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Recent accomplishments of CDFW's scientific community


Enhancement Projects Weed Out Invasives in Marin County

Enhancement Projects Weed Out Invasives in Marin County

an orange butterfly with black spots stands on a yellow flower, amid green and purple succulents
Native to the California coast and the California/Nevada state line, the Myrtle’s silverspot butterfly feeds on the nectar of the monardella flowers.

a tiny shorebird with a light brown coat, black beak, and white underside, standing on wet beach sand
One of 33 species of birds listed as threatened or endangered by the State of California or the federal government, the western snowy plover is in jeopardy of disappearing from the dunes.

patches of green vegetation live on a coastal ridge full of dead, beige beach-grass
in 2017, two years after treatment, the southwest side of the herbicide treatment area shows little regrowth of invasive plants.

Sandy dunes along the California coast often feature hardy European beachgrass and a succulent, freeway iceplant, that many assume is part of the native flora. However, these groundcover plants were originally introduced in the 1800s by Gold Rush settlers who were hoping to keep sand from moving to the nearby roads, railroads and land. Today, they are invasive species that out-compete the native plants and the animals that live there.

Over the years, the invasives took over the native Tidestrom lupine and beach layia, causing them to be placed on the federally endangered species list. The endangered Myrtle’s silverspot butterfly and the threatened snowy plover are dependent on native plants like these, and today, they too are in jeopardy of disappearing from the area.

“Snowy plovers naturally select open areas to nest so that they can more easily spot predators,” said CDFW Environmental Scientist Laird Henkel. “The European beachgrass spreads quickly making the dunes less desirable as a place for these birds to nest.”

Scientists determined that removing these invasive plants would be the best way to restore the dunes and the ecosystem that depends on them. To this end, CDFW awarded $54,000 in Environmental Enhancement funds to a project on the Point Reyes North Great Beach, located in Marin County, to restore the native sand dune plants on a 13-acre area in 2015. The fund committee selected the Point Reyes application because of the success of their previous dune restoration projects.

Point Reyes National Seashore staff oversaw the removal of the invasive plants on the dunes. Their contractors spray-treated the dunes with an herbicide and uprooted the invasives by hand; they worked during times of low winds and no rain, to protect other natural plants, wildlife, nearby farms and the public from overspray.

Point Reyes scientists monitored the treated area with an easy-to-use mapping tool called photo point monitoring – an effective method of monitoring vegetation and ecosystem change. Visual surveys and the mapping program showed just a one-to-three percent regrowth of the invasive plants over time, while previous restoration projects showed much more regrowth.

“The project area represents a vital link between earlier restoration efforts near Abbotts Lagoon and new restoration efforts at the AT&T cell tower area, enabling the park to move closer towards its goal of several miles of dune habitat not wiped out by invasive plants such as European beachgrass and iceplant,” said Point Reyes National Seashore Ecologist Lorraine Parsons.

CDFW-OSPR and the Point Reyes staff consider the project’s first objective – eradicating invasive European beachgrass and ice plant – a success. Earlier this year, scientists noticed in treated areas the reappearance of wild cucumber. The reappearance of other native plants such as the mock heather, California blackberry and yarrow, and wildlife is the second objective, the success of which will be determined over time. Other treated areas in the region show beachgrass breakdown and increased native dune scrub and mat species after six years.

Photos courtesy of Point Reyes National Seashore and the U.S. Fish and Wildlife Service.

Top photo: The Point Reyes National Seashore staff oversee contractors spray-treating the dunes with an herbicide.


Stacking the Odds to Stock California’s Waters

Stacking the Odds to Stock California’s Waters

Three men brush a white epoxy on a 600-foot-long by 5-foot wide concrete channel
Working late, Mojave River hatchery staff apply FDA-certified epoxy coating to hatchery rearing ponds.

a tank truck parked next to a concrete fish hatchery raceway with palm trees in background
CDFW fish transportation truck at Fillmore Hatchery

An African American man in a California Fish and Wildlife uniform squats to read something on a low concrete wall at a fish hatchery
Acting Mojave River Hatchery Manager Forest Williams at work

Seven people watch fish come out of a 10-foot pipe from a CDFW tank truck, into a root beer-colored river
A hatchery crew releases trout into the Feather River

view from river-level of water and fish pouring from a tank truck, through a pipe
A fishy view of trout planting on the Feather River

The beginning of trout fishing season in Southern California is just around the corner, and CDFW biologists and hatchery staff are striving to maximize hatchery trout availability for the many anglers who will cast lines in coming weeks. Trout angling in lower-elevation waters of Southern California generally begins in November and continues through April, to correspond with colder water temperatures that can sustain stocked trout.

Precise temperatures are just one of the criteria that must be met before trout stocking begins. Currently, these conditions are approaching optimal levels, but CDFW is running about two weeks behind schedule due to unforeseen circumstances at Mojave River and Fillmore trout hatcheries, two of CDFW’s southernmost facilities.

The Mojave River Hatchery, built in 1947, raises and stocks a ten-year average of 340,000 pounds of catchable trout per year. Beginning in June of this year, extensive maintenance and facility upgrades necessitated turning off the water for a six-month period. While the completed upgrades will ultimately result in better and more efficient trout production for Southern California, the project ran about two months behind schedule. Water is scheduled to flow again at Mojave River Hatchery in late November and the hatchery will be populated with fingerling trout for fast growth. Mojave’s year-round water temperatures yield fast trout growth resulting in maximized yield in minimal time.

While the Mojave River Hatchery was closed, Fillmore Hatchery, built in 1941 on the Santa Clara River, experienced a significant loss of trout inventory intended for Southern California angling due to gas bubble disease. Gas bubble disease is a result of supersaturated gasses (oxygen, nitrogen and carbon dioxide) present in well water pumped from a deep aquifer. While Fillmore Hatchery is equipped to aerate this water and make it suitable for trout, an unknown variable (possibly a drought-depleted and then recharged aquifer) overwhelmed that ability. In an average year, Fillmore Hatchery produces about 400,000 trout for lakes and streams in Southern California. To reduce fish losses from gas bubble disease in the last several weeks, catchable fish were stocked from Fillmore to appropriate waters, and some fish were transferred to other hatcheries. Ultimately, the gas bubble disease at Fillmore resulted in a loss of about 50 percent of inventory. While emergency measures taken by Fillmore staff and

CDFW fish pathologists resulted in better conditions and lower gas super-saturation, the hatchery must be depopulated so that the issue can be addressed entirely. As soon as all trout are removed, hatchery staff and scientists will increase the gas diffusion capability of aeration towers at Fillmore, in order to handle supersaturated well water for the short and long term.

The status of these two hatcheries presented a substantial problem for trout stocking in Southern California that was solved in part by hatcheries in Central and Northern California. These hatcheries have sufficient catchable size trout to supply Southern California’s approved waters immediately and in coming weeks. Thanks to strategic planning and trout production at a statewide level, Northern and Central California can supply fish to Southern California without impacting originally scheduled trout releases in their respective areas.

Trout stocking for Southern California waters will begin this week and hatchery trucks are on the move. Hatchery staff will work quickly to distribute trout to as many approved waters as possible. Trout stocking to Southern California will initially be lighter than usual, but will likely pick back up in 2018. As Mojave River Hatchery comes back online, fish transferred to that facility will be fed and reared to maximize daily growth. We anticipate another large batch of catchable trout available for Southern California toward early spring 2018.

Hatchery staff will be doing everything possible, statewide, to maximize trout production and releases to approved waters in the coming months. Staff work diligently for the angling public and appreciate their continued support.

The statewide planting schedule is updated in real time online.

CDFW photos. Top: Steelhead trout at Mokelumne River Hatchery



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