"We had cases last year where 30 boats were trailing right behind only two whales," said Ray Sautter of the National Marine Fisheries Service.

It was a day of the kind they make tourist brochures about, the bay deep blue and sparkling with the sun; toward Capri, the water looked greener, and the boats heading for the island trailed crisp, white wakes.

"Yes, Bailiff," said Tom, gesturing at the small boats still trailing offshore at the end of Retruance's tethers.

And if the boats were trailing acoustical detection gear, they would have to shut down the minisubs immediately so the sounds of their power packs wouldn't be de-tected.

Now, Jackson knows-"He watched as thecutter's painter was led aft, so that the boat trailed astern like a dog on a lead.

And a boat named Sinatra filled with American reporters trailed along farther behind.

The boat, by trailing the buoy, trails the animal.

The boat trails streamers to attract the big predators - by sound: the streamers make a noise like a fish struggling.

Adding to the excitement is that boats of all sizes and speeds - from rafts to speedboats to yachts - are allowed on the course and can trail the competitors, which they often do with bellicose gusto.