LOXAHATCHEE NATIONAL WILDLIFE REFUGE — Four large constrictor snakes will be illegal to import or move across state lines, the federal government said Friday, while stopping short of including the popular boa constrictor among the banned. Completing a process years in the making, the U.S. Fish and Wildlife Service announced the "injurious wildlife" status of three species of anacondas and one type of python it fears could one day take hold in the Everglades, where giant non-native snakes have overwhelmed the ecosystem, killing and swallowing whole animals as large as deer and alligators. It piggybacks on similar action three years ago for four other types of big snakes. "We're taking that preventative step to keep another ecological disaster from happening," said Dan Ash, director of the wildlife service. The move does not prohibit those who already have snakes from keeping them, and intrastate sales remain legal wherever they were allowed before. It is meant to stem further growth of the population of certain snakes whose owners might later release them into the wild. Such illegal release is blamed, in large part, for the growth of the population of Burmese pythons in the Everglades. The federal government initially proposed such action on nine snakes in 2010. Two years later, it finalized the status for Burmese pythons, yellow anacondas and northern and southern African pythons, all of which have been found in the wild. The four species added Friday were the reticulated python and green anaconda, both of which have been found in small numbers in the wild in Florida, as well as the DeSchauensee's anaconda and Beni anaconda, which have not yet spread. "We want to keep all of these species out," Ash said. The only species initially proposed for the list that was not included was the boa constrictor. Ash said that species' widespread distribution across the U.S. was the biggest factor in deciding not to list it with the other snakes, but he also made note of the "potential adverse economic effects of the industry," a signal the passionate pleas of reptile traders was heard to some degree. Still, some were unhappy with the move, including Matt Edmonds, a snake collector and dealer from West Palm Beach, who buried his head in his hands as Ash spoke and wiped tears from his eyes. He insisted the move could drive him and other snake breeders to homelessness and that such rules should be addressed on a state-by-state basis to avoid penalizing people in places where the snakes can't even survive in the wild. "We can no longer put food on our tables," Edmonds said, while professing his affection for creatures he says are inherently gentle. "This is not just financial. This is the love and the passion for these animals." Edmonds confronted Ash after the announcement but got nowhere. Ash noted the government had provided a 210-day public comment period leading to the decision. The rules will take effect 30 days after being entered in the federal register.