For the second time in a week, Martin County waters closed off to swimmers.
There's a warning for those who may be headed to the beach in Martin County.
They are being urged to keep a close eye on the water, after sharks were spotted twice in one week. After a suspected attack on Monday in the waters off Jensen Beach, lifeguards Wednesday shut down guarded sections of the beaches in Jensen and Hobe Sound, after spotting sharks offshore.
Waters were off limits for about a half hour, until the sharks left the area.
Shark sightings typically follow a migration of bait fish, but these sightings are coming at a time where there haven't been any reports of such a migration.
Meanwhile, lifeguards say if you see a large school of bait fish moving through the water, you should get out and wait until they pass. They also recommend that you swim only in guarded areas of the beach.