Method name: Individually tagging of salmon with microtags.
Key-words: Atlantic salmon, tagging, CWT, coded wire tag, individually microtagged smolt, survival, growth.
Institute: Institute of Freshwater Fisheries, Reykjavík, Iceland.
Contact (Author): Thorolfur Antonsson
Species tagged: Atlantic salmon (Salmo salar)
Stock assessment (x)
Research of return rate and growth in sea phase of salmon and connection with environmental factors.
What kind of smolt-properties are most successful in the sea (large, small, fat, thin etc.)
Materials and equipment:
Tag type: Microtag and adipose fin clipping (for identification of microtags)
Desciption of method:
The microtags wire have a serial code and by taking one tag between each tagged fish makes it possible to find this particular fish again in your database. When tagging, the adipose fin is cut of, length and weight of the fish are measure and are written in a database (or blank-form) and then we inject the wire tag. Next, one wire tag is taken on a cotton pin (so we donít damage the needle of the injector) and taped on the blank-form behind the information about the fish.
In case of salmon smolts they are caught in traps when migrating down the river. Then anesthetized and tagged. After recovering in fresh water for 15-20 minutes we release it again. When the salmon have dwelled in the sea for one or two years it migrate back to its home river and then it is possible either examine each fish in a trap or examine each fish in the salmon catch. If there is a lack of adipose fin, we take the part of the head where the wire tag was injected and take out the tag. And because each tag have its own number (as a part of the serial code) then you search for the tags before and after this special tag and find the information about this particular fish. The fish is individually tagged.
Tagging efficiency is two or three times less when individually tagging comparing to group tagging with microtags.
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Parker, A.E. Giorgi, R.C. Heidinger, D.B. Jester, E.D. Prince og G.A. Winans
(ritstj.). American Fisheries Society Symposium 7:782-816. Bethesda, Maryland.
Sumarliði Óskarsson og Árni Ísaksson 1988. Merkingar. Bls. 264-273. Í: Hafbeit,
ráðstefna í Reykjavík, Valdimar Gunnarsson (ritstj.). Útgefið af Veiðimálastofnun.