美国科学60秒 SSS 2015-05-13（在线收听）

 Crop rotation is a recognized way to keep soil and food eco-system healthy. Now scientists are saying that rotation could be a useful tool in the sea. Researchers tracked the shallow water near shore species used for food-sea cucumbers. They'are easy to harvest and are fairly valuable. But the same attributes mean they are easy to overharvest. The parctice has put some sea cucumber species at high risk of extinction, even in a relatively well-managed area, the Great Barrier marine part in Australia. In 2004, authorities split the Great Barrier Reef into 154 zones where each zone was fished only once every 3 years. Fishers rotate through the region. In computer models, the researchers ran through dozens of simulations of each zone both before and after the division took place. The trials revealed that even with an identical and low capture allowance in all cases, the sea cucumbers would recover more foily under rotation strategy than by harvesting simultaneously throughout the region. In fact in trails that included rotations, the yield actually increased. The research is in the proceding of the national academic Of Sciences. The scientists say their results suggest that such rotation might be beneficial in these kinds of shallow marion regions around the world, particularly for species that are in high demand. Because you should not eat your seed corn or your seed sea cucumbers.