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Science 3 February 2012: Vol. 335 no. 6068 pp. 520-521 DOI: 10.1126/science.335.6068.520 News Focus Ecology Rebuilding Wetlands by Managing the Muddy Mississippi Carolyn Gramling Coastal managers and scientists have struggled to find ways to restore water flow through the wetlands of the Mississippi delta and bring back the sediment, supply of which has been cut in half by humanmade river channels, levees, and dams intended to control the river and save coastal communities from flooding. The U.S. Army Corps of Engineers opened the Morganza spillway during the 2011 Mississippi River floods to divert floodwaters, which offered a rare opportunity to conduct a large-scale natural experiment in real time. The floodwaters did carry enough sediment to help rebuild the wetlands, but that material didn't always stay where it could do the most good. However, researchers gained valuable insights-including ideas about how spillway design can help produce more targeted sediment deposits, and what volume of flow through the spillways might be required for effective wetland rebuilding.

Right Whales Finally Coming Home Figure "CREDIT: MICHAËL CATANZARITI/WIKIMEDIA COMMONS" After more than 100 years, right whales have returned to their calving grounds in New Zealand, an international team of scientists reports. The 100-ton whales, known for their social frolicking and impressive acrobatic displays, were hunted to extinction in these same waters during the 19th and 20th centuries' era of industrial whaling. A small population managed to survive near remote, sub-Antarctic islands south of New Zealand. In recent years, a few dozen females found their way back to the same bays their ancestors used for bearing their young. Normally, such cultural knowledge is passed from mother to daughter, the researchers say. But the tradition had been lost, until these pioneering females began making the journey once again. Reporting in Marine Ecology Progress Series, the scientists-from Canada, the United States, Australia, and New Zealand-confirmed that some of the females had migrated from the southern islands to New Zealand by comparing the DNA in tissue samples collected from seven whales at both sites. Now that the tradition has been restored, scientists expect more whales to follow the pioneers.