CORONADO, Calif. - San Diego Bay has a new tenant that could mean bad news for other marine life.

Birch Aquarium specialists said the Australian spotted jellyfish have been around the area for 20 years, but their numbers may be increasing due to rising water temperatures.

"It's like an alien cauliflower," said Coronado Cays resident Daron Case, who goes by "Captain of the Cays."

Case said he first noticed the jellyfish last summer but noted there are definitely more this year.

"They're about the size of a basketball," he said.

Case told 10News some people are now afraid to go in the water, adding, "They're definitely scared to swim in the bay. None of them like to see these jellyfish because of course they're afraid of getting stung."

Birch Senior Aquarist Vince Levesque said the sting is very weak and won't even make it through your skin.

However, he did warn you still don't want to be stung near the eyes, mouth or open cuts.

Case said he's done some of his own research. He said he's worried about the other marine life in the bay.

"From what I've heard, they filter thousands of gallons of water per day including consuming a lot of nutrients that are intended for the local marine life," he said.