Authorities were still searching Friday for a man who went missing after falling off a boat at Delaware State Park Thursday.

Stephanie O’Grady, a media & outreach specialist with the Ohio Department of Natural Resources, reported Friday afternoon that ODNR was still searching for a missing boater on Delaware Lake.

O’Grady said ODNR officers responded to a 911 call just before 9:30 a.m. Thursday and found one person unconscious in the water. O’Grady said that individual was taken to a local hospital. The condition of that individual is not known at this time.

Columbus media outlets reported Thursday that the two individuals were brothers on a fishing trip.

O’Grady said a second person is believed to be missing, and officers continue to search for the individual. The search was paused Thursday night and resumed Friday morning.

“ODNR reminds watercraft users that water temperatures in lakes and streams are still very cold, and even the best swimmers could experience exhaustion and symptoms of hypothermia in just minutes,” O’Grady said in an email Friday.

ODNR reports that “nearly 90% of boating fatalities are due to drowning and nearly half of those are attributed to the effects of immersion in cold water.” The department said that water cooler than the normal body temperature of 98.6 degrees causes heat loss, and cold water will cool a body 25 times faster than cold air of the same temperature.

ODNR also stressed the importance of wearing a life jacket, adding it is “as important as wearing a seat belt while driving.”

More information about water safety can be found at ohiodnr.gov.