A record number of shark-bitten sea otters have been reported along the California coastline in the past couple of months, prompting state officials to warn of a potentially increased threat to humans.
Scientists collected 19 injured or dead otters with signs of shark bites in August, and seven more have been collected so far in September.
The majority of the animals have been found in San Luis Obispo County near Morro Bay or Pismo Beach, but others have been found in Monterey Bay or near Ano Nuevo State Park in southern San Mateo County, according to Mike Harris, an environmental scientist with the California Department of Fish and Game.
Harris said 19 otters is a record for any month in California and a clear sign of “an increase in shark activity in this area like we’ve never documented before.”
Department of Fish and Game spokeswoman Carol Singleton said white sharks, the predators believed to be responsible for the deaths, thrive in colder waters.
“Because we had a really mild summer, it’s ideal for white sharks,” she said.
Otters are not the preferred meal of the sharks, so not all of the otters attacked are killed, she added.
“We think they’re mistaking otters for what they usually eat: seals and sea lions,” Singleton said. “They’re not consuming them; they just seem to be biting them and going, ‘Oh that’s not what I like,’ and moving on.”
The sea otter population is also being affected by other problems, such as toxic algae and other contaminants, which Harris said are combining with the shark-caused deaths to create “a population-level impact” on sea otters in the state.
Because of the increased shark activity, Fish and Game officials are advising swimmers, divers, surfers and other water enthusiasts to avoid Bay Area locations known for white sharks—including Ano Nuevo, Bird Rock in the Point Reyes National Seashore, and the Farallon Islands—and to remain aware of their surroundings in the marine environment.
It’s unclear whether there are more sharks in the region or if those that are there are more active, Harris said. There is not much data on the white shark population, he said.
White shark attacks on humans are extremely rare though in California, which has had 95 attacks since 1950. Eleven of those were fatal.
The advisory “is not to discourage people from getting in the water, but we’re giving them the information so they can make their own decisions,” Harris said.
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