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.
… [F]or wetland biologists and others with a stake in the
health of the surrounding Sacramento-San Joaquin Delta, the
largest estuary on the West Coast, the birds represent the
latest – and an exponentially growing – threat to the few
remaining wetlands left in California. … Mute swans
also feed gluttonously on submerged vegetation, destroying the
plant life on which other native wetland species depend. … A
measure before the state Legislature aims to allow hunters and
landowners to shoot the swans for the next five years to try to
bring their numbers down to more manageable levels in the
Sacramento-San Joaquin Delta and beyond.
A few strands of thin, feathery, green plants growing under the
dock didn’t catch anyone’s attention last spring. But those
strands spread quickly and within months the lake’s calm waters
were tangled in mats of the feathery Eurasian watermilfoil, an
aggressive aquatic plant that grows quickly and clogs
everything in its path. … This isn’t just an isolated
incident; it’s happening across California. Aquatic invasive
species are spreading faster than ever, infesting our ponds,
creeks, reservoirs, lakes, and rivers. Now is the time to learn
about aquatic invasive species; what they are, how they spread,
and what we can do to stop them. When we understand the issue,
we can make smart choices and protect California’s waters.
Several Colorado Democrats are using the recent detections of
zebra mussels in the Colorado River to push for implementation
of key provisions in the Expanding Public Lands Outdoor
Recreation Experiences Act. The EXPLORE Act, as it’s more
commonly known, passed in December 2024 and contained multiple
bills around improving public land access and conservation,
including the aptly named “Stop the Spread of Invasive Mussels
Act.” The law gave new authorities to the U.S. Department
of the Interior and U.S. Department of Agriculture to respond
to and monitor aquatic invasive species.
… American bullfrogs are not native to the Western US. Humans
brought them to the region more than a century ago, largely as
a food source. And in the years since, the frogs — which are
forest green and the size of a small house cat — have
multiplied dramatically. … They escaped from farms and, with
other accidental and intentional introductions, proliferated
until they were common in ponds, lakes, and other water bodies
throughout much of the West, including Arizona, California, and
the Pacific Northwest. … While western states have rivers and
wetlands, permanent warm waterbodies weren’t common until the
spread of agriculture and the need for irrigation. … Now
ponds, reservoirs, and canals — which bullfrogs love — are
everywhere.
With golden mussels now confirmed
in California waterways, the focus has shifted from
detection to defense. On Monday, local leaders toured the Port
of Stockton—where the invasive species was first spotted in
North America just 10 months ago—to highlight the growing
efforts to stop the mussels before they cause widespread damage
to critical water infrastructure. … [Rep. Josh] Harder and
other California Democrats are backing a $15 million bill in
Congress to create a task force that would research, prevent,
control and eradicate golden mussels. The bill is currently in
committee. Meanwhile, scientists at a Davis-based lab are
already testing a potential biological solution.
Colorado Parks and Wildlife (CPW) has announced a plan to
contain and treat invasive zebra mussels in a privately owned
body of water in western Eagle County. According to a press
release from CPW, staff will apply EarthTec QZ, an
EPA-registered copper-based molluscicide, to the lake in the
coming weeks. Staff will routinely monitor the water to
evaluate its effectiveness following the initial treatment.
… As well as this planned treatment, CPW staff will
continue increased sampling efforts on the Colorado River and
its tributaries above and below the infested body of water.
State officials may have solved the puzzle of how zebra mussels
got into the Colorado River. On July 3, Colorado Parks and
Wildlife officials discovered a large number of adult zebra
mussels in a privately owned body of water in western Eagle
County. On Monday, Madeline Baker, an invasive species
specialist with CPW, told members of the Colorado Basin
Roundtable they believe this private lake is an upstream source
of the mussels that have contaminated the Colorado River, the
Government Highline Canal, Highline Lake and Mack Mesa Lake.
… Baker said that the lake’s owner is collaborating with
CPW on a mitigation plan. … Zebra mussels are a prolific
invasive species that if left unchecked could clog irrigation
infrastructure, and strip the plankton and nutrients from the
water.
At the Skinner Fish Facility near Byron, water for 27 million
Californians and hundreds of thousands of acres of farmland
passes through. … Early this year, golden mussels began
clogging the system. … Pam Marrone, cofounder of the Invasive
Species Corporation, has studied invasive species extensively.
Earlier this year, she was inducted into the National Inventors
Hall of Fame. … Already, she’s created a product that kills
Quagga and Zebra mussels. Zequanox is being used across the
country. In the last few months, her team has been
experimenting with Zequanox and found it can kill golden
mussels, but not at as high a rate as they would like.
… She said golden mussels are much tougher to kill than
Quagga and Zebra mussels.
… Beginning in 2008, boats trailered to Tahoe have been
required to undergo inspections for prolific quagga mussels,
which have caused vast damage in the Great Lakes, Lake Mead and
other places. But the discovery late last year of another
species, the golden mussel, in the
Sacramento River Delta has redoubled concern.
The golden mussels, native to Asia, are even heartier and more
prolific than their quagga cousins. The tiny creatures grow up
to 2 inches in length, and have already proved their ability to
spread. They have been detected in Quail Lake
in Los Angeles County. And inspectors at Alpine Meadows found a
single live golden mussel on the drive shaft of a boat bound
for Tahoe at the end of May. Allowed to proliferate, the
mussels will thoroughly encrust docks, boats and other hard
surfaces, requiring cleanups that easily run into millions of
dollars.
Water managers and state wildlife officials last year hoped the
discovery of a microscopic zebra mussel larva in the Colorado
River was a one-time event, not a sign of a larger problem
lurking beneath the surface. It was the first time larvae from
the destructive invasive species had been found in the river in
Colorado. For nearly a year, despite increased sampling, state
wildlife officials didn’t see any more evidence of the mussels.
But their hopes were dashed earlier this month when Colorado
Parks and Wildlife detected three more tiny larvae in the
stretch of the Colorado River between Glenwood Springs and
Silt. The mussels — known to devastate ecosystems and clog
critical infrastructure — had once again found their
way to the river that is the backbone of Colorado and the
Southwest’s water supply.
The Eel River Pikeminnow Fishing Derby is back again, after
over 500 fish were caught in the 2024 derby. The derby is put
on by a collaboration of groups working to restore native
fishes in the Eel River. From now through August 31st, anyone
with a fishing license (or if under 16 years of age, no license
is necessary) can go and catch pikeminnow on the Eel for a
chance to win up to $500, with $2,500 in cash prizes! There is
no entry fee. Data from your catches can help managers aid in
the conservation of our native fishes. Pikeminnow were
introduced to the Eel River via Pillsbury Reservoir in the late
1970’s. Since then, they have spread to all the forks of the
Eel and are remarkably prolific. … The waters open to
fishing for the derby are: the South Fork Eel River downstream
of the Humboldt County line to the confluence with the
mainstem, the mainstem Eel from Dos Rios to the mouth of the
Van Duzen, and the Van Duzen from Grizzly Creek to the mouth of
the Van Duzen.
One of the state’s best investigators was on the hunt for
golden mussels — a dangerous new invader in
California’s waters, with a reputation for destruction.
Wearing a collar and a tongue-lolling grin, Allee, a Belgian
Malinois, sniffed along the glittering hull of a bass boat at
an inspection station in Butte County. … The dog was
searching for any hint of the thimble-sized mussels hidden in
the nooks and crannies of boats headed to Lake
Oroville, the state’s second-largest reservoir, or two
smaller reservoirs nearby. … State water managers made the
alarming discovery last October that golden mussels, which are
native to China and Southeast Asia, had invaded the
Sacramento-San Joaquin River Delta — the
core of California’s massive water delivery
systems. … Now the mussels are here to stay. They
cannot be eradicated. Water suppliers bracing for the onslaught
have instead turned their efforts to shoring up pipes, pumps
and treatment plants against the infestation.
The Colorado River is now officially “positive” for invasive
zebra mussels in the latest failure of containment for the
voracious species, after three new samples came up with larvae
July 3, from between Glenwood Springs and Silt. The main stem
Colorado River discoveries piled on top of a confirmed “large
number” of adult zebra mussels in a private body of water in
western Eagle County, and two more positive larvae tests, at
Highline Lake and Mack Mesa Lake, both near the Utah border,
Colorado Parks and Wildlife officials said Wednesday. Sampling
was redoubled throughout June after tests found a single zebra
mussel larvae, or veliger, in the Colorado River from a June 9
collection. It’s the second year in a row veligers are
being discovered in the West’s key river channel through
Colorado, and now CPW officials are also dealing with a
full-blown adult zebra mussel invasion in the privately owned
Eagle County water.
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 are the meeting point between riverine environments
and the sea, with a combination of tides, waves, salinity, fresh
water flow and sediment. The constant churning means there are
elevated levels of nutrients, making estuaries highly productive
natural habitats.
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.
The 24-page Layperson’s Guide to the Delta explores the competing
uses and demands on California’s Sacramento-San Joaquin Delta.
Included in the guide are sections on the history of the Delta,
its role in the state’s water system, and its many complex issues
with sections on water quality, levees, salinity and agricultural
drainage, fish and wildlife, and water distribution.
