New Zealand Journal of Marine and Freshwater Research abstracts

---

A test of the reliability of otolith and scale readings of Chinook salmon (Oncorhynchus tshawytscha)

MALCOLM FLAIN GORDON J. GLOVA

Freshwater Fisheries Centre Ministry of Agriculture and Fisheries P.O. Box 8324, Riccarton Christchurch, New Zealand

Abstract The reliability of otolith and scale readings of RakaiaRiver chinook salmon, Oncorhynchus tshawytscha, were tested. One experienced reader aged samples of 405 and 508 adult fish of known age, from otoliths and scales, virtually 100% correctly, Ages estimated from scales from 402 adult fish of unknown age, read in triplicate, were in complete agreement 92.5% of the time. The freshwater life history type was consistently identified for 90.6% of the fish on the basis of pattern of scale circuli in the first year's growth. A comparison of these results with those in the literature indicates that fish aging by one experienced reader was more precise and more accurate than by combined efforts of several readers.

Keywords aging; RakaiaRiver; coded-wire tags; Chinook salmon; Oncorhynchus tshawytscha; otoliths; scales; accuracy; precision

New Zealand Journal of Marine and Freshwater Research, 1988, Vol. 22: 497-500 Crown copyright 1988Received 14 September 1987; accepted 16 December 1987

PDF file of entire paper: medium quality (1298K); (scanned from paper original: notes about this process)

---

This year's abstracts | Journal home page | All abstracts | Publishing home page