Crop rotation is a recognized way to keep soil and the food ecosystem healthy. Now, scientists are saying that rotation could be a useful tool—in the sea. Researchers tracked a shallow-water, near-shore species used for food: sea cucumbers. They're easy to harvest and are fairly valuable. But those same attributes mean they're easy to overharvest. The practice has put some sea cucumber species at high risk of extinction, even in a relatively well-managed area, the Great Barrier Marine Park in Australia. In 2004 authorities split the Great Barrier Reef into 1 54 zones, where each zone was fished only once every three years. Fishers rotate through the region. In computer models, the researchers ran through dozens of simulations of each zone, both before and after the divisions took place. The trials revealed that even with an identical and low-catch allowance in all cases, the sea cucumbers would recover more fully under the rotation strategy.