New study looks at how shocks like political change, natural disasters, diseases and overfishing have affected capture fisheries and aquaculture worldwide


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New study looks at how shocks like political change, natural disasters, diseases and overfishing have affected capture fisheries and aquaculture worldwide

Looking back on these events has value in both understanding and learning about what to do in the event of a shock. While many cases have been studied in detail, few analyses have taken a more generalized, data-driven approach to detect and understand why shocks on the food system have occurred. Even fewer quantitative studies have attempted to understand shocks to fisheries production around the world.

But in a recent paper published in Global Environmental Change a team of researchers, including GEDB and Beijer Institute researcher Max Troell, apply a data-driven approach to understanding global fisheries and shocks they endured between 1976-2011.

Differences across the globe

To examine shocks that occurred in global fisheries, Troell and colleagues look at seafood production in 127 countries between 1976-2011, using FAO statistics. They characterize seafood production in two different systems, aquaculture and capture fisheries, and look at different types of shocks such as political, natural disaster, diseases, overfishing, etc.

In the 35-year time period, the analysis yields a total 48 seafood production shocks worldwide. The study finds that the rate of shocks to seafood production systems was highest in the Caribbean and Central America, followed by Africa, Asia, and Europe, respectively. In other words, Caribbean and Central America experience shocks more often than the other regions.

While the Caribbean, Central America, and Africa experience the most shocks, they also tend to recover the fastest, whereas a seafood production shock in Asia or Europe tends to be bigger. Political factors also tend to be the most common trigger for seafood production shocks.

Lead author Jessica Gephart at University of Virginia, elaborates, “In general, the distributions of magnitudes and recovery times are asymmetric, such that most shocks are small and most recoveries are quick, but when they are not the largest shocks are much larger or longer than the medians.”

When comparing seafood production shocks to capture or aquaculture fisheries, the study finds that they both experience the same magnitude and recovery time when it comes to production shocks, but aquaculture shock rates are higher from 1980 onwards.

“While the cause of this difference is unknown, aquaculture is vulnerable to shocks from disease outbreaks and possibly also from rapid growth over-shooting environmental carrying capacity,” explains Max Troell.

The study also detect three different coping mechanisms used by affected countries, and analyse when the different mechanisms are used.

Learning from history

Understanding sustainable fishery production levels help to define sustainable fishing quotas, and in turn avoid stressing the system into a seafood production shock.

Overfishing, political changes, and many other shocks have repeated themselves in history, and there is value in generalizing and learning from past mistakes.

As Geparth concludes, “The capacity of countries and communities to respond and adapt to shocks to seafood production speaks to their resilience. Learning from historical examples of shock causes, impacts, and responses provide opportunities to build resilience.”

Gephart, J. A., L. Deutsch, M. L. Pace, M. Troell, and D. A. Seekell. 2017. Shocks to fish production: Identification, trends, and consequences. Global Environmental Change 42:24–32