Modelling the sequential geographical exploitation and potential collapse of marine fisheries through economic globalization, climate change and management alternatives

Abstract

SUMMARY: Global marine fisheries production has reached a maximum and may even be declining. Underlying this trend is a well-understood sequence of development, overexploitation, depletion and in some instances collapse of individual fish stocks, a pattern that can sequentially link geographically distant populations. Ineffective governance, economic considerations and climate impacts are often responsible for this sequence, although the relative contribution of each factor is contentious. In this paper we use a global bioeconomic model to explore the synergistic effects of climate variability, economic pressures and management measures in causing or avoiding this sequence. The model shows how a combination of climate-induced variability in the underlying fish population production, particular patterns of demand for fish products and inadequate management is capable of driving the world's fisheries into development, overexploitation, collapse and recovery phases consistent with observations. Furthermore, it demonstrates how a sequential pattern of overexploitation can emerge as an endogenous property of the interaction between regional environmental fluctuations and a globalized trade system. This situation is avoidable through adaptive management measures that ensure the sustainability of regional production systems in the face of increasing global environmental change and markets. It is concluded that global management measures are needed to ensure that global food supply from marine products is optimized while protecting long-term ecosystem services across the world's oceans.Keywords: fisheries modelling, sequential exploitation, economic globalization, climate change, fisheries management. RESUMEN: Modelización de la explotación sucesiva y posible colapso de las pesquerías marinas por medio de la globalización económica, cambio climático y alternativas de gestión. -La producción pesquera mundial ha superado su máximo potencial y parece estar en declive. Esta tendencia es el resultado de una sucesión de desarrollo, sobreexplotación, agotamiento, y en algunos casos, colapso de los stocks pesqueros individuales. Este proceso conecta recursos distantes a nivel geográfico. Esta secuencia es a menudo atribuida al efecto combinado de una gestión deficiente, consideraciones económicas y efectos ambientales pero la influencia de cada uno de estos factores suele ser difícil de determinar. En el presente trabajo hemos utilizado un modelo bioeconómico global para explorar los efectos conjuntos de la variabilidad climática, presiones económicas y medidas de gestión para producir o evitar esta secuencia. El modelo muestra como una combinación de variabilidad de origen climático en los stocks, el aumento de la demanda de productos marinos y una gestión deficiente es capaz de dirigir las pesquerías mundiales a través de un proceso de desarrollo, sobreexplotación, colapso y recuperación similar a los patrones observados. Además, mostramos cómo el patrón secuencial de sobreexplotación puede emerger como una propiedad endógena...

Can marine fisheries and aquaculture meet fish demand from a growing human population in a changing climate?

“…The consequence of this is that strict fisheries management and market stabilization measures will be crucial to ensure the sustainability of fisheries dedicated to fishmeal and oil production. Thus management systems need to be sufficiently robust to control fishing mortality despite increasing demand (Berkes et al, 2006;Merino et al, 2011;O'Brien and Leichenko, 2000). While some recent management efforts have led to improved controls of fishing mortality, along with stock stabilization and recovery in some places (Branch et al, 2011;Worm et al, 2009), some small pelagic fisheries continue to be sub-optimally managed and sensitive to demand changes (Asche and Tveterå s, 2004).…”

Projected Economic Impact of Climate Change on Marine Capture Fisheries in the Philippines

“…It was found that coastal low-income food deficit countries (LIFDC) are heavily dependent on fish catches as a way of meeting their nutritional needs but almost every coastal LIFDC is in danger of decrease in fisheries maximum revenue potential. Merino et al (2011) examined the synergistic effect of climate variability and production of fish with estimation of maximum sustainable yield. They put emphasis on global management measures to achieve optimized global supply of marine products, suggesting interaction between global markets and regional climate may be acting as a factor causing sequential overexploitations and resource depletion.…”

Using global catch data for inferences on the world’s marine fisheries

“…For example, if stock biomass declines because of climate shifts, catches will also eventually decline and this scenario will also be interpreted as overfishing and collapse in the SSP (e.g. Peruvian anchoveta, Engraulis ringens, Engraulidae, Bakun and Weeks 2008;Arias-Screiber et al 2010;Merino et al 2011). A good number of fisheries in coastal regions (mainly in developed countries) progressed to tighter regulations to either prevent collapse or in response to a significant decline in landings, usually attributable to heavy exploitation.…”

“…Peruvian anchoveta, Engraulis ringens , Engraulidae, Bakun and Weeks 2008; Arias‐Screiber et al. 2010; Merino et al. 2011).…”