When it comes to Castaic, it’s all about the bait

The Castaic fire is contained, the wind has settled and the town’s namesake reservoir has reopened for business.

But it’s a surreal afternoon on the water. Lingering smoke obscures the sunlight and there are no other people in sight.

Marc Mitrany and I have the lake to ourselves and can hardly believe our good fortune as we make our first stop.

Beyond our bow, against a grassy shore, dozens of large bass have corralled a school of shad and are devouring the smaller fish in whooshing gulps.

Both predator and prey are practically beaching themselves in the frenzy. Mitrany has come prepared; earlier he had used a net to fill his live-well with shad.

I fling one into the fray and seconds later the line flies from my reel. I’ve hooked a monster and fear being spooled.

“We might have to chase that one,” Mitrany says. But the quarry has changed tactics and sprints toward the boat, causing me to frantically reel in the slack.

It then dives straight down, again and again, until, finally, it’s subdued and comes to color. It’s not a huge largemouth, as I’d expected, but a striped bass weighing perhaps 12 pounds.

Mitrany scoops it into his net and looks at me as though to say, “This is what the live-bait bite at Castaic is all about.”

He then tosses the beautiful fish back and we continue on our strange and wonderful journey.

Castaic Lake, 40 miles northeast of Los Angeles alongside Interstate 5, has for decades been a popular bass fishery.

It has produced largemouth bass upward of 20 pounds and stripers upward of 30 pounds, but as the striper population slowly increased, the number of gargantuan largemouths seems to have slowly declined.

Still, it remains a robust fishery, thanks to the abundance of threadfin shad, which rise to feed each late summer and fall in anticipation of the long, cold winter.

When this happens, largemouth bass and stripers focus on this prey source. And fishing, for those able to catch shad, can be ridiculously wide open.

“If you’ve got the bait, you’re pretty much going to catch fish all day,” says Mitrany, who runs Ojai Angler guide service and also leads trips at Ventura County’s Lake Casitas.

The shoreline frenzy is short-lived, though, so we’ve moved to a nearby cove and begin to methodically reel in largemouth bass averaging 2 to 5 pounds.

Mitrany had been doing this with clients almost daily before a Santa Ana wind, which fueled the nearby fire, led to a days-long closure of the launch ramp.

We’re here on a Friday afternoon, a day after the ramp reopened, as the nearby hillsides smolder.

Our only visible company are gulls soaring errantly overhead and three snowy egrets, standing motionless on the bank, waiting for passing fish.

What I find amazing is the behavior of the bass during the shad run. Often they’ll tail-slap the bait first, then return to inhale the stunned fish.

So for an angler fishing six-pound test with no weight, there is the initial surface boil, a brief period of intense anticipation, then the actual strike.

In fact, fishing with shad is a lot like fishing with sardines in the ocean. And the action, I’ve learned, can be almost as fast as it is during a wide-open tuna bite.

Mitrany agrees and points out that there are purists who won’t use shad or any type of live bait, favoring only artificial lures such as swim-baits or plastic worms.

“But to me, fishing is fishing,” the guide adds, while admiring another three-pound largemouth. “I’ll use whatever’s working best at the time.”

We’ve caught at least 40 fish before the sun dips over the western ridge, casting a cool shadow over the cove.

It’s time to head back, but out of curiosity we stop at the spot where I caught our lone striper. There is no churning frenzy but I cast anyway, and two seconds later my reel is singing again.

It’s another large striper, a perfect bookend, bringing to a fitting end the best afternoon of bass fishing I’ve ever enjoyed. And if this is what the Castaic live-bait bite is really about, I’ll rue the day the shad go deep, and long for their return.

Briefly

* Wax the boards: A late-season swell generated in the Southern Hemisphere -- perhaps the largest of this miserable season -- is expected to arrive early next week, finally giving surfers something to cheer about.

Coincidentally, Surfline.com forecasters Kevin Wallis and Graeme Rae, on Tuesday night, will give a presentation on forecasting and swell dynamics at Aquarium of the Pacific in Long Beach. Time: 7 p.m. Cost: $7, or $4 for aquarium members. Details: (562) 590-3100.

* Big marlin, mega bucks: The San Diego team aboard Angel and the Badman II captured a 620-pound blue marlin to claim first place during the recent Bisbee’s Black & Blue tournament off Cabo San Lucas. The payoff: $734,415.

That wasn’t the biggest payoff, however. An Arizona team aboard Bad Company came in third with a 539-pounder but, because it had entered all the side jackpots, won the most money: $1,421,752.

In all, 166 teams competed for $3,838,620 in the world’s richest billfish tournament.

* Great adventure: Renowned guide Doug Stoup has embarked on an expedition with three Englishmen to follow Ernest Shackleton’s planned 1915 “Imperial Trans-Antarctic Expedition” route to the South Pole. The route was never actually attempted by the famed explorer because his ship, Endurance, was destroyed by ice. Stoup’s group will drag sleds over the frozen landscape. His expedition website: Beyondshackleton.com.

pete.thomas@latimes.com