Climate, ecology and productivity of Pacific sardine (Sardinops sagax) and hake (Merlucciusproductus)


Agostini, V.N. 2005. Climate, ecology and productivity of Pacific sardine (Sardinops sagax) and hake (Merlucciusproductus). Ph.D. dissertation, School of Aquatic and Fishery Sciences, University of Washington, Seattle.


The volatility of pelagic fisheries in the California Current (CC) system has long been a challenge for the west coast fishing community. Over the last century, a number of west coast pelagic stocks have undergone large fluctuations in abundance. Faced with sudden collapses in once thriving fisheries (e.g. Pacific sardine in the late 1940s and Pacific hake in the 1990s), resource managers have struggled to understand the causes behind these fluctuations and develop appropriate responses. The overarching objective of this dissertation is to understand how climate, through its effects on pelagic habitat, influences production variability of sardine and hake in the CC system. I show that climate forcing of the CC system results in dynamic distributions of Pacific sardine and hake populations. I find pelagic habitat for these species to be dynamic, its boundaries changing according to time/space changes of the physical oceanographic variables defining it. By considering the oceanography of pelagic habitats I reveal important links between atmosphere-ocean variability and fishery productivity. A more complete understanding of these links could provide us with tools to better manage the fisheries. The focus of this study on two ecologically and commercially important species will allow for a better understanding of ecosystem variability as a whole, an understanding that will be relevant within the context of the current management structure.