An astonishing 230,600 salmon -- nearly all sockeyes -- on Sunday passed through the sonar counter 19 miles upstream from the mouth. Some years, the peak day's total doesn't even hit 100,000.

Those are the fish that escaped the commercial nets, the dipnetters, the lower Kenai rod-and-reel fishermen and anything else that might want to eat them. Many will go on to spawn and produce salmon that will return to the river in four to six years.

Over the weekend, dipnetters were pulling in reds one after another, sometimes finding two or more flapping fish in their nets at once.

"It was unbelievable. I've heard stories but I never expected anything like this," said Chuck Pratt, 46, who works as a fish biologist at the Fort Richardson hatchery and had been dipnetting a few times before.

"People were getting doubles and triples," Pratt said. "I had a triple, three doubles and a single" in one short time span. One woman hauled in five reds in one sweep down the beach, he said.

Another big slug of salmon came on the tail of Sunday's surge. A count midday Monday showed that 73,000 salmon had reached the counter compared with 79,000 by that time Sunday.

So if you're a dipnetter or sport fisherman and didn't get to the Kenai this weekend, did you miss it?

Probably not. Fishery managers estimated that less than a third of the number of salmon expected to make it into the river had come through by late Sunday.

"There are going to be plenty more good days of dipnetting to come," said Pat Shields, acting area management biologist for Upper Cook Inlet commercial fisheries.

NEW SONAR, MORE FISH

The previous biggest one-day total was 218,000 salmon, back on July 21, 1987, according to a newly revised figure from Fish and Game. The state began compiling its database on Kenai salmon counts in 1978.

This year, it began using a new kind of sonar that essentially takes in a bigger area and counts more fish in certain rivers, including the Kenai, according to the agency. The state ran the two sonar systems side-by-side for three years and found that the new system registers roughly 40 percent more fish. The state converted past counts to be comparable to this year's numbers, though its Web site hadn't been updated as of Monday afternoon.

While Sunday's record surprised state biologists, they knew going into the weekend that salmon were piled up in Cook Inlet waiting to push into the rivers.

An offshore test fishery in which the state contracts with a drift gillnet vessel to fish six spots daily was posting excellent numbers, Shields said. The fishery helps the state evaluate how many reds are coming into the inlet and serves as a check on its salmon forecast.

Anything over 100 -- representing the number of salmon caught in an hour on a certain size net -- is considered a good sign. On July 10, the state reported 257, a big jump from the day before, and the test fishery markers stayed high, reaching 378 on Friday.

DECENT RUN IN THE MAKING

On Thursday, the commercial drift fleet "had a very, very big day of fishing," catching an estimated 700,000 salmon, Shields said. But the commercial setnetters fishing from shore only caught 27,000. And many dipnetters were skunked or nearly so. Few reds had reached the beaches.

Even after salmon arrive in the upper inlet, it can another three to 12 days for them to make their push to their home river, Shields said.

By Friday night, dipnetters at the Kenai and the Kasilof rivers began to clean up. On Saturday "those fish made a charge to the eastside beaches of Cook Inlet and the setnetters had a phenomenal day of harvest," Shields said.

Fish managers aim for an ideal number of salmon -- 700,000 to 1.2 million -- to make it into the Kenai River and spawn. Too few salmon means there won't be enough salmon returning in a few years. But too many can overload the river with juvenile salmon and hurt future runs.

With so many fish coming in so early, fishery managers are allowing extra commercial fishing periods, beyond the scheduled Monday and Thursday openings.

On Saturday, even with commercial setnetters and drift boats fishing, the Kenai dipnetters were slaying thousands of fish. Rod and reel fishermen on the lower Kenai had an exceptional weekend, too.

The fishing for the drift fleet slowed, while setnetters on the beach harvested about 450,000.

The fish travel another one to three or more days from the river's mouth to reach the sonar counter upstream. So some of Sunday's surge headed into the river on Saturday, making it past a gantlet of nets and lines.

"There's a belief that when the commercial folks are in the water that no fish get into the river. I think we've proved that not to be the case," Shields said.

The wave of reds hasn't made it to the Russian River yet. That could take another week, say fish biologists.

BIG TIME FOR DIPNETTERS

Dipnetting has become a wildly popular way for regular Alaskans to fill their freezers. A head of household can keep 25 salmon, with another 10 for every family member.

Pratt was discouraged after dipnetting at the Kenai during the slow spell the week before. But a newbie in his group, Gretchen Nelson, heard from a neighbor that things had picked up.

When they returned to the Kenai Sunday afternoon, a steady stream of vehicles with dipnets tied to their roofs was going the other way, back to Anchorage. That was a good sign that someone was catching fish.

His group of five people with three household permits started fishing around 5 p.m. and by 11 p.m., when dipnetting shuts down for the day, they had dozens of reds. They caught most on the outgoing tide, when stronger dipnetters form a sort of conga line and walk one behind the next, their poles stuck out into the water, hoping the salmon will swim into theirs. In all, counting a few caught Sunday morning, they ended up with about 80 salmon among the three households.

"Doing the conga line, it was hard to make a drift without catching a fish," Pratt said.

People made room for new arrivals and rooted for everyone else, he said. When a guy's homemade net with a crutch for a handle broke, people helped him repair it on the spot.

"Instead of combat dipnetting, it was cooperative dipnetting," Pratt said.

Nelson, 53, fished with a borrowed net, borrowed waders, even a borrowed fillet knife. She said it was raining Sunday but everyone was so busy catching, killing and cleaning fish that no one noticed.

"I'm hooked," she said.

Reach Lisa Demer at ldemer@adn.com or 257-4390.