With more than 900 manatee deaths this year in Florida, conservation groups signaled that they plan to file a lawsuit against the federal government over "critical habitat" areas for the sea cows.

The Center for Biological Diversity, Defenders of Wildlife and the Save the Manatee Club filed a notice of intent to sue the U.S. Fish and Wildlife Service, alleging that it has violated federal law by not updating designated critical-habitat areas to better protect manatees.