High Incidence of Scale Regeneration by Potamodromous Coastal Cutthroat Trout: Analytical Implications

Autor: Kathleen J. Anderson, Ronald L. Youker, John R. Moring
Rok vydání: 1981
Předmět:
Zdroj: Transactions of the American Fisheries Society. 110:621-626
ISSN: 1548-8659
0002-8487
DOI: 10.1577/1548-8659(1981)110<621:hiosrb>2.0.co;2
Popis: High proportions of the scales from a distinctive stock of coastal cutthroat trout Salmo clarki clarki from the Willamette Valley, Oregon were regenerated. Of 122 fish, from which 50 scales each were taken, 117 (96%) showed more than 50% scale regeneration, and 48 (39%) showed more than 90% regeneration. Age-growth analysis based on 3,521 samples taken from fish in 110 streams in the Willamette drainage was unsuccessful in 0 to 67% of the fish collections because of high regeneration rates. If fish can be sacrificed, otoliths provide age validity equal to or better than that of scales. The other external technique that does not require sacrificing fish—fin ray analysis—is extremely time-consuming and annular rings cannot always be interpreted. For situations where substantial numbers of cutthroat trout cannot be sacrificed, as was the case in most of our studies, we recommend that 50 scales be taken from each fish in order to have 87% confidence that at least three of them will be nonregenerated.
Databáze: OpenAIRE
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