Assessing the relative importance of local and regional processes on the survival of a threatened salmon population

Jessica A. Miller, David J. Teel, William T. Peterson, Antonio M. Baptista

    Research output: Contribution to journalArticlepeer-review

    28 Scopus citations

    Abstract

    Research on regulatory mechanisms in biological populations often focuses on environmental covariates. An integrated approach that combines environmental indices with organismal-level information can provide additional insight on regulatory mechanisms. Survival of spring/summer Snake River Chinook salmon (Oncorhynchus tshawytscha) is consistently low whereas some adjacent populations with similar life histories experience greater survival. It is not known if populations with differential survival respond similarly during early marine residence, a critical period in the life history. Ocean collections, genetic stock identification, and otolith analyses were combined to evaluate the growth-mortality and matchmismatch hypotheses during early marine residence of spring/summer Snake River Chinook salmon. Interannual variation in juvenile attributes, including size at marine entry and marine growth rate, was compared with estimates of survival and physical and biological metrics. Multiple linear regression and multi-model inference were used to evaluate the relative importance of biological and physical metrics in explaining interannual variation in survival. There was relatively weak support for the match-mismatch hypothesis and stronger evidence for the growth-mortality hypothesis. Marine growth and size at capture were strongly, positively related to survival, a finding similar to spring Chinook salmon from the Mid-Upper Columbia River. In hindcast models, basin-scale indices (Pacific Decadal Oscillation (PDO) and the North Pacific Gyre Oscillation (NPGO)) and biological indices (juvenile salmon catch-per-unit-effort (CPUE) and a copepod community index (CCI)) accounted for substantial and similar portions of variation in survival for juvenile emigration years 1998-2008 (R2> 0.70). However, in forecast models for emigration years 2009-2011, there was an increasing discrepancy between predictions based on the PDO (50-448% of observed value) compared with those based on the NPGO (68-212%) or biological indices (CPUE and CCI: 83-172%). Overall, the PDO index was remarkably informative in earlier years but other basin-scale and biological indices provided more accurate indications of survival in recent years.

    Original languageEnglish (US)
    Article numbere99814
    JournalPloS one
    Volume9
    Issue number6
    DOIs
    StatePublished - Jun 12 2014

    ASJC Scopus subject areas

    • General Biochemistry, Genetics and Molecular Biology
    • General Agricultural and Biological Sciences
    • General

    Fingerprint

    Dive into the research topics of 'Assessing the relative importance of local and regional processes on the survival of a threatened salmon population'. Together they form a unique fingerprint.

    Cite this