Tag Recovery

So you've caught a tagged halibut...

and you've decided to collect the data yourself. There are a few of things we'd like you to do:

1. Remove the tag from the fish.

Please note that, starting September 2003, we will be conducting a special double-tagging experiment in B.C. waters. A selection of fish will be tagged with an external, spaghetti wire tag through the dark-side cheek, along with an internal Passive Integrated Transponder (PIT) tag. If you find a two-tone orange tagged fish, please do not remove the tag from the cheek. If possible, contact the local IPHC Port Sampler or contact the Seattle office at (206) 634-1838. For further details on this project, please see our News Release.

Over the years, the Commission has used several types of tags. The most common is the spaghetti wire tag which is looped through the darkside cheek. To remove this tag, the wire can be untwisted and pulled through the hole, or it can be cut from the cheek. Please try not to cut the tag (or yourself). The other tag types used were metal or plastic-tipped dart tags. Dart tags must be cut from the fish. Please make sure that the tag is completely removed from the flesh to avoid any gastronomic mishaps. The metal-tipped tags were placed in the cheek while the plastic-tipped ones were inserted behind the fin rays above the head.

Don't lose the tag--it's the proof you'll need to get your reward.

2. Measure the fork length of the fish

Measure the length of the fish (preferably in centimeters) from the tip of its mouth (chin) to the fork of its tail. The proper measurement is a flat, horizontal distance rather than a measurement which follows the contour of the fish. Please make certain the fish is on a flat surface and that the mouth is closed.

The best way to make a measurement is to:

Place the fish's chin against a stable vertical surface, such as a wall

Put a marker at the fork of the tail

Remove the fish

Measure the distance from where the fish touched the vertical surface to the marker.

3. Cut out the otolith*

The otoliths, or earbones, are used to determine the age of the fish. There are 3 pairs of otoliths in each fish, though only 1 pair is easily visible. Of this visible pair, we want the one from the white side.

If the fish is round (gills and guts intact) the first thing to do is remove the gills. Make note of where the top part of the gills connects to the backbone: this is where you'll find the otoliths.
Lay the fish white side up and lift open the operculum, or gill cover. Run your finger along the backbone near where the gills used to be. You should feel a bulge. This is the otic capsule.
Using a moderately sharp knife, make a shallow cut and take the top off the capsule. If done right, you should see a cavity with the otolith suspended within.
Place the otolith in a protective container so that it is not crushed.

[Diagram 83K]

* Please don't attempt this if you're not good with knives. Minors (who are old enough to play with knives) should still have adult supervision. The Commission takes no responsibility for any possible injuries resulting from this procedure.

4. Submit the information

In addition to the otolith and fork length, we would like:

Tag number: if the number appears illegible, don't throw the tag away. We can still read it in the lab.

Recovery date: when the fish was caught

Location: preferably latitude/longitude coordinates, though distance and bearing from a landmark would be acceptable (e.g.. 3 miles SW of Cape Barto)

Depth: the depth at which you were fishing, in fathoms (1 fathom = 6 ft)

Sex: male or female, if known

Gear type: longline, troll, trawl, pot, or sport

Landing port: where the fish was brought in

Vessel name and number: if commercially caught

Name and complete mailing address

Reward type: baseball cap or $5.00

If more than one tag is recovered, please keep the information from each fish separate.

Return this information to:

IPHC
Attn: Joan Forsberg
PO Box 95009
Seattle WA 98145-2009
USA

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