Shark Bites Off Fisherman's Finger In Horrifying Video

Terrifying scene out on the open waters near Florida on Sunday ... a shark bit off a fisherman's finger -- and, WARNING, video of the incident is graphic.

The attack went down in the Content Keys -- just a few miles south of Miami -- when Brett Reeder was attempting to corral a 6-foot lemon shark that he had just hooked.

As Reeder went down to grab the beast and get his tool out of the fish's gills -- it suddenly turned and chomped down on his hand.

You can see in video of the bite -- which, again, is VERY graphic -- blood spilled everywhere ... 'causing Reeder to yell out, "F***! I lost my goddamn pinky! F***!"

Brett, according to a follow-up video posted by his wife, Mandy, had to drive the boat all the way back to shore following the bite -- while bleeding profusely.

Brett eventually made it back to land, and was immediately airlifted to the hospital. He underwent surgery upon arrival.

It's unclear if docs were able to save Brett's pinky in the operation -- the fisherman said in Thursday's follow-up video they'll find out the official results of the surgery later this week.