California marine heat wave disrupts whales, sea lions and sharks as waters warm

A marine heat wave along the California coast is disrupting wildlife patterns, with scientists and guides reporting fewer whale and dolphin sightings, risks to sea lions and more great white sharks seen closer to shore.

The US National Oceanic and Atmospheric Administration said surface water temperatures along the California coast are three to four degrees Celsius above normal. Andrew Leising, a NOAA research oceanographer, told AFP the current heat wave has lasted about six months.

Sara Lesser, a naturalist at the Aquarium of the Pacific in Long Beach, said tourist boat trips are seeing fewer whales and dolphins than in a normal year. She said warmer surface waters are pushing anchovies and sardines, their food, into deeper or more northern waters.

The heat wave is coinciding with the return of El Nino, which warms parts of the Pacific and can disrupt global climate. Leising said this El Nino could be stronger than the 2015-2016 event, when a marine heat wave contributed to major harm to birds, sea lions and whales in California.

In recent months, dozens of pelicans and cormorants were found dead near San Diego. Leising said he fears sea lions could soon suffer as warmer waters force females to leave pups while hunting for food and as toxic algae blooms contaminate anchovy and sardine populations.

In Monterey Bay, south of San Francisco, harmful algae have been widespread, and two humpback whales were found dead ashore in early June. Elliott Hazen of the University of California, Santa Cruz, said the deaths highlighted the amount of domoic acid in the ecosystem.

Lesser said younger great white sharks prefer warmer waters and are being seen closer to shore. The article also reported a recent Malibu video showing a white shark near children and three spring swimming bans at Huntington Beach because of sharks deemed aggressive.