Anadromous Salmonids

Anadromous salmonids in the Delta: New Science 2006-2016

Russ Perry, Rebecca Buchanan, Pat Brandes, Jon Burau, Josh Israel

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Key points:

  • The contemporary Delta has been modified to such an extent that salmon populations now contend with an alien environment.
  • Advancements in analysis of otoliths (bones from the inner ear) have been used to provide insights about the role of the Delta in the life cycle of juvenile salmon.
  • Advances in monitoring have improved our understanding of salmonid life histories, but uncertainties in the technology remain.
  • Understanding how juvenile salmonids of different life stages and runs survive in the Delta is critical to devising restoration and management actions.
  • A better understanding of how different life stages use the Delta will help inform management actions to ensure that the Delta is capable of supporting the diversity of life history strategies expressed by salmonid populations.
  • The effects of the recent drought on salmon populations are being evaluated, but will not be fully understood until adults return to spawn; how juvenile salmonids in the Delta have been affected by drought is unknown.