Fisherman line the rail under the lights of the Western Pride hoping to catch a Humboldt squid during a trip to the waters off San Onofre State Beach. (Don Leach / January 10, 2013)

It was almost midnight when someone spotted the banana.

Word on the boat spread quickly. Guys in the back corner were snacking on a bunch, people said, but it was unclear if they threw the talismanic fruit overboard.

No matter — the damage had already been done.

The Western Pride — a no-nonsense, 76-foot Ditmar that had taken off from Davey's Locker Sportfishing and Whale Watching in Newport Harbor about five hours earlier Wednesday evening — was headed back to port without having hooked a single squid.

The 75 or so anglers onboard anticipated waters teeming with Humboldt squid, which are known for their mysterious sudden invasions of California coastal waters.

"This is a natural occurrence that happens periodically since about 2003, although we are not exactly sure why," California Department of Fish and Wildlife marine biologist Dianna Porzio wrote in an email. "Humboldt, or jumbo squid, is a short-lived species that has experienced a range expansion in the last decade or so and are probably feeding and spawning off our coast, but they are normally found in deeper water."

Sometimes, though, they ascend from the depths, making for massive sportfishing hauls.

Sunday night alone, about 15 anglers reeled in approximately 340 squid within about an hour near Dana Point, Rob Armes of Davey's Locker said earlier in the week.

The only reason they didn't catch more was because they didn't have enough anglers.

"If we'd had 40 or 50 people, we'd have gotten 800 to 900 squid," Armes said. "They were floating all around the boat. They were jumping. They were everywhere."

Squid-fishing excursions have been leaving from Dana Wharf nightly since late last week, said General Manager Donna Kalez, and have been coming back with hundreds.

The cephalopods, which in warmer waters can grow to the size of a small person, Armes said, "eat everything in their path."

"They eat fish, they eat each other, anything," he said, adding that the squid chow down on the types of fish anglers usually try to catch.

Porzio said there are no state season or bag limits on Humboldt squid, other than a general invertebrate bag limit of 35.

The problem is predicting when — and for how long — they'll bite.

Wednesday, Anglers had lined up at nightfall, bundled in thick jackets and beanies, or sporting classic yellow slicker suits, drawn by frenzied reports of the squids' arrival off San Diego and Orange County.

Bao Cao, a Fountain Valley resident working in the financial industry, recalled hitting gold on a "crazy" calamari harvest a couple years ago.

"Most likely everyone's going to be soaked with water and ink," he said as he tied a glow-in-the-dark squid jig to a line.

Crew members fillet the squid onboard for $3 a pop, Western Pride crew member Paul Rodriguez said, because the city of Newport Beach "frowns on" the ink stains they leave on cement.

Ripin Young, who said she'd nearly had a panic attack sitting in traffic from San Bernardino, chatted excitedly with her brothers Thomas and Ting about the evening's prospects.