System-level optimal yield: increased value, less risk, improved stability, and better fisheries

Abstract

Abstract:The discipline and practice of fisheries science and management have had an useful, successful, and interesting history. The discipline has developed over the past century and a half into a very reductionist, highly quantitative, socially impactful endeavor. Yet given our collective successes in this field, some notable challenges remain. To address these challenges, many have proposed ecosystem-based fisheries management that takes a more systematic approach to the management of these living marine resources. Here I describe systems theory and associated constructs underlying system dynamics, elucidate how aggregate properties of systems can and have been used, contextualize these aggregate features relative to optimal yield, and note how this approach can produce useful estimates and outcomes for fisheries management. I explore two contrasting examples where this approach has and has not been considered, highlighting the benefits of applying such an approach. I conclude by discussing ways in which we might move forward with a portfolio approach for both the discipline and practice of fisheries science and management.Résumé : La discipline et la pratique des sciences halieutiques et de la gestion des pêches ont une histoire utile, intéressante et couronnée de succès. La discipline est devenue, au cours du dernier siècle et demi, une entreprise très réductionniste, hautement quantitative et à forte incidence sociale. Malgré nos réussites collectives dans ce domaine, des défis notables demeurent. Pour relever ces défis, de nombreuses personnes ont proposé une gestion écosystémique des pêches qui adopte une approche plus systématique de gestion de ces ressources marines vivantes. Je décris la théorie des systèmes et les constructions associées qui sous-tendent la dynamique des systèmes, j'explique comment les propriétés groupées de systèmes peuvent être utilisées et l'ont été, je mets ces éléments groupés dans un contexte de rendement optimal et je souligne comment cette approche peut produire des estimations et des résultats utiles pour la gestion des pêches. J'explore deux exemples dans lesquels cette approche a, d'une part, été prise en considération et, d'autre part, ne l'a pas été, afin de souligner les avantages de son application. Je conclus en discutant d'avenues possibles pour l'avenir qui reposent sur une approche de portefeuille tant pour la discipline que pour la pratique des sciences halieutiques et de la gestion des pêches. [Traduit par la Rédaction]

Ecosystems say good management pays off

“…Ecosystem‐based management, whether focused solely on fisheries or integrated across multiple marine uses, could add a further regulatory and fiscal burden, particularly given its call for a broader system perspective. Evidence is growing that the portfolio approach provided by an ecosystem perspective provides ecological and financial benefits (Link, ). Guidelines (Essington et al., ; NOAA ) have been created to assist in the implementation of ecosystem‐based fisheries management (EBFM).…”

Control mechanisms and ecosystem‐based management of fishery production

“…The good fit of our model to the global dataset of 130 ecosystems over a six‐decade period demonstrates that a broad set of influencing factors together shape fishery production and justifies the suitability and necessity of a holistic approach that focuses on aggregate properties and dynamics of marine ecosystems (Link, ) for management, instead of on specifics at the stock level. However, it should be emphasized that control over fishing or catch at the ecosystem level is much more complex and dynamic than that at the single‐species level and we likely have some way to go before such approaches provide accurate and reliable inputs to defining fishery catches and are widely adopted for generalized management.…”

Catch diversification provides multiple benefits in inland fisheries

“…Monitoring the statuses and trends of individual stocks can increase opportunities to switch among target species (Garcia et al., ; Katsukawa & Matsuda, ). Link () has suggested that the aggregate‐level stock rather than individual stocks should be estimated to manage a diverse portfolio of catch species. Stock‐by‐stock assessment is constrained by logistical and financial considerations.…”