North Pacific Anadromous Fish Commission

Technical Report 23

Table of Contents

Salmon, Oceanography, and Heterosigma: Insights from a 23-year Observation in the Strait of Georgia

Authors:
Svetlana Esenkulova, Chrys Neville, Rich Pawlowicz, Vera Pospelova, and Isobel Pearsall

Introduction:
The Strait of Georgia (SoG), Canada, is an important rearing ground for Pacific salmon. In recent decades, many populations of salmon in SoG have experienced dramatic declines (e.g., Beamish et al. 2010; Riddell et al. 2018). Phytoplankton is the foundation of the marine food web; however, the proliferation of some algal species causes severe economic losses to aquaculture and fisheries and has major environmental and human health impacts.  Heterosigma akashiwo is a raphidophyte (a group of algae different from diatoms and dinoflagellates in various structural, ecological, and physiological aspects) and a prominent fish-killer (Hallegraeff et al. 2004). Heterosigma has had devastating effects on BC aquaculture since the 1960s (Taylor and Haigh 1993) and is one of the primary causes of aquacultured salmon mortalities, with estimated annual losses of millions of dollars (e.g., Rensel and Whyte 2004; Haigh and Esenkulova 2014). Blooms of Heterosigma in the SoG were linked to poor wild salmon survival (Rensel et al. 2010), and several indications suggest that wild juvenile salmon in the SoG may be directly affected by algal blooms similarly to farmed salmon (Esenkulova et al. 2022). This study aimed to investigate the relationship between salmon, oceanographic conditions, and the single-cell algae causing harmful algal blooms, Heterosigma akashiwo.

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

DOI:
https://doi.org/10.23849/npafctr23/qm-90-8p6

Citation

Esenkulova, S., C. Neville, R. Pawlowicz, V. Pospelova, and I. Pearsall.  2024.  Salmon, oceanography, and Heterosigma: insights from a 23-year observation in the Strait of Georgia.  N. Pac. Anadr. Fish Comm. Tech. Rep. 23: 27–29.  https://doi.org/10.23849/npafctr23/qm-90-8p6