“I love swimming here because I can see everything on the bottom, and I don’t have to worry about accidentally touching a fish. I don’t think there are any,” I overhear a little girl say while splashing in the clear, teal waters of Skunk Harbor.
For many swimmers in Tahoe, the underwater world of the alpine lake that plummets to a maximum depth of 1,644 feet is a total mystery. In part, that’s because it’s rare to see fish swimming anywhere near the water’s surface.
But 60 to 100 feet below, there are massive schools of fish circling the lake — from lake trout and mountain whitefish to rainbow trout and Tahoe suckers. The life cycles of these fish, however, pale in comparison to the fascinating journey of the kokanee salmon.
From its questionable “accidental” introduction into Lake Tahoe to the fish’s return to its home creek for spawning, the kokanee salmon tells a story of the interconnectedness of Tahoe’s underwater ecosystem.
ACCIDENT OR EXPERIMENT?
Kokanee salmon were introduced into Lake Tahoe in 1944 by a fish hatchery in Tahoe City, but the circumstances surrounding their introduction are murky.
“We’ve heard two different versions,” says Jean Norman of the U.S. Forest Service Lake Tahoe Basin Management Unit’s interpretive services department. “One is that a couple of employees were out cleaning the tanks and, oops, it overflowed and some of the fish rolled into the lake. The second version is that they decided to experiment and see if the kokanee would take to the lake and released fingerlings on purpose.”
And take to the lake they did. After a few years, the kokanee began to spawn in Taylor Creek, and annual stocking of salmon fingerlings began soon after, to the delight of sport fisherman (though that ceased just a few years ago).
At maturity, the blue-silver kokanee grow to roughly 12-16 inches in Lake Tahoe where they feed primarily on zooplankton.
“They swim in large schools, usually clockwise, circumnavigating the lake over and over throughout the year,” explains Norman.
HOME IS CALLING
In late September, the Forest Service increases the flow of water from the dam at Fallen Leaf Lake through Taylor Creek and into Tahoe.
“When fall rolls around, the fish sense the drop in temperature and the change in light due to shorter days,” says Norman.
Taylor Creek, a 2-mile tributary in South Lake Tahoe, is the ideal spawning ground for the kokanee due to the creekbed’s pea-sized pebbles that allow the fertilized eggs to be concealed while still receiving oxygen from the water’s flow.
“When a salmon is hatched, the smell of its birth place is imprinted. And after circling the lake over the years, the salmon knows all the distinct smells of the creeks and which one is home,” explains Norman.
While drought years have forced salmon to attempt to spawn in another of Tahoe’s 63 tributaries, Taylor Creek remains the primary spawning ground for the kokanee.
Sensing the change in seasons and the smell of its birthplace, the salmon congregate at the mouth of Taylor Creek as they slowly begin to transform in anticipation of spawning. The females turn to pink with green tinges, while the males take on a deep red and develop a hump on their back, a hooked jaw and sharp teeth. It’s all about attracting a mate and fending off aggressors that may try to interfere with procreation.
“The male is trying to attract the female, and when he heads up Taylor Creek in the fall, he is the one that has to be a smart fish to find the right location to have their rocky nest known as a redd,” says Norman. “If it has small pebbles, it’s a good location, and he’s going to stake it out and patrol it and not let any other males take it.”
If a female deems the male attractive and the redd well-selected, she turns on her side and uses her tail to dig a 4- to 6-inch deep hole where she deposits her eggs. Depending on her age, between 2 to 4 years old, she lays anywhere from 400 to 1,200 eggs, sometimes in multiple redds.
During this time, Taylor Creek is flush with bright red salmon, and it’s a sight to behold. The Taylor Creek Visitor Center has a boardwalk that follows the creek with educational information for all ages. Though a rarity, some visitors may catch a glimpse of a black bear taking advantage of the ample food source.
October is the month for peak viewing, with the Forest Service’s family-friendly Fall Fish Festival slated for Oct. 3 and 4; however, there are still fish to be seen in late September and November.
CIRCLE OF LIFE
After fertilization, the male covers and guards the redd. Both mother and father begin to decompose during this process — a sad but necessarily truth that contributes to the survival of their offspring. Having stopped eating, the female dies a couple of days after laying her eggs, while the male can live up to two weeks to protect the redd.
The roughly 1% of eggs that do survive will hatch three to five months later and remain hidden under the gravel for another two to three weeks before emerging into Taylor Creek as a “fry.” During this time the fry must avoid predators like brown trout and ducks.
Facing upstream, the fry eats nutrients in the creek created, in large part, by the decomposition of the spawning salmon, who have made the ultimate sacrifice for the survival of their offspring. Soon the fry will grow to a fingerling size and head out to the lake.
And in a couple of years, as the leaves begin to change, the days shorten and the temperatures drop, these very salmon will begin to feel the draw of home — they know the smell well — and return to Taylor Creek to begin the cycle all over again. The circle of life, indeed.