Aquatic invasive species a constant struggle
By Kathryn Reed
MEYERS – What’s living and growing in Lake Tahoe wasn’t always here. Some of the non-native or aquatic invasive species were intentionally introduced to the waters and others were surreptitiously brought here.
No matter their course of arrival, the AIS as they are better known, are altering the ecosystem. The Eurasian milfoil that is so prevalent in the Tahoe Keys is a breeding ground for warm water fish like big mouth bass. Neither of these two organisms is native to Tahoe.
At the fifth annual AIS Forum at Lake Tahoe Golf Course on May 21 various people spoke about what is being done to deal with some of the AIS that are here and how to keep out ones that aren’t. The major AIS already calling the lake home are curly leaf pondweed, Eurasian milfoil, warm water fish, Asian clams and bullfrogs. The three AIS that could be most devastating to the lake are New Zealand mud snails, Quagga mussels and zebra mussels.
Mats at the mouth of Emerald Bay suffocated invasive clams. Photo/LTN file
A multi-year project that ended six months ago with the removal of the mats from Emerald Bay showed a 80 percent mortality rate for the Asian clams. While it was deemed a successful project, it was also called expensive.
This fall a different mechanism will be used to help eradicate the clams from a spot at Emerald Bay. Aqua Treasures has been hired to use a Zamboni-like machine that will remove the shells as they are separated from the substrate.
The Tahoe Keys Property Owners Association expects to have the draft Integrated Weed Management Plan done in September, with associated environmental documents completed in February 2017 and implementation of the plan beginning in mid-2017.
The Tahoe Keys is blamed for the spread of milfoil to other parts of the lake. Photo/LTN file
Milfoil is choking more than 80 percent of the lagoons in this South Lake Tahoe enclave. Harvesters have been the traditional method for pulling up the weed, but it is costly and ineffective. In 2014, 18,600-cubic-yards of milfoil were removed from Keys. In 2007, 4,400-cubic-yards were taken out. Herbicides and bottom barriers are being considered as alternative methods.
Scientists at UNR and the Desert Research Institute did tests on Quagga mussels from Lake Mead with water from Lake Tahoe. Eighty percent of the adults and 80 percent of their offspring could live in those waters. Various tests were done with different amounts of calcium in the water. These mussels need calcium to survive and Tahoe has pockets that could provide habitat.
Clam shells at Lakeview Commons in South Lake Tahoe. Photo/LTN file
Quagga and zebra mussels multiply quickly, encrust watercraft and infrastructure, and compete for food with native fish. They are spread from one body of water to another attached to nearly anything that has been in an infested water body, or via standing water from an infested water body entrapped in boat engines, bilges, live-wells and buckets. That is why the boat inspection programs at Tahoe and other nearby water bodies were established.
“Our state’s natural resources are facing unprecedented threats today,” California Department of Fish and Wildlife Director Charlton Bonham said in a statement. “Preventing the spread of Quagga and zebra mussels, as well as other invasive species, is something everyone can take an active role in, thereby helping to protect the fish, wildlife and the habitats on which they depend.”
Quagga mussels were first detected in the Colorado River system in January 2007 and were later found in San Diego and Riverside counties. They are known to be in 29 waters in California, all in Southern California. Zebra mussels were discovered in San Justo Reservoir in San Benito County in January 2008.
I’ll say the same thing again and see if someone tells me I am incorrect. Not only is harvesting (mowing) water milfoil ineffective but it is absolutely counterproductive and needs to be completely prohibited. (Where is Lahanton and the TRPA?)
Every single little piece becomes a potential new colony as milfoil doesn’t need soil to proliferate. New floating masses are created by harvesting, ie. mowing it. Go try to boat or swim in Lake Minnetonka, MN and get a grip on what the future holds for the waters of Tahoe. The only fix that has a chance is walling-off the Keys and draining them until the nursery for milfoil has been killed-off.
Some years ago a company named ” solar bee” installed 5or 6 solar powered water moving devices in the TKM lagoons at various random locations choked with Eurasian millfoil,
These solar powered devices actually turned a large flat propellor type blade which drew water from the bottom of the lagoon up through an adjustable plastic tube, approx 36″ across and dispelled the water outward on the surface.
After these devices had been operating for approximately 60 days I assisted the person in charge of this demonstration with video cameras and we both observed the now barren bottom , completely free of any weeds.
Why is it that this device has disappeared into the sunset with never a mention ?????
These devices are used in numerous reservoirs back east and actually WORK.
Because of the movement of the water, the aquatic weed cannot survive.
One device was able to clear approx 5 surface acres of weeds.
Another thing never mentioned in print is the fact that when the Tahoe Keys lagoons were first excavated a large system of pumps were installed to actually circulate the water around the Keys lagoons. It was never even operated, and I believe is still in place at the intersection of T K blvd and Venice.
The basic science of all this is that the weeds choking the lagoons require stagnant or non moving water to thrive.
The solar bee devices WORKED, as I saw the results for myself.
The unused circulating pumps at the TKPOA would more than likely do the same.
FYI Steve.
cluster = tahoe keys. is there in place a financial punishment system that converts $$ from keys property owners into efforts to curb damage to the lake?
the homeowners transplanted the AIS from the channel to the beach.
because they did not want to spend the money to haul the dirt-sand away.
another prime example of Porked.
The Keys are the gift that keeps on giving. How much damage could be stopped by shutting them off from the lake and cleaning things up for just ONE season? The property owners won’t die, but if this keeps up, Lake Tahoe will.
Steve-
I cannot speak for the solar bees, although I knew of the effort. I think it did not work as well as you suggest.
The circulation system you mention was operated for many years, and may still be as far as I know. It works to keep the water in back lagoons from going stagnant and smelling etc.
The Keys operated a large water treatment system for many years at the Keys water company yard back off of Washington street or thereabouts. I think it was shut down for high costs and poor effectiveness. There is a large circular thickener/filter which has likely rusted in place.
The Keys is the death of Lake Tahoe, close off the lake access and let the lagoons return to meadow land to save our lake! The Keys was the single worst disaster to Lake Tahoe, sorry Keys homeowners, just stating a FACT!
Just out of curiosity, who owns the flooded land that constitutes the “canals” in the Keys? Do the individual property lines meet in the middle of the canals? If so, does someone hold an easement for the canals? If not, where are the property lines, and who actually owns the canals?
Has Army Corps of Engineers, which supposedly has jurisdiction over all navigable waterways (and I recall from working on the Bay Area waterfront years ago that a navigable waterway can be one on which you can float a matchstick – or was it a toothpick?) ever become involved in the Keys?
Why spend time researching when I can go on here and access experts?
And the only reason that they “harvest” or try to remove the milfoil is so that their watercraft can make it through the canals without that stuff getting caught up in propellers and intakes…it does though, and they spread it everywhere they go on the lake, I see it floating everywhere when paddle boarding. I agree with J&B, the Keys Marina and homeowners side needs to close for a season so that it can be removed…one season of closure and clean-up (that they don’t want to pay for) would be great for the lake and for all our little future generations
Aquatic invaisive species (AIS), is a real problem. This all started with the dredging of the Truckee Marsh to turn it into the Tahoe Keys development that we know today.
Eurasian Milfoil spreading thru out the lake, mussels, clams, non-native warm water fish like bass, koi and their non-natives living in our beatiful lake.
It’s too bad we can’t go back in time to have stopped this development before it ever started. What a mess!
Take care of the lake, before it’s too late.
Old Long Skiis
The Tahoe Keys was an unfortunate mistake. However, since this housing development is now a permanent fixture of the lake and the community we need to assess and approach the situation as best we can. While the Keys do provide ideal habitat for many invasive species the development is not solely to blame for AIS in Lake Tahoe. How many lakes without man made developments have been infested with plants and animals that do not belong there? Many times fragments can be introduced by boaters (including non-motorized boaters) traveling from other areas. That is why education and outreach is so important to controlling the AIS problem. The Keys has and continues to work with the the League to Save Lake Tahoe and other organizations to educate the homeowners and the community about AIS and ways to help control the problem. I encourage everyone to get out there and get informed so that together we can help keep Lake Tahoe beautiful for generations to come.
Interesting comments , the solar bee devices did exactly what they were designed to do but the TKPOA was not willing to invest in these items.
The floating lawn mowers / harvesters have done more damage by simply giving the weeds a hair cut, and in the process releasing thousands of small pieces of weed with seeds attached to circulate out into the lake.
Well don’t bother closing the barn door, because the weeds are already in the lake and have been for many years.Any fisherman will attest to reeling in lines snagged with weeds from locations all around the lake.
I think the only good part is that the lake temp is so cold that the weeds do not grow very tall or fast on the bottom.
Regarding property lines in the lagoons , the TKM property lines actually are in the lagoon and and run between the marina and the TKPOA properties.
It is Interesting that the TKM has closed the channel which is shared by TKM TKPOA and Beach and Hbr assn. thereby preventing lake access to all parties
Copper-
Most but not all single family homeowners have lot lines that extend into the lagoons to the middle or their particular channel.
Townhomes have docks but owners do not own into the water. Gang docks are provided for townhome owners.
There are public easements in place to allow other owners boats access, and actually any boater can cruise in the keys and look around on these public easements.
There are various agreements in place between the association and the Tahoe Keys Marina. The has no ownership or management by the Tahoe Keys property owners association.
Steve buttling- It’s been about 20 years since I have been sounding the alarm on Eurasian watermilfoil. What you say is ‘one good thing’ was TRPA’s mantra back then. The claims were that Tahoe’s waters are too cold for milfoil growth. Except it can and does grow in floating colonies where it is warm enough to survive- that’s everywhere on top of the water. Oh, and then there are the marinas, with low, warm water where milfoil explodes and gets dragged all over the Lake and as we all know, it’s everywhere now. How’s that cold water temperature protecting Tahoe, again, TRPA? Their mission to protect Lake Tahoe is a complete and utter failure.