Gone Fishing

GONE FISHING: After shooting three films in a row (including this summer's Wyatt Earp and The War), Kevin Costner plans to take a year off once his $60 million adventure Waterworld is complete. A spokeswoman at the actor's Tig Productions refused to speculate on how Costner will spend his sabbatical, but here's a clue: Shortly before the announcement, Costner was spotted fly- fishing in Big Sky, Mont., spending day after day in the icy-cold Gallatin River. ''A very competent and confident fisherman,'' says a guide, who notes that the star managed to reel in some rainbow and brown trout. Sounds like he's hooked.