WECT-TV reports that the man was struck about 3:15 p.m. on Sunday.
The New Hanover County Sheriff's Office responded with their Marine Unit, along with Wilmington Police Department's Marine Unit.
A spokesperson for the sheriff's office said it's not clear whether the man was on the island or in a boat when he was struck.
Deputies performed CPR on the man as they were taking him to Bradley Creek Marina to meet emergency medical personnel. He was taken to the hospital, but his condition could not immediately be determined on Monday.
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