Salmon scout out creek days before festival
With Lake Tahoe’s eighth annual Kokanee Salmon Festival ready to open on Saturday, only a few of the featured fish have begun the arduous journey up Taylor Creek to their traditional spawning grounds.
While the number is still small compared to last year’s robust run, biologists expect more salmon to fight their way up the stream by Wednesday, when the amount of water released into the creek from Fallen Leaf Lake will be doubled.
The new channels carved by this year’s floods are expected to do little more than confuse the kokanee for a short time.
“I have faith in the evolutionary drive of the fish. It’s amazing what these fish will go through to spawn,” said Jeff Reiner, a fisheries biologist with the U.S. Forest Service’s Lake Tahoe Basin Management Unit.
The relatively late run – last year the fish were schooling in the Creek by mid-September – is not unusual, and probably due to recent warm weather, Reiner said.
When they return, the spawning salmon will find a Taylor Creek that is radically different from the stream where they were born two to four years ago. The New Year’s Day flood of 1997 scoured out the main stream channel, leaving some spawning beds high and dry, but improving the habitat in other areas.
“It’s a pretty nice looking stream,” said Reiner, who has walked its length three times in recent weeks removing debris from the stream channels. “The new channel has more cover, so when the eggs hatch out, the fry won’t be exposed to as many predators. There’s probably about the same amount of spawning ground, but it’s in different places. There’s a bit more at Rainbow Bridge, and less at the highway.”
Like all Pacific salmon, members of the Oncorhynchus genus, kokanee salmon return to the stream of their birth, where they aggressively pair off, spawn and die. Atlantic salmon, by contrast, live to spawn again, but they belong to the trout, or Salmo, genus.
As they prepare to spawn, the fish undergo dramatic physiological changes. They stop feeding, and gradually absorb their fat, muscle and organs. They develop a characteristic red coloring, a humped back and jutting lower jaw.
While not native to Lake Tahoe – they were accidentally introduced in 1941 – the kokanee salmon have become a significant part of the basin’s food chain. Other animals practically line up to prey on the 200-1,000 eggs each female lays, or gorge on their wasted flesh once they die.
Among the animals that feast on the eggs are such introduced species as crawfish, bullfrogs and rainbow trout, as well as garter and king snakes and aquatic insects. After the salmon die, bald eagles, bears, gulls, kingfishers and raccoons feast on their remains, with raccoons devouring the lion’s share of the spoils.
According to Forest Service naturalist Gay Eitel, in the past large rainbow trout have exploited the annual fall bounty in Taylor Creek’s Stream Profile Chamber.
“The rainbow will learn how to harvest the salmon eggs,” Eitel said. “I have seen them push the salmon up against the glass, and repeatedly butt them so they will release the eggs,” Eitel said.
On the other hand, the naturalist has observed a male salmon defend its mate by ramming the predatory trout and killing it.
In other words, nothing will stand in the way of a kokanee salmon and its genetic destiny.
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