Federal biologists are deciding what parts of Cook Inlet are vital to the survival of the area's population of beluga whales, and want to know what you know about the animals.The National Marine Fisheries Service listed the belugas as an endangered species last October. Now scientists have to designate "critical habitat" for the whales. Once that happens, federal agencies will have to make sure they don't fund activities or projects in those habitat areas that further endanger the whales.NMFS is asking for help in answering several questions, including: • What parts of the inlet are used by belugas, and when? • What physical and biological features of the inlet are essential to the whales' survival? • What kinds of protection are important for those areas?• What are the economic trade-offs? Are some areas so important for other reasons that they should not be designated as "critical habitat?"• What current or planned activities or projects in Cook Inlet might affect the whales' habitat?"We aren't yet proposing a rule on critical habitat for the Cook Inlet beluga whales, but we will," said Doug Mecum, acting Alaska administrator for NMFS, in a written statement. "This notice is an effort to get as much information as possible early in the process."Comments and information will be accepted until May 14. Studies have shown Cook Inlet's belugas are a genetically distinct species and don't interact with belugas in other parts of the North Pacific. A 1979 survey put the population at about 1,300 animals, but during the 1990s their numbers plummeted and a survey in 1998 estimated about 350 whales remained in the inlet. Subsistence hunting of the whales was largely curtailed, and scientists hoped their numbers would recover. That has not happened. The population now is believed to be 300 to 400 animals.Comments and information about the Cook Inlet belugas can be sent to the Protected Resources Division, NMFS, P.O. Box 21668, Juneau 99802-1668.