North Pacific Anadromous Fish Commission

Technical Report 23

Table of Contents

Post-smolt Sockeye Stock Ratios and Adult Stock Ratios: Similar Survivability Between the Two Life History Periods?

Authors:
Angela Phung, Stephen Latham, and Catherine Michielsens

Abstract Excerpt:
Fraser River sockeye salmon vary greatly in return strength, year-to-year, in part due to highly variable post-smolt survival (McKinnell et al. 2014). Difficulties in understanding and predicting marine survival, as well as increasing climate volatility, have made pre-season forecasts of returns particularly challenging in recent years.  Compared to pre-season forecast models, using smolt data in run size assessments early in the season should reduce the impact of climate variability on predictions of adult returns, as two years of climate impacts are integrated in smolt life history. Having a better understanding of survival during early sockeye life history will facilitate how to best use post-smolt data in management. Historical post-smolt data collected from various programs in the last two decades at various locations during their out-migration may answer: (1) Are there differential impacts on post-smolt survival among stocks during their initial few months? (2) Are there differential impacts on post-smolt survival among stocks after their initial few months? (3) Can post-smolt stock ratios be applied to predict adult ratios in management?

*This is the first paragraph of an extended abstract. Download the full abstract below.

DOI:
https://doi.org/10.23849/npafctr23/b55-dk8

Citation

Phung, A., S. Latham, and C. Michielsens.  2024.  Post-smolt sockeye stock ratios and adult stock ratios: similar survivability between the two Life history periods?  N. Pac. Anadr. Fish Comm. Tech. Rep. 23: 64–67.  https://doi.org/10.23849/npafctr23/b55-dk8