A 24-year-old man has been bitten by a shark off Second Valley on the Fleurieu Peninsula, south of Adelaide.

Paramedics have treated him at the boat ramp at Wirrina Cove and he will be taken to Yankallila for further treatment.

It is believed he was bitten on the hand and lower leg by a shark measuring about two metres.

Locals say there have been a number of shark sightings between Normanville and Carackalinga in the past month.