What Influences Fisheries Production? Comparing the Effects of Environmental, Fishing, and Food Web Forcing Across Large Marine Ecosystems

With growing interest in taking an ecosystem approach to fisheries management, it is increasingly important to understand the complex forces regulating ecosystem dynamics. In particular, how do climate forcing and food web structure interact to support fisheries production, and what processes amplify, dampen or obstruct the production that ecosystems provide? We present the results of an international workshop focused on applying multiple surplus production models to widely diverse ecosystems of the world’s oceans to understand how multiple drivers of productivity in fishery ecosystems simultaneously interact to determine overall production levels. These drivers reflect a triad of factors influencing fisheries production including fisheries, the environment, and trophodynamics. The presentations will describe a common methodological framework (i.e. surplus production models) that is applied across several levels of taxonomic aggregation, for several species, and communities from several marine ecosystems and examine model outputs from multiple production modeling packages. They also estimate management-relevant metrics and ecosystem attributes and compare them across populations and ecosystems, and describe the utility of applying surplus production models in single-species, multi-species, and aggregate species group frameworks. The results particularly elucidate those links between the biogeochemistry, ecology, and harvesting in these ecosystems that are globally consistent. They also highlight some challenges of fitting such production modeling approaches to similar species or functional guilds in contrasting arrangements (different species within ecosystems and similar species between ecosystems) to better delineate what controls ecosystem fisheries productivity. Implications of these results for future work relevant to operational oceanography, population and community modeling, and ecosystem-based fisheries management will be discussed.