Fish are implanted with tiny wire tags that would distinguish them from wild specimens that scientists hope to capture in surveys.
To address this problem, we used a pair-wise design based on coded wire tagging data to compare the marine distributions of stream- and ocean-type Chinook salmon from a suite of rivers producing both forms.
Finally, the smolt-to-adult survival of coho in relation to release timing was assessed through coded-wire tag (CWT) data from the Quinsam River.
A small percentage of hatchery-origin fish, with or without an adipose clip, were coded-wire tagged.
From 2006 to 2008, releases of coho from the Quinsam Hatchery were tagged with coded-wire tags (n = 266,692) according to methods described in [19].
Acoustic tags (n = 140) and coded-wire tags (n = 266,692) were implanted into coho salmon smolts at the Seymour and Quinsam Rivers, in British Columbia, Canada.
However, coded-wire tagging of smolts released from the Spius Creek Hatchery provided estimated smolt-to-adult survival rates (Doug Turvey, Spius Creek Hatchery, Fisheries and Oceans Canada, Merritt, BC, Canada, pers. comm).
This hypothesis was tested by correlating local plankton productivity at the time of the smolt release with the smolt-to-adult survival of hatchery-reared coho salmon i.e. return rates were compared between groups of coded-wire tagged smolts released during varied levels of marine productivity.
As a potential result, mark recapture research using coded-wire tags indicates <0.5% of A. nobilis caught in the fisheries are cultured (M. Shane, HSWRI, unpublished data).
