Tagging Procedure

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HOW IT WORKS

During the tagging procedure the fish can usually be held in a suitable tagging position along side the boat by holding the leader over the side at the forward end of the cockpit (as seen below) while idling slowly ahead. The fish should not be removed from the water and handled only out of necessity by the bill. The tag is now inserted until the stopper is pressed against the fish. It is important that the tag is placed in the proper tagging area (as indicated right). It is not necessary to use a great deal of force to insert the tag. A firm, well- aimed stroke is best. Improper placement of the tag in a non-target area or tagging to low can cause injury to the fish. Ideally the target area is the middle shoulder, well above the lateral line and away from the head, gills, gill plates, and other vital organs. After tagging is complete the fish should be released by removing the hook, or by cutting the leader as close to the hook as possible. Frequently, an exhausted fish can be revived by slowly towing the fish through the water prior to release.

tagged black marlinWhen we tag a fish, a return card with release information is sent to the African Billfish Foundation {ABF} including the species, date, location, estimated length and weight, condition, bait, and the angler and captain's identities. The same information is collected when a fish is recaptured.

Surprisingly, this meager list of data can form the basis for many interesting and valuable conclusions. Comparing the location, where the fish was released with where it was recaptured establishes the fish's range, or area where it lives, is catch able, and should be managed.

Looking at the dates the fish was caught and recaptured tells us where the fish are during a given season, which helps establish their migratory pattern, or path they take in their travels. This seasonality helps us determine whether we may be counting the same fish several times, just in different areas.

The estimated lengths and weights, when compared over the time between tag and recapture, help scientists determine how fast fish grow, and also give the only practical estimate of age at a certain size and how long these fish might live- essential ingredients for management.

 The condition recorded on the tag card gives us an insight into how well a fish recovers from being hooked, tagged and released- and encourages us to release fish even if we think they may be damaged. Many times taggers have thought just that, and recorded ''bad condition'' on the card, only to have the fish recaptured, alive and well, years later.

Tagging a billfish is easier said than done at times. Just as this crewman was about to tag this small blue marlin it burst away  with a sudden explosion of energy,  leaving the tag placement far back but safely above the lateral line (as seen below).


*WARNING* Simple control of distribution at the skipper/boat owner level will nip this expensive and growing problem in the bud!

Please could all skippers/boat owners be aware of a scam where unprotected tags stored on board are stolen, the tag card is disposed of and the tag handed in to the ABF as a recovery for the five dollars reward. These are normally pretty obvious to spot as with one case of a boat who had hardly ever even caught a billfish, yet suddenly had many recovered in a short period of time with all the numbers being sequential. On busier commercial boats it is much harder to spot, but becomes more obvious at the end of the season when they produce their figures and tag more than they claim to catch.

We can simply remove all dubious reported recoveries from our data base, but it costs the ABF the production and transport of the tags, the five US dollar reward per tag (we have no choice but to pay up, random refusal to pay rewards for tag recoveries could severely damage the ABF's local networks and recovery systems).


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