Center for Biological Diversity

For Immediate Release, January 18, 2021


J.P. Rose, (408) 497-7675,

Lawsuit Challenges Trump Administration’s Failure to Protect Rare L.A. Fish Known for Elaborate Mating Rituals

LOS ANGELES— The Center for Biological Diversity sued the Trump administration today for failing to protect Southern California’s unarmored threespine stickleback, a tiny scaleless fish known for its elaborate mating rituals.

These critically endangered fish used to inhabit the Los Angeles River and other nearby streams, but they now survive only in the upper Santa Clara River watershed near the Angeles National Forest and a single creek in Santa Barbara County.

Yet the Trump administration has failed to prepare an updated recovery plan or take other urgent steps to preserve the species.

“These little fish have survived for millennia in Los Angeles-area streams, but the Trump administration’s inaction has helped push these living icons of California to the brink,” said J.P. Rose, a Center attorney. “Habitat destruction and water pollution are wiping them out. Without immediate and ambitious new safeguards, these fish will be relegated to history books and museums.”

Even though the species was protected under the Endangered Species Act more than 50 years ago, stickleback populations are increasingly threatened by habitat destruction, water pollution, groundwater withdrawals, wildfire and non-native predators.

Male sticklebacks are the nest builders and engage in elaborate zigzag dancing motions to woo females. But once a female accepts a male’s overtures and deposits her eggs in the nest, the male unceremoniously ejects the female.

“Katy Perry’s ‘Hot N Cold’ may be about an up-and-down human relationship, but it also echoes the strange world of stickleback romance. 'You're yes then you're no, You're in then you're out,’” said Rose. “These distinctive little creatures are an important part of Southern California’s biodiversity, and we’ve got to protect them.”

A recovery plan was created in 1985 for the stickleback, but it did not satisfy the requirements of the Endangered Species Act. Although the U.S. Fish and Wildlife Service acknowledged in 2009 that the 1985 plan does not reflect the best available science, it has not prepared an updated plan. The recovery plan also does not address how climate change may impact the stickleback.

The Service concluded in 2009 that none of the recovery criteria in the 1985 plan have been met. Although the Service is required to prepare an updated status review every five years, it has not prepared one since 2009.

Since 1985 a single new population of stickleback has been discovered in Bouquet Creek but two known populations have been wiped out. The fish once existed throughout the Los Angeles basin, there are now only five known remaining populations.

A 2015 study found the fish at “high risk of extinction,” and surveys did not identify stickleback in areas where they were abundant in previous years.


The male threespine stickleback establishes a territory that he vigorously protects, builds a nest in the sand, and, after cementing the nest materials together with mucus threads spun from his kidneys, burrows through the nest to make an exit and entrance.

When the nest is ready, he searches for a female carrying eggs and swims near her in a zigzag, dancing motion. If the female is attracted, she follows him to his nest, where she deposits her eggs. The male immediately fertilizes the eggs and drives the female away. Over the course of the breeding season, he may entice other females into his nest as well. Males protect both eggs and fry from predators. Incubation time averages six to eight days.

The species was historically present in the Los Angeles, Santa Ana and San Gabriel Rivers, but by 1985 the fish were limited mostly to a small portion of the upper Santa Clara River drainage in northwestern Los Angeles County and a small area in the San Antonio Creek drainage in Santa Barbara County.

More than 35 years ago the Los Angeles Times wrote that “[e]ven in its native Los Angeles, the two-inch fish is the endangered creature nobody knows.”

The Center for Biological Diversity is a national, nonprofit conservation organization with more than 1.7 million members and online activists dedicated to the protection of endangered species and wild places.

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