Ruth Hanessian of the Maryland Association of Pet Industries argued against the state's proposed ban on snakeheads by comparing the fish to puppies [Metro, July 8]. Although both snakeheads and poodles can walk on land, that's where the similarity ends.

Snakeheads' voracious appetites and lack of natural predators make them a serious threat to native species. These "stomachs with fins" have been found in the lakes and rivers of eight states, from Hawaii to Florida. In most cases, their release originated with pet owners.

Sadly, the snakehead isn't unique in this respect. Predatory Asian eels in the Everglades, seven-foot carnivorous lizards in the Florida Keys and venomous lion fish off the North Carolina coast all originated with hobbyists who found them to be too much trouble. These and other invasive species cost U.S. taxpayers an estimated $137 billion a year in economic losses and control costs. They also are the second-leading cause of species extinctions.

Like other harmful invasive species, the snakehead is outlawed by 16 states and the federal government. Maryland too should take strong action to prevent the spread of this destructive species.

CARROLL MUFFETT

Director of International Programs

Defenders of Wildlife

Washington