Premium
Management Briefs: Field Evaluation of Visible Implant Tag Retention by Brook Trout, Cutthroat Trout, Rainbow Trout, and Arctic Grayling
Author(s) -
McMahon Thomas E.,
Dalbey Steven R.,
Ireland Susan C.,
Magee James P.,
Byorth Patrick A.
Publication year - 1996
Publication title -
north american journal of fisheries management
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.587
H-Index - 72
eISSN - 1548-8675
pISSN - 0275-5947
DOI - 10.1577/1548-8675(1996)016<0921:mbfeov>2.3.co;2
Subject(s) - rainbow trout , trout , grayling , fishery , salvelinus , arctic , biology , fish <actinopterygii> , ecology
We assessed retention of visible implant (VI) tags by salmonids under field conditions. Tag retention by wild cutthroat trout Oncorhynchus clarki ( N = 413) from a headwater stream declined over time, from 87% at 1–60 d after tagging to 54% at 61–165 d and 50% at 270–430 d. Tag retention rates by rainbow trout O. mykiss captured by electroshocking from a river and transported to a small pond were 54% at 100 d ( N = 115) and 51% at 335 d ( N = 419). Hatchery‐origin Arctic grayling Thymallus arcticus and wild brook trout Salvelinus fontinalis held in enclosed stream sections had respective tag retention rates of 98% ( N = 187) and 59% ( N = 63) at 30 d. Among all species, most fish 130–160 mm in length shed the VI tag. Brook trout over 170 mm total length and cutthroat trout over 200 mm fork length (FL) had significantly greater ( P < 0.05) tag retention than smaller fish. However, for rainbow trout 153–388 mm FL, there was no relation ( P > 0.18) between fork length and tag retention in the two length‐groups (<200 mm and >200 mm at tagging). Because tag retention may approach only 50% for some salmonids, we recommend placing another batch mark or tag on VI‐tagged fish to retain information on fish that lose VI tags.