Dynamics of the Fraser River plume front: implications for fish larval survival

点击翻译按钮获取中文摘要

The understanding of factors leading to fluctuations in fish populations, including salmonids, remains an important challenge in fisheries research. The feeding during the initial oceanic period is crucial for the recruitment success of fish. The juvenile oceanic survival may therefore be enhanced in coastal regions reach with short-living and very dynamic (ephemeral) frontal features. This is because near-coastal fronts, including plume, tidal and shelf-break fronts, appeared to have higher productivity and longer retention time compared to adjacent waters. The ephemeral nature of these fronts is often not reflected in enhanced planktonic stocks, which create difficulties in detection of their biological importance by traditional field techniques. Biological rate processes, rather than plankton stocks, appeared to be enhanced in such frontal features. The overall goal of the proposed research is to better understand the underlying factors contributing to fluctuations in fish populations and recruitment. Specifically, this research will investigate interactions between small-scale physical disturbances and larval fish biology and demography. This will be addressed using a novel methodological approach by combining a compound stable isotope composition of cellular biomolecules with standard techniques currently used in the field of biological oceanography. This research will provide a fundamental knowledge of the significance of small-scale oceanic processes and planktonic hot spots in the overall ecosystem budget. It is anticipated that the findings of this study could be used to improve management of fish stocks and juvenile fish survival by incorporating the above knowledge into fish population modeling.