Want Faster Ocean Recovery? Manage Predators and Prey Together, Not Separately

We found that marine conservation typically tackles one species or fishery at a time—protect the cod, restore the sharks, manage the herring. Protect the cod. Restore the sharks. Manage the herring. But research by Jameal Samhouri, Adrian Stier, Shannon Hennessey, Mark Novak, Benjamin Halpern, and Phillip Levin suggests this piecemeal approach may be missing a faster path to recovery.

Using mathematical models of predator-prey dynamics, We compared different management scenarios. They simulated what happens when managers focus on prey species alone, predators alone, or coordinate management of both simultaneously. The results were striking: synchronized management often achieved recovery goals substantially faster.

The mechanism makes intuitive sense once you consider food web dynamics. If you protect prey without managing predators, recovering prey populations can be held in check by predators. If you protect predators without addressing prey depletion, predators may have insufficient food to recover. Managing both together allows the food web to rebuild in a coordinated way, with prey base expansion supporting predator recovery.

"The results were striking: synchronized management often achieved recovery goals substantially faster."

The benefits of synchronized management proved most pronounced when predator-prey interactions were strong. In systems where predators heavily influence prey populations, or where prey availability limits predators, coordinating management across trophic levels delivered the largest gains. In weakly interacting systems, single-species approaches performed nearly as well.

This has practical implications for marine managers facing degraded ecosystems. Rather than restoring one component at a time, comprehensive ecosystem-based management might achieve faster results. This doesn't necessarily mean doing more; it means coordinating existing management actions across species.

The findings also caution against some intuitive management sequences. Managers might assume rebuilding prey first creates a foundation for predator recovery. But the models suggest this staged approach can be slower than simultaneous management. The optimal path depends on food web structure and the strength of species interactions.

Implementing synchronized management faces institutional challenges since different species often fall under different agencies or regulations. But as ecosystems face accelerating threats from climate change, finding faster paths to recovery becomes increasingly urgent.

Citation

Samhouri, Jameal F.; Stier, Adrian C.; Hennessey, Shannon M.; Novak, Mark; Halpern, Benjamin S.; Levin, Phillip S. (2017). Rapid and direct recoveries of predators and prey through synchronized ecosystem management. Nature Ecology & Evolution.

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