in. PVC schedule 40 pipe (B)
- 1 – plastic end cap to fit ¾ in. pipe (not shown)
- 1 – standard dolphin tag applicator (C )
- 1 – 3 in. length duct tape (D)
- 1 – 1/8th in. diameter X 1 ¼ in. stainless steel bolts with nut (E)
- 1 – 7 in. long wire or piece of plastic 1/16th in. diameter. (F)
- Finished applicator for large fish. (G)
Made possible by a grant from the Guy Harvey Ocean Foundation.