Island police reported a busy weekend, among other things making a number of drunk driving arrests and breaking up several loud and disruptive parties.

Aquinnah chief Randhi Belain said police received a call around 1:30 p.m. from a sunbather who found an unusually large fish on the shore between Philbin Beach and the property owned by the Martha’s Vineyard Land Bank. When police arrived they found what appeared to be a 20-foot shark.

Police contacted marine biologist Greg Skomal, who identified the large fish as a basking shark, the second largest breed of shark in the world, behind the whale shark. The basking shark is a passive filter feeder, filtering zooplankton, small fish and invertebrates from up to 2,000 tons of water per hour.

Chief Belain said the discovery of the shark created a bit of a stir on the beach. Mr. Skomal performed an autopsy of the fish on Sunday.

Tisbury police made three drunk driving arrests over the weekend. On Sunday around 1:30 a.m., they pulled over 19-year-old Paul Massey of Larchmont, N.Y., on Beach Road and charged him with operating under the influence, negligent operation of a motor vehicle and marked lanes violation.

On Sunday at 1:44 a.m., police pulled over Amy Leonard, 21, and arrested her on charges of operating under the influence, speeding, negligent operation of a motor vehicle and marked lanes violation. Also on Sunday, at around 1:28 a.m., police arrested Alexander Lawson, 22, of Oak Bluffs, for operating under the influence, negligent operation and marked lanes violation.

West Tisbury police responded to a call of a domestic disturbance around 12:55 a.m. on Monday and arrested Patrick Caine, 32, on charges of domestic assault and battery.

West Tisbury police also responded to a call of a large party near Lambert’s Cove Beach around 11 p.m. on Saturday. When police arrived, they found a gathering that included high-school-aged kids, according to officer Dan Rossi. The party was broken up with no arrests, although an investigation is ongoing, Mr. Rossi said.

West Tisbury police received a call that someone had vandalized the light that shines near the front gate at the entrance to Pond Road; the investigation is ongoing.

In Oak Bluffs the weekend also brought a number of calls, including investigations into breaking and entering on New York avenue and on Laurel avenue. In the New York avenue case a homeowner had returned to find a vandal had not only taken items of value but had flooded the home by leaving water running in sinks and bathtubs.

On Saturday night police responded to a report of a suspected drunken driver who ran into a fence causing damage on Alpine avenue. Police subsequently arrested 56-year-old Terry Canha of Oak Bluffs, charging him with operating under the influence, negligent operation of a motor vehicle and vandalism.

Early Sunday morning Oak Bluffs police responded to a large late-night party involving local teenagers and alcohol. Police received a call well after midnight of a large party underway on Puritan Drive in the Tower Ridge development.

About 50 people were at the party. As police approached the house, many of the party goers dispersed. Police found alcohol had been served and began a room-to-room search for the home-owner. As they searched the house, more youths rushed out into the woods. Students who were 18 and above and had no alcohol were allowed to leave or take persons with them who had been drinking. Youths who had been drinking were released to parents or adults.

Though there were no arrests, police said they plan to investigate the matter, since there were no adults on the premises and alcohol had been served to minors. They said a court summons will be sought charging the homeowner for furnishing alcohol to minors. Police said a similar party was broken up at the same house a year ago.

Gazette reporter Mark Alan Lovewell contributed to this report.