Invasive species, also known as exotics, are plants, animals,
insects, and aquatic species introduced into non-native habitats.
Without natural predators or threats, these introduced species
then multiply.
Often,invasive species travel to non-native areas by ship,
either in ballast water released into harbors or attached to the
sides of boats. From there, introduced species can then spread
and significantly alter ecosystems and the natural food chain as
they go. Another example of non-native species introduction
is the dumping of aquarium fish into waterways.
Invasive species also put water conveyance systems at risk. Water
pumps and other infrastructure can potentially shut down due to
large numbers of invasive species.
The Westside Water Authority, at its March 11 meeting, got an
idea of how much it will likely cost to combat the golden
mussel invasion – at least $3.8 million. And that’s just
the start. The authority is composed of Belridge Water Storage
District, Lost Hills Water District, Berrenda Mesa Water
District, and Dudley Ridge Water District. Belridge first
detected the mussels in its facilities in October 2025. The
mollusks have since spread throughout all four districts on
Kern County’s western edge. … If authority member
districts agree to use GreenLeaf Ag, it would employ the
chemical EarthTecQZ. … Even at lower doses, the chemical
could potentially affect carp but not game fish.
As invasive mussel species continue to spread across the state,
both local and national agencies, such as the US Bureau of
Reclamation (BOR), are exploring every avenue to stop them.
Now, they’re offering up some serious money for the right idea
to help stop the spread of these shellfish. The three-phase
‘Halt the Hitchhiker’ program is offering up $200,000 for the
winning proposal, with cash prizes offered at each phase for
winning ideas. The push stems from continued concern about
invasive shellfish such as the Quagga, Zebra and more recent
Golden Mussels.
Even though golden mussels were only detected in California in
October 2024, they pose a significant and immediate threat to
the state’s waterways. … Unfortunately, many of the common
inspection programs and methods—like boat inspections or
eDNA—can be costly, labor intensive, and slow. While these
methods offer comprehensive results, the rapid spread of golden
mussels requires tools that deliver immediate answers as
boaters enter waterways. Luckily, a new solution is on the
rise: dogs that can smell invasive species. From time on the
treadmill to weekly weigh-ins, golden mussel-sniffing dogs are
treated like star athletes at Mussel Dogs, an Oakdale-based
canine training and environmental consulting business.
Wildlife officials are just weeks away from turning the water
on at the Lake Mead Fish Hatchery, a facility that had to
abandon raising trout as water levels dropped at the nation’s
largest reservoir. Now, the hatchery is refitted to bolster
numbers of two endangered fish native in the Colorado River —
the “rarest of the rare” bonytail chub, and the razorback
sucker. … When water levels plummeted in 2022, the pipe
that supplied water to the hatchery went dry, but problems at
the hatchery started long before that. … In early 2007, an
invasive species that spreads quickly and damages natural
habitats was found in Lake Mead and lower areas of the Colorado
River. That meant trout from the hatchery couldn’t be stocked
anywhere outside those areas to eliminate the risk of
introducing quagga mussels.
Colorado Parks and Wildlife is launching an awareness campaign
called “Oh Shell No” to address the spread of zebra mussels in
the state, with a focus on impacts to agriculture and water
infrastructure. In 2025, CPW detected adult zebra mussels in
the Colorado River for the first time, as well as in smaller
lakes and ponds in the Grand Junction area. … As
temperatures rise, CPW plans to put more technicians in the
field for sampling. The agency said it will focus monitoring
efforts upstream of areas where zebra mussels have already been
found.
Destructive, tiny golden mussels that hitched
their way across the ocean into the Sacramento-San
Joaquin Delta about two years ago are likely here to
stay, according to panelists at this year’s annual Kern County
Water Summit. And, so far, no eradication, or even effective
treatment, method has been discovered to keep the invasive
mollusks from clogging up equipment and pipes in the state’s
vast water delivery networks. … Water managers in Kern
were dismayed to find the mussels had made their way from the
delta into local water systems all the way to Arvin last
November. And getting them out of the delta … will likely
prove impossible.
A tiny mollusk, native to China and southeast Asia, made its
way to California in 2024. Its potentially disruptive effects
to water systems are now in Kern County. The golden
mussel threatens to disrupt California’s surface water
delivery system, from the Sacramento San Joaquin River Delta
all the way to farms in Kern County. This week the Water
Association of Kern County is holding its annual Water Summit
and that tiny mollusk is becoming a bigger focus at this year’s
event. The golden mollusk, by all accounts, is a prodigious
progenitor colonizing beneath the water’s surface and anchoring
itself to just about anything it can latch on to.
Beginning this month, the Wyoming Game and Fish Department will
resume seasonal operations for aquatic invasive species check
stations across Wyoming. These mandatory stations help ensure
watercraft are not bringing invasive species of mussels into
the state’s waterways. “Wyoming is one of few places in the
country that hasn’t detected invasive zebra or quagga mussels
in the water,” Game and Fish AIS Coordinator Josh Leonard said.
“Our agency is working to keep it that way, and make sure these
destructive species stay out of the state’s
waters.” Leonard said any out-of-state boater, as well as
Wyoming residents who have taken their watercraft outside the
state, need to go through the inspection checkpoints.
Aquatic invasive mussels that can hitch a ride in a small
amount of trapped water are prompting a new competition aimed
at stopping their spread — and it comes with significant prize
money. The U.S. Bureau of Reclamation announced the “Halt the
Hitchhiker: Invasive Species Challenge,” a three-phase prize
competition designed to identify innovative solutions that stop
aquatic invasive species from spreading through watercraft
ballast compartments. Aquatic invasive species such as
quagga, zebra, and golden mussels can travel between
waterbodies in small amounts of water trapped in ballast
systems. The invasive mussels threaten water delivery and
hydropower infrastructure across the West.
California State Parks’ Division of Boating and Waterways (DBW)
today announced the availability of grant funding to help
prevent the further spread of quagga and zebra mussels that
threaten California’s waterways and cause negative impacts to
recreational boating, fishing and the ecosystem. Funded by the
California Mussel Fee Sticker (also known as the Quagga
Sticker), the Quagga and Zebra (QZ) Mussel Infestation
Prevention Grant Program expects to award up to $2 million
across eligible applicants. Applications open Monday, March 9,
and must be received by Friday, April 17, 2026, by 5 p.m. PDT.
Following the discovery of invasive zebra mussels in the
Colorado River last year, Colorado Parks and Wildlife (CPW) is
working hard to prevent further contamination across the
state. Part of that is an ongoing effort in boat
inspections to prevent the spread of invasive aquatic species
including both zebra and quagga mussels. In 2025, CPW conducted
more than 438,000 such inspections at various bodies of water.
Officials say early detection of the invasive species was made
possible by increased staffing and upgraded lab facilities, but
the discovery on the Western Slope still set off alarm bells
because once adults are present in a reproductive state, they
have the ability to rapidly multiply and clog
infrastructure.
In the cool dawn of a February morning, a crew is assembling to
do maintenance work on a water canal in Tempe. This crew will
spend the rest of its life in the canal, removing the plants
that stop water from flowing. That’s because the workers aren’t
human — they’re fish. The Salt River Project, which operates
this canal, estimates that about 44,000 of these fish live in
its canal system. This morning, it’s adding about 1,000 more.
The fish are a species of carp called white amur. They’re
native to Asia and especially adept at eating the aquatic
vegetation that grows along the walls of the canal. Those
plants can slow down the water and make it harder to send to
faraway users of the canal or gum up the intakes that divert
water in different directions.
Officials are sounding the alarm over an invasive species
threatening one of California’s key water systems. Golden
mussels, first detected in the Friant-Kern Canal two months
ago, are rapidly multiplying and could disrupt water delivery
to farms and communities in the southern San Joaquin Valley.
The Friant Water Authority held a board meeting Thursday to
address the infestation and outline next steps. The board voted
to hire a consultant to develop a comprehensive control plan,
though any treatment would require permits and could take
several months. The agency is also seeking grants to help fund
prevention and control efforts.
Colorado Parks and Wildlife staff conducted more than 438,000
watercraft inspections in 2025 to prevent the spread of
invasive species in state waters. The agency decontaminated
more than 30,000 high-risk boats and intercepted 136 vessels
carrying invasive mussels during the year-long effort. The
inspections are part of a statewide prevention program designed
to protect water infrastructure from destructive aquatic
nuisance species. … In 2026, staff will install a
decontamination dip tank at Highline Lake to reduce wait times
for departing boaters. The agency also plans to partner with
federal and local groups to sample Grand Valley ponds and lakes
that receive water from the Colorado River.
The Arvin-Edison Water Storage District and Wheeler
Ridge-Maricopa Water Storage District boards both agreed
recently to spend $2.5 million and $2 million, respectively, on
efforts to rid their systems of invasive golden
mussels. At its Feb. 10 meeting, Arvin-Edison’s Resource
Manager Samuel Blue laid out a two-phase attack against the
mussels. First, Blue plans to start with a chemical treatment
called Natrix CA in March, when there is less water demand by
district farmers and the temperatures are cooler. The mussels
are more active in warmer water, Blue explained. He hoped the
treatment would kill off 90%, or more, of the adult golden
mussels.
The time to act on golden mussels is yesterday. If not
yesterday, then now, an expert on invasive mollusks told
attendees at the World Ag Expo in Tulare Wednesday. … These
things are “quagga mussel on steroids” said David Hammond, a
senior scientist at Earth Science Labs. He urged irrigation and
water district managers at the seminar to enact immediate
preventative measures, or their entire conveyance systems would
be at risk of being overrun by the tiny, rapidly multiplying
mussels. … Golden mussels, native to Southeast Asia and
a cousin to quagga and zebra mussels, were first discovered in
the Sacramento-San Joaquin Delta in 2024. And in less than a
year, have traveled the length of the state, clogging
infrastructure as they rapidly multiply.
When the golden mussel was discovered near the Port of Stockton
in late 2024, lakes and reservoirs across Northern California
imposed new rules on boaters to try to keep the invasive
species out. EBMUD, the water supplier for most of the East
Bay, took no chances, banning all boats from entering its
reservoirs. On Sunday, after more than a year, they began
inviting boats back to the water, but they’re being very
careful about it. … EBMUD has decided the most effective
action is a 30-day quarantine. After an inspection to be
sure they’re completely clean and dry, boats will be tethered
to their trailers with sealed cables to prevent them from being
launched. After the waiting period, they will be allowed back
on the lake and then, upon leaving, given another sealed
tether, specific to San Pablo.
If the golden mussel invasion that already is
expanding throughout much of California hits the Eastern
Sierra, the damage it will bring will ripple far beyond
recreational fishing, according to state officials. Nick
Buckmaster, an environmental specialist with the California
Department of Fish and Wildlife, told the Inyo County Board of
Supervisors Tuesday that the invasive species is “amazingly”
resilient and that its adaptability makes it effectively
impossible to eradicate.
The 24-page Layperson’s Guide to the Delta explores the competing
uses and demands on California’s Sacramento-San Joaquin
Delta. The 11th edition examines this critical
water hub and its myriad challenges. The 2025 version
includes the latest information on the tunnel project, habitat
restoration efforts, climate change impacts and an updated
section on the legal and political facets of the Delta.
A new aquatic invader, the golden mussel, has penetrated California’s ecologically fragile Sacramento-San Joaquin Delta, the West Coast’s largest tidal estuary and the hub of the state’s vast water export system. While state officials say they’re working to keep this latest invasive species in check, they concede it may be a nearly impossible task: The golden mussel is in the Golden State to stay – and it is likely to spread.
In the vast labyrinth of the West
Coast’s largest freshwater tidal estuary, one native fish species
has never been so rare. Once uncountably numerous, the Delta
smelt was placed on state and federal endangered species lists in
1993, stopped appearing in most annual sampling surveys in 2016,
and is now, for all practical purposes, extinct in the wild. At
least, it was.
This tour guided participants on a virtual journey deep into California’s most crucial water and ecological resource – the Sacramento-San Joaquin Delta. The 720,000-acre network of islands and canals support the state’s two major water systems – the State Water Project and the Central Valley Project. The Delta and the connecting San Francisco Bay form the largest freshwater tidal estuary of its kind on the West coast.
Nutria are large, beaver-like
rodents native to South America that have caused alarm in
California since their rediscovery along Central Valley rivers
and other waterways in 2017.
The growing leadership of women in water. The Colorado River’s persistent drought and efforts to sign off on a plan to avert worse shortfalls of water from the river. And in California’s Central Valley, promising solutions to vexing water resource challenges.
These were among the topics that Western Water news explored in 2018.
We’re already planning a full slate of stories for 2019. You can sign up here to be alerted when new stories are published. In the meantime, take a look at what we dove into in 2018:
Sixty percent of California’s developed water supply
originates high in the Sierra Nevada mountains. Our water
supply is largely dependent on the health of our Sierra forests,
which are suffering from ecosystem degradation, drought,
wildfires and widespread tree mortality.
We headed into the foothills and the mountains to examine
water issues that happen upstream but have dramatic impacts
downstream and throughout the state.
GEI (Tour Starting Point)
2868 Prospect Park Dr.
Rancho Cordova, CA 95670.
For more than 100 years, invasive
species have made the Sacramento-San Joaquin Delta their home,
disrupting the ecosystem and costing millions of dollars annually
in remediation.
The latest invader is the nutria, a large rodent native to South
America that causes concern because of its propensity to devour
every bit of vegetation in sight and destabilize levees by
burrowing into them. Wildlife officials are trapping the animal
and trying to learn the extent of its infestation.
Estuaries are places where fresh and
salt water mix, usually at the point where a river enters the
ocean. They form highly productive natural habitats due to a
combination of tides, waves, salinity, fresh water flow and
sediment.
A troublesome invasive species is
the quagga mussel, a tiny freshwater mollusk that attaches itself
to water utility infrastructure and reproduces at a rapid rate,
causing damage to pipes and pumps.
First found in the Great Lakes in 1988 (dumped with ballast water
from overseas ships), the quagga mussel along with the zebra
mussel are native to the rivers and lakes of eastern Europe and
western Asia, including the Black, Caspian and Azov Seas and the
Dneiper River drainage of Ukraine and Ponto-Caspian
Sea.
This 24×36 inch poster, suitable for framing, explains how
non-native invasive animals can alter the natural ecosystem,
leading to the demise of native animals. “Unwelcome Visitors”
features photos and information on four such species – including
the zerbra mussel – and explains the environmental and economic
threats posed by these species.
This 24×36 inch poster, suitable for framing, explains how
non-native invasive plants can alter the natural ecosystem,
leading to the demise of native plants and animals. “Space
Invaders” features photos and information on six non-native
plants that have caused widespread problems in the Bay-Delta
Estuary and elsewhere.
