Fish Spawning Aggregations: an illusion of plenty

Spawning aggregations are a behavior shared by many species across the globe, often including 95% of the population of one single fish. Grunts in a mangrove forest, Baja California, Mexico.

This article is brought to you by the International League of Conservation Photographers (iLCP). Read our other articles on the National Geographic Voices blog featuring the work of our iLCP Fellow Photographers all around the world.

Text by iLCP Fellow Jaime Rojo, and photos by iLCP Fellow Octavio Aburto, as part of their Natural Numbers initiative.

Spawning aggregations are a behavior shared by many species across the globe, often including 95% of the population of one single fish.
Grunts in a mangrove forest, Baja California, Mexico.

Spawning aggregations are massive gatherings of fish for breeding, a behavior shared by many species across the globe in many different habitats. They are predictable because they usually happen at the same place and at the same time each year, and humans have taken advantage of this to harvest large numbers of fish with minimal effort. Spawning aggregations support some of the most productive fisheries: from multibillion-dollar industries to subsistence cultures, but according to Brad Erisman, Professor of Marine Science from the University of Austin at Texas “management attention for spawning aggregations is not equivalent to their importance. Despite their contribution to global fisheries production, ecosystem health, and food security, few aggregations are managed and protected in the right way. Among those that have been studied, more than half are declining and roughly 10% have disappeared. Fortunately, there is growing evidence that when aggregations are managed and/or protected, they can recover to benefit both fisheries and ecosystems.”

In the upper Gulf of California, in Mexico, a large marine fish known as Gulf Corvina offers an insight into the importance of this behavior. During a single fishing season, up to 2 million corvinas can be caught in just 25 days of labor
A truckload of corvinas in Santa Clara, Upper Gulf —> Read More

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