LOS ANGELES — Joe Roper has been surfing off the coast of San Diego for five decades. He's rarely experienced water this warm.

"All of a sudden it has turned into a bathtub," said the board repairman. "It's insane. I've never heard of 80 degree water here."

Scientists on Thursday announced that the sea surface temperature off the coast of La Jolla, California, came in at 78.6 degrees — the warmest it's ever been in the 102 years measurements have been recorded. Earlier in the week, the National Weather Service (NWS) in San Diego recorded sea surface temperature of 80 degrees a few miles north, off Solana Beach.

The once-in-a-lifetime, tropical weather is sending hordes to the shores, but they're also changing the very nature of classic Southern California beach weather, long influenced by cool breezes and waters chilled by the north-to-south California Current. The NWS recently measured a dew point in San Diego of 70, which indicates an environment that feels positively sticky.

"It's over the top," says NWS meteorologist Alex Tardy. "It’s making the nights warmer, the days muggier and the sea breeze doesn't work as well as it usually does."

Sport fishing aficionados are nonetheless having a field day.

"Bluefin tuna has been here forever, but the volume in the last three to four years has been more than I’ve seen in my lifetime," said Ken Franke, president of the Sportfishing Association of California. "Right now there’s an incredibly large volume of bluefin tuna — anywhere from 10 pounders from 300 pounders, a couple hunderd tons in a single school."

Practitioners of sport fishing are limited by law to two bluefin a day per person, he says, but there's a wealth of other coveted seafood off the Southern California coast, including yellowtail and dorado. "It’s like going through a drive-thru at McDonald's for fish," Franke says.

Bait species, including anchovies, are plentiful, too, experts say. The bounty for those who fish, however, could portend harmful long-term changes.