Northwest Fisheries Science Center

Display All Information

Document Type: Contract Report
Center: NWFSC
Document ID: 9071
Title: Monitoring the migrations of wild Snake River spring/summer Chinook salmon juveniles, 2015-2016
Author/Editor: Jesse J. Lamb, Benjamin P. Sandford, Gordon A. Axel, Steven G. Smith, Matthew G. Nesbit, Beth L. Sanderson
Publication Year: 2017
Publisher: National Marine Fisheries Service
Contracting Agency: Bonneville Power Administration. Portland, Oregon

During July-August 2015, we PIT tagged 16,148 wild Chinook salmon parr and released them to 16 Idaho streams or sample reaches.

Overall observed mortality from collection, handling, tagging, and after a 24-h holding period was 1.4%.

During 2016, we recaptured 784 of these fish using the separation-by-code system at Lower Granite Dam.  Recaptures included fish from all 16 Idaho populations.

For the 784 recaptured fish, average growth was 35 mm in length and 8.0 g in weight over an average period of 261 d.  Mean condition factor declined from 1.15 at release (parr) to 1.03 at recapture (smolt).  Among fish tagged and released as parr in 2015, mean length at release was significantly greater for fish detected during spring and summer 2016 that for those that were never detected (P < 0.0001).

For tagged parr from all 16 Idaho populations, peak detections at Lower Granite Dam occurred during 13-15 April 2016.  Respective dates of the 10th, 50th, and 90th passage percentiles were 13 and 23 April and 11 May 2016.

For fish from all Idaho streams combined, the average estimated rate of survival to Lower Granite Dam (parr-to-smolt survival) was 10.4% (range 2.85-18.36%).


Notes: Project 1991 028 00, Contract No. 46273 REL 62 Contract CR 291473 Covering the period from mid July 2015 to mid July 2016
Theme: Recovery and rebuilding of marine and coastal species
Foci: Characterize the population biology of species, and develop and improve methods for predicting the status of populations.