Sharks now have company in the water off Cape Cod. Portuguese men-of-war have arrived

It’s been the summer of the shark off Cape Cod with hundreds of reported sightings, but a new venomous creature is now making its presence known.

Harding’s Beach in Chatham was closed to swimmers Saturday afternoon after a number of Portuguese man o’ wars washed ashore.

Portuguese man o’ war sightings also closed Horseneck Beach Station Reservation in Westport on Sunday. The beach already closed once this summer for a man o’ war sighting.

The highly venomous ocean predator is sometimes mistaken for a species of jellyfish, but the man o’ war is actually a siphonophore that uses its feeding tentacles to sting and paralyze small fish, according to Oceana.

The man o’ war’s sting can be very painful to people, and officials say it is best to avoid swimming when there are large numbers in the area.

RELATED: A venomous ocean creature was spotted at a Massachusetts beach. Here are 5 things to know

Beachgoers should also use caution, as the species has the ability to sting weeks after washing ashore. Though their sting is rarely deadly to people, it packs a painful punch and causes welts on exposed skin.

These recent man o’ war sightings come after dozens upon dozens of sharks were scene lurking in the water near the shore at several Cape beaches.

Great white sightings off Cape Cod have skyrocketed in recent days as summer in southern New England shifts into peak shark season. A hammerhead shark was also recently spotted hunting for fish in the water near a beach on Nantucket.

Shark sightings typically peak from August through October, according to Megan Winton, a scientist with the Atlantic White Shark Conservancy.

Beachgoers are urged to be most vigilant when swimming off beaches where the shoreline quickly drops off into deeper waters.

Download the FREE Boston 25 News app for breaking news alerts.

Follow Boston 25 News on Facebook and Twitter. | Watch Boston 25 News NOW