Sharks are lingering off the California coast in record numbers, with a university shark lab tagging three times as many as in 2019.

“This year there were just more sharks around,” said Chris Lowe, director of the California State University, Long Beach, Shark Lab, KCAL reported. “And the question is why.”

The lab has tagged 38 sharks off Southern California so far in 2020, tripling the number tagged in 2019, CNN reported. Lowe called it the “biggest summer that we’ve had in the 10 years we’ve been doing this,” even though coronavirus precautions have hindered the lab’s efforts.

“What’s interesting is that the sharks are sticking around this time,” Lowe said, according to the network. “Usually they find a beach and stay there for a couple of weeks before dispersing and going to another hot spot.”

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Lowe said sharks also are showing up off beaches they rarely visited in the past, including those near San Diego, CNN reported. Food sources or climate change could be one reason.

“Normally in our fall when our water temperature gets to the low sixties, that seems to be a cue that drives them to migrate south to Baja,” Lowe said, KCAL reported. “And so far, here we are mid-October, and the sharks are still sticking around. Maybe 2020 is going to be a year-round shark season.”

Climate change also has been cited as a possible explanation for a rise in fatal shark attacks in Australia, BBC News reported.

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Sharks have killed seven people off Australia’s coast so far in 2020, nearing the 1929 record of nine deaths, according to the network. But the number of shark attacks is only slightly higher than the average of 20 per year.

Experts said runoff from higher rainfall may change shark eating habits, but emphasized that it’s hard to offer an explanation given the small sample size, BBC News reported.