By Jim Taylor
"Keep Tahoe blue" — the longtime catchphrase for the mountain lake in the Sierras could instead become "keep Tahoe clear."
Lake Tahoe's declining clarity has a lot to do with shrimp, according to Dr. Geoffrey Schladow, founding director of the UC Davis Tahoe Environmental Research Center.
The microshrimp were introduced to Lake Tahoe in the 1960s and the intention was to provide food for the fish in the lake, but the move didn’t go as planned.
“What [the shrimp] have succeeded in doing is destroying the native food web of the lake,” said Schladow. “What [the shrimp] essentially have done is eaten the zooplankton, the native very small animals that feed on the algae.”
Fewer plankton present in Lake Tahoe’s waters means more algae and less clarity.
Now, experiments are being conducted in Emerald Bay to restore the clear waters that made Lake Tahoe famous.
“A lot of money [is already] being spent on stopping fine particles and nutrients from entering the lake,” said Schladow. “This next phase is demonstrating the potential to actually restore the native food web of the lake and bring it back to full health.”
The plan includes trolling Lake Tahoe for the invasive shrimp, so that the zooplankton can thrive and gobble up the clarity-killing algae.
“What we’ve been investigating is how to find [the shrimp] and where they are located in Emerald Bay and the rate at which they can be trolled for,” said Schladow. “When the shrimp naturally disappeared from Emerald Bay for a two-year period, the clarity of Emerald Bay went up 30 feet in that period of time.”
