FORT LAUDERDALE, Fla. (AP) _ Controlling the rowdy college kids is a chore in Fort Lauderdale during spring break, but it's the high school kids that really cause problems, police say.

An estimated 100,000 sunbathers and beer-drinkers packed the popular beach Sunday in the biggest single day of the eight-week spring-break period.

But Police Chief Ron Cochran said only about 30,000 to 50,000 would have been college kids from out of town. The rest were mostly high school-age youths, out to have fun just like their older counterparts, he said.

''It's just a chance to get into a rowdy scene, a drinking scene,'' he said. ''There is no other entertainment out there.''

The younger crowd tends to cause more problems. Of the 550 people arrested on Fort Lauderdale beaches during last year's spring break, only 105 were from out-of-town colleges, Cochran said.

Most of the arrests were for disorderly conduct, fighting, traffic violations or narcotics possession, he said.

''When they are out there, they don't say they're from Piper High or Ely High; they say they're from the University of Miami or Harvard,'' said Broward County Sheriff Nick Novarro. ''And their chests go out a few more inches pretending they are something they are not. If (parents) would keep them off the beach, it would make it a lot easier for us.''

The college kids come to Fort Lauderdale to blow off a little steam before heading back north to classes. Local school and law enforcement officials agree that the problem with the local youths is they take the one-week loss of all inhibitions as the norm.

''The college students are down here as a release,'' said Michael Kinghorn, principal of nearby Hollywood Hills High School. ''They're on vacation, and there's not a whole lot in common with what's going on on the beach and what they do the nine months of the year they're in school.

''But high school student are likely to misconstrue what they see on the beach as typical college behavior.''

Alonzo Lawery, a volunteer counselor at the Palm Beach House, a home for juvenile delinquents, works with the products of that environment.

''For a South Florida kid, it's more a lifestyle than a week-long break,'' he said. ''His values are centered around partying and just lying around.''