MOSS LANDING — More than a dozen killer whales staged a family reunion of sorts on Monterey Bay this weekend, meeting at a huge cluster of sea lions for an afternoon picnic.

The extremely unusual sight — one expert counted 19 adult and juvenile orcas — adds another chapter to a summer and fall on Monterey Bay that seems destined to go down in history. Hundreds of whales, epic schools of anchovies, frenzied pods of sea lions and now frolicking killer whales are all part of the story.

“This is a once-in-a-lifetime chance, so people should see it,” said Nancy Black, a marine biologist with Monterey Bay Whale Watch, who has decades of experience on the bay. “This is just unheard of. It’s unbelievable. Nobody has seen this anywhere in California.”

During the weekend, several families of migrating transient killer whales decided to take a detour in to the bay and — orcas being orcas — generally made a nuisance of themselves.

They scattered a flotilla of hundreds of sea lions feasting on anchovies, claiming the slow ones for a meal. They shooed away humpback whales who’d been dining peacefully nearby, and some of the youngsters even chased after sea birds.

Those families also joined a pair of killer whales who are repeat visitors to Monterey Bay and have been sighted frequently during the last month. Those whales have their own story to tell.

To observers, the two males are known as Stubby and Fat Fin. Fat Fin’s dorsal fin is more triangular than most, while Stubby earned his moniker because the top of his fin is severed.

The two often hang out together and have for years. Fat Fin, the younger one, is an orphan, and Stubby was either orphaned or left his mother. Fat Fin is especially social, often seeming to interact with tour boats to the delight of passengers.

They were joined by several families of whales in the past several days, all of whom happened to congregate for a family reunion that was far more photogenic than most.

“Most of the ones we see here are somewhat related to an extent, like cousins or aunts,” Black said.

AN EYE-POPPING YEAR

Whales have abounded since the summer.

From boats, kayaks and paddleboards, those lucky enough to find them in the water have been treated to a phenomenal show. And while the Marine Mammal Protection Act dictates viewers stay at least 200 yards back, the whales often unexpectedly come closer.

Misha Burich was on his deck on Capitola’s Depot Hill the first weekend in November, photographing whales, when one suddenly pushed the nose of a kayak skyward. The paddler appeared to escape being tipped over completely and retreated, but Burich has been irked by what he felt were tour boats following too closely.

“I don’t like people making whales be uncomfortable,” Burich said. “This is their habitat.”

All the marine activity seems to be fueled by lowly anchovies, which have been observed in huge numbers. It turns out that — like any party — food is the key to drawing guests.

“This is a record year for this feeding aggregation of humpbacks and sea lions,” Black said. “There’s just miles and miles of fish out there.”

Photographer Jodi Frediani said the summer and fall have been a thrill.

“Whale watching on Monterey Bay the past two months has been a veritable treasure hunt with an almost guaranteed treasure, if you just know where to look for it,” Frediani said.

Follow Sentinel reporter Jason Hoppin at Twitter.com/scnewsdude