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Spatial dynamics of chinook salmon redds

Posted date: January 23, 2015
Publication Year: 
2014
Authors: Thurow, Russ F.;
Document type: Briefing Papers

Description

Most knowledge regarding the basic ecology of chinook salmon (Oncorhynchus tshawytscha) comes from studies in freshwater environments. Unfortunately, most of this knowledge is derived from studies conducted at relatively small spatial and temporal extents that provide a poor fit to the broader spatiotemporal themes that underlie most species conservation efforts. Growing awareness of this gap, combined with advances in remote sensing, spatial sampling strategies, georeferencing capabilities, and broad usage of GIS have motivated a new generation of studies. It is clear that effective conservation and restoration strategies for chinook salmon and other at-risk fishes will depend on information collected at spatial and temporal scales that match the species’ life history.

Key Findings:

  • Redd numbers increased from 20 to 2271 and the population grew at a rate of 5.3 recruits/spawner.
  • As abundances increased, fish expanded into portions of the stream network previously unoccupied.
  • Distributions were clustered - a limited portion of the network contained the majority of redds.
  • The importance of the highest density spawning areas was greatest when abundances were low, suggesting these areas may serve as refugia during demographic bottlenecks.
  • Spawning distributions were dynamic in space and time, but strongly affected by local habitats and broad climatic controls.