Spring Breaker Arrested After Man's Ear Bitten Off in Beach Brawl

An 18-year-old spring breaker landed himself in the slammer after allegedly biting off another young man's ear during a St. Patty's Day brawl that went down on Fort Myers Beach in Florida.

Jack Turner was arrested by the Lee County Sheriff's Office just after midnight on Tuesday after they obtained video that captured the fight -- and the gruesome act that left the victim with his ear detatched from his head.

A police report obtained by TMZ paints the horrific scene ... video reportedly shows the victim -- identified as Juwan Black -- lying face-down in the sand as Turner mounts his back. Turner allegedly strikes Black in the back of the head multiple times with clenched fists before grabbing his hair and pressing his head into the sand, per the report.

Police say Turner then yanks Black's head upward as he goes in for the bite ... leaving the victim's left ear with "traumatic auricular amputation."

A witness told police she was walking down the beach with Black when Turner began slinging racial slurs at him ... eventually striking him from behind.

She believes Turner attacked Black because he is a homosexual Black male. Black stood up for himself by getting into a fighting stance ... which is when, the eyewitness told police, the physical altercation ensued.

Black was treated for his injuries at Gulf Coast Hospital.

Turner was released from jail after fulfilling a $50,000 surety bond. He is due to appear in court on April 21.

We're told Black and Turner previously knew each other.

The Lee County Sheriff’s Office Violent Crimes Unit took the case, and the investigation is ongoing.

LCSO tells TMZ ... Sheriff Carmine Marceno has "ZERO tolerance for violence of any kind" and that "Fort Myers Beach will continue to remain safe for all visitors and residents of Lee County."