Conservationists in Florida have sued both local and national governments on behalf of the state's most beloved and endangered species, the manatee.

The lawsuit demands the authorities do more to protect this docile sea mammal from power boats, and the case has boat lovers complaining that their rights are under threat as well.

There is nothing a large, grey, passive elephantine manatee, or sea cow, likes better than lying just beneath the surface of South Florida's myriad waterways, soaking up the sun and munching gently on vegetation.

But as the constant roar of engines confirms, there is nothing most power-boat and jet-ski owners enjoy more than thrusting through the water at more than 30 knots, and faster if possible.

A booming American economy means more people are buying boats and more manatees are getting killed as a result.

Boating conflict

It is estimated that more than 80 sea cows died in collisions last year - a 20% increase on 1998. Only about 2,400 are left.

The lawsuit, filed by a coalition of conservation groups, calls on the state of Florida, the US department of the interior and the US army corps of engineers to fulfil the requirements of laws designed to protect the manatee.

Among the measures the conservationists want are: tougher police action against those who ignore speed restrictions in manatee zones, more manatee refuges and a ban on building facilities, like marinas, boat ramps and docks by new waterfront properties until local authorities have implemented plans to protect manatees.

A spokesman for the recreational marine industry said the lawsuit was not the way to solve this issue; he complained that the manatees' problems had frequently been used by local and national governments to hold back access to the water.

"Boaters have rights, too," he said.

The local fishery and wildlife commission argues that there are not enough police officers available to catch speeding boaters.

But the conservationists warn that, unless they act now, they will soon have to choose between killing off the manatee population completely or restricting boats so severely that messing about on the rivers, canals and bays of South Florida will no longer be such fun.