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 East Bay Regional Park District (EBRPD) announces changes
to its boat inspection and banding policies effective May 7,
2025, in response to increasing concerns about invasive mussel
species. EBRPD has long required watercraft inspections to
prevent the spread of aquatic invasive species into local lakes
and reservoirs. To simplify re-entry for frequent visitors,
park staff have used tamper-proof bands placed between the
watercraft and trailer when the boat leaves the lake. These
bands serve as proof that the vessel hadn’t launched in other
waters. Boats returning with an intact band have not required
re-inspection when entering any lake in the Park District or
the East Bay Municipal Utility District (EBMUD). What’s
new for summer 2025 is that EBRPD’s banding program is
transitioning to color-coded, lake-specific bands and is no
longer accepting EBMUD bands, effective May 7.
The state of California has adopted a new framework to
coordinate a response to the recent discovery of golden
mussels, an invasive species that can wreak havoc on local
ecosystems. … In December 2024, the California Fish and
Game Commission voted to list golden mussels as a restricted
species. To help contain and suppress the invasive shellfish,
the California state government has unveiled a comprehensive
Golden Mussel Response Framework. … Among the measures
called for in the framework are an investigation into how
golden mussels can spread, increased inspection and
decontamination of watercraft, and an education campaign.
California wildlife officials detected an invasive species in
the Sacramento-San Joaquin Delta that threatens numerous
ecosystems in the northern part of the state. On April 16,
officials announced the Golden Mussel Task Force, a statewide
interagency group aimed at curbing the spread of the invasive
species. Agencies include the California Department of Fish and
Wildlife, California State Parks, and the California Department
of Food and Agriculture. Here’s what you need to know about
Golden Mussels.
Last October, an invasive species never before seen in
North America was discovered in the deep waters of the
Port of Stockton, about 92 miles east of San Francisco. No
larger than the size of a paperclip, the seemingly innocuous,
caramel-colored shells of golden mussels clinging to buoys and
monitoring equipment in the Sacramento-San Joaquin Delta — and
subsequently found at O’Neill Forebay in the San Luis Reservoir
near Los Banos — have left California officials scrambling to
stop the spread. On Wednesday, the California Department
of Fish and Wildlife released its plan to address
what it’s calling an “urgent invasive species threat,” with
strategies to prevent further distribution of golden mussels
and to minimize their impact on the environment, recreation,
agriculture and, notably, drinking water infrastructure.
The State of California is taking significant steps to combat
the recent discovery of golden mussels in the Sacramento-San
Joaquin Delta. According to officials, this marks the first
occurrence of the invasive species in North America. The
California Department of Fish and Wildlife (CDFW) is leading
the charge, offering $1 million in grants to boating facility
operators. These funds aim to enhance efforts against invasive
mussels in the state’s lakes, reservoirs, and waterways. The
golden mussel, native to East and Southeast Asia, poses a
severe threat to California’s ecosystems and infrastructure.
Minutes before sunrise Monday, nearly a dozen boat owners were
already lining up in the Beals Point parking area for the first
day of boat inspections and a 30-day quarantine aimed at
preventing an invasive species from finding its way into Folsom
Lake. “It’s long before the scheduled 9:30 a.m. start time for
inspections, but I’m glad I got here early,” said Rudy Divin, a
fishing guide. Starting Monday, Folsom Lake and Lake Clementine
are closed to all motorized and trailered vessels for the next
month. All boats seeking to launch on either lake are required
to go through a mandatory 30-day quarantine.
Since golden mussels were recently identified in the
Sacramento-San Joaquin Delta, officials introduced new rules
for boaters at some waterways in parts of Northern California
and the Bay Area. … Federal and California state officials
announced Monday a set of new inspection and quarantine
requirements for the launch of boats at Folsom Lake and Lake
Clementine. Those will take effect starting April 14. This
comes after other new restrictions have been put in place at
Rancho Seco Lake, Woodward Reservoir and Lake Berryessa, among
other water bodies. The state maintains a list of where
watercraft inspections are required for certain vessels to
combat the spread of golden mussels, zebra mussels and quagga
mussels. Because the list may not have the latest information,
boaters are urged to contact the agency that manages the water
body they plan to visit. See more in the map below.
Whiskeytown National Recreation Area rangers are cautioning
anglers and boaters to clean their equipment and crafts (small
and large) before taking them to Whiskeytown Lake and other
Shasta County waters. They and California Department of Fish
and Wildlife officials are trying to stop golden mussels from
invading North State waters after the animals first arrived for
the first time in Northern California last October. The tiny
fresh and brackish water mollusk could spell big trouble for
California reservoirs, clogging pipes, they said; and could
potentially devastate Whiskeytown Lake’s other freshwater
bodies’ ecosystems. The state recently began to require
inspections of boats at Folsom Lake and Lake Clementine in the
Sacramento area to stop the invasive species from spreading.
East Bay Municipal Utility District (EBMUD) is keeping boat
launches closed for the 2025 season at three of its reservoirs
in an effort to prevent the spread of golden mussels.
Earlier this year, EBMUD closed boat access to the Pardee and
Camanche reservoirs, both located in the Sierra foothills,
until further notice. In an update on Wednesday, EBMUD
announced the boat launches at the two reservoirs, along with
the San Pablo Reservoir in the East Bay, will remain closed
throughout the 2025 season. … Others, like Folsom Lake
above Sacramento, are requiring that all boats be cleaned,
inspected and quarantined for 30 days on the premises before
they can be launched. … EBMUD isn’t taking any chances. The
primary purpose of their reservoirs is as a water supply, and
they aren’t going to jeopardize their infrastructure in the
name of recreation.
Faced with the rapid spread of golden mussels across California
waterways, state and federal officials are imposing strict new
measures at Folsom Lake and Lake Clementine to prevent the
invasive species from taking hold. Beginning Monday, all
trailered or motorized boats at the two popular Sacramento-area
lakes will be required to undergo inspection and a mandatory
30-day quarantine before launching. Golden mussels, native
to Asia, were first detected in California waters last fall in
the Port of Stockton. Since then, they have spread rapidly
through connected waterways, reaching as far south as
Bakersfield. Officials warn that the freshwater mollusks
threaten California’s water infrastructure, power systems and
aquatic ecosystems by clogging pipes, outcompeting native
species and damaging boats by attaching to hulls and clogging
engines.
Federal and California state officials announced Monday a set
of new inspection and quarantine requirements for the launch of
boats at Folsom Lake and Lake Clementine later this month. The
rules are aimed at preventing an infestation of golden mussels,
which were recently identified in the Sacramento-San Joaquin
Delta and that “pose a significant threat to the ecological
health of all waters of the state, its water conveyance
systems, infrastructure, and water quality,” California State
Parks said. Folsom Lake and Lake Clementine in the Auburn
State Recreation Area will be temporarily closed to all
trailered or motorized vessel launching for a month, from April
14 until May 14.
The headgates are open and water is returning to Highline Lake
in the state park located outside of Grand Junction
(Colo.). The lake — fed by the Government Highline Canal
and connected to the Colorado River — was
drained in November after a years-long battle against invasive
zebra mussels. Colorado Parks and Wildlife announced that it
began refilling the lake on March 31. The first adult
zebra mussel was found in the lake in 2022, marking the first
discovery of the species in Colorado water. After finding more
mussels, Colorado Parks and Wildlife launched a response that
included applying molluscicide to the lake, water sampling,
cleanup efforts and ultimately, draining the lake entirely.
This was the first time the lake was fully emptied in 60
years.
A recreational area in southeastern Sacramento County is
implementing new restrictions to protect its popular lake. It’s
happening at Rancho Seco, in the town of Herald. New watercraft
restrictions are now in effect to stop the spread of golden
mussels recently discovered in the Sacramento-San Joaquin
Delta. Signs around Rancho Seco alert people to the invasive
species, saying, “Don’t move a Mussel.” No trailer-launched
boats are allowed on the lake. People can still use small
watercraft like canoes, kayaks, paddle boats, and smaller
electric watercraft, but only if they haven’t been used in
other waterways, including the Delta, within 30 days.
The Solano County Water Agency’s free vessel decontamination
program will end on April 7. … The Bureau of Reclamation
announced that, beginning April 7, direct-managed concessions
and the Solano County Water Agency will charge for vessel
decontaminations for boaters seeking to launch at Lake
Berryessa. … “Moving forward, boaters who seek to avoid a
30-day, mandatory quarantine to protect the reservoir
from invasive mussels, will need to reach out to
either the Solano County Water Agency, Markley Cove Resort,
Pleasure Cove Marina, or Putah Canyon Recreation Area to
arrange for a vessel decontamination for any motorized vessel
or vessel launched from a trailer,” the Bureau of Reclamation
announcement states.
California’s most-destructive and least-welcome swamp rodents
have arrived in its fifth-largest city. To be precise, they’ve
arrived in the stretch of San Joaquin River that traces
Fresno’s northwest border. Eight years have passed since a
reproducing population of nutria was found in western Merced
County — their first discovery in the state since the 1970s.
Despite eradication efforts that began in March 2018, nutria
have since spread north into the Delta, east into foothills
along the Merced River and south into the Fresno Slough and
Mendota Wildlife Area. … Since 2023 more nutria have been
taken from Fresno County than any county in California,
according to CDFW data. In the overall tally of 5,493 animals
that dates to 2018, Fresno County (1,140) trails only Merced
County (2,593). -Written by Fresno Bee columnist Marek Warszawski.
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.
