Sunflower Star Decline
The once abundant sunflower sea star (Pycnopodia helianthoides) suffered a catastrophic population decline on the West Coast due to the sea star wasting disease.
This outbreak was caused by a strain of Vibrio pectenicida bacteria alongside the 2014-2016 Pacific marine heatwave. This decline led to the functional extinction of sunflower stars from Northern Mexico to Southern Oregon.
As apex predators of bottom-dwelling invertebrates like sea urchins, sunflower sea stars help keep kelp forests in balance. Their loss sent rippling effects across ecosystems as sea urchin populations boomed and decimated kelp forests.
Sunflower stars occur down to 1,300 feet and across nearly 7,500 miles of coastline, making monitoring logistically challenging. Thus new tools, like environmental DNA (eDNA), are needed to provide sensitive, effective, and low-cost ways to survey sunflower sea stars.
The once abundant sunflower sea star (Pycnopodia helianthoides) suffered a catastrophic population decline on the West Coast due to the sea star wasting disease.
This outbreak was caused by a strain of Vibrio pectenicida bacteria alongside the 2014-2016 Pacific marine heatwave. This decline led to the functional extinction of sunflower stars from Northern Mexico to Southern Oregon.
As apex predators of bottom-dwelling invertebrates like sea urchins, sunflower sea stars help keep kelp forests in balance. Their loss sent rippling effects across ecosystems as sea urchin populations boomed and decimated kelp forests.
Sunflower stars occur down to 1,300 feet and across nearly 7,500 miles of coastline, making monitoring logistically challenging. Thus new tools, like environmental DNA (eDNA), are needed to provide sensitive, effective, and low-cost ways to survey sunflower sea stars.
eDNA Tools for Conservation
In 2025, scientists from the NOAA Pacific Marine Environmental Laboratory’s Ocean Molecular Ecology program developed a first-of-its-kind eDNA assay to identify sunflower sea stars. This tool detects the molecular footprint of sunflower stars from the DNA they shed in seawater. This work would not have been possible without help from the Sunflower Star Laboratory, Association of Zoos and Aquarium’s Saving Animals from Extinction program, University of California Los Angeles, University of California Merced, and California Polytechnic State University, San Luis Obispo.
The assay proved to be highly sensitive and accurate through testing in laboratories, in aquaria, and in the ocean paired with dive
surveys. These paired surveys found strong correlations between eDNA concentrations and estimated abundance. This new eDNA tool will aid resource managers working to reintroduce sunflower stars across their native range, monitor population trends, and search for places where sunflower stars may be recovering from sea star wasting disease.
In 2025, scientists from the NOAA Pacific Marine Environmental Laboratory’s Ocean Molecular Ecology program developed a first-of-its-kind eDNA assay to identify sunflower sea stars. This tool detects the molecular footprint of sunflower stars from the DNA they shed in seawater. This work would not have been possible without help from the Sunflower Star Laboratory, Association of Zoos and Aquarium’s Saving Animals from Extinction program, University of California Los Angeles, University of California Merced, and California Polytechnic State University, San Luis Obispo.
The assay proved to be highly sensitive and accurate through testing in laboratories, in aquaria, and in the ocean paired with dive
surveys. These paired surveys found strong correlations between eDNA concentrations and estimated abundance. This new eDNA tool will aid resource managers working to reintroduce sunflower stars across their native range, monitor population trends, and search for places where sunflower stars may be recovering from sea star wasting disease.
Reintroducing Sunflower Sea Stars
In response to the seastar wasting disease outbreak, conservation groups brought surviving sunflower stars into captivity. This critical intervention enabled two important discoveries: how to successfully spawn sunflower stars in captivity (closing the life cycle), and the identification of Vibrio pectenicida as the primary driver of sea star wasting disease. Now, scientists are beginning to reintroduce captive-bred sunflower stars into the environment. The eDNA tool we designed is being used to monitor reintroduction efforts.
In response to the seastar wasting disease outbreak, conservation groups brought surviving sunflower stars into captivity. This critical intervention enabled two important discoveries: how to successfully spawn sunflower stars in captivity (closing the life cycle), and the identification of Vibrio pectenicida as the primary driver of sea star wasting disease. Now, scientists are beginning to reintroduce captive-bred sunflower stars into the environment. The eDNA tool we designed is being used to monitor reintroduction efforts.
eDNA Detects California Sunflower Stars
In recent years, sightings in Northern California tidepools and Olympic Coast National Marine Sanctuary have sparked hope that sunflower stars may be recovering in parts of their native range.
In 2025, a diverse group of scientists from NOAA, nongovernmental organizations, and academia undertook a rapid assess-
ment of 39 sites across California to understand the current extent of their southern range. These sites included known historical hot spots where sunflower stars had become functionally extinct, areas of recent confirmed and anecdotal sightings, and sites within and immediately outside Marine Protected Areas. Using our novel eDNA tool, scientists found evidence of sunflower stars at six sites in California in Mendocino, Sonoma, and San Mateo counties. Two of these sites have since been visually confirmed with diver surveys. The detection at Half Moon Bay marks the first detection of sunflower stars south of San Francisco in a decade!
These results reinforce the impact of eDNA for studying rare and elusive species over large ranges and with limited resources.
We are now transitioning this eDNA tool for public use. For example, research in Olympic National Marine Sanctuary with the NOAA Northwest Fisheries Science Center is pairing eDNA detection with visual surveys to further operationalize eDNA methods for management efforts.
In recent years, sightings in Northern California tidepools and Olympic Coast National Marine Sanctuary have sparked hope that sunflower stars may be recovering in parts of their native range.
In 2025, a diverse group of scientists from NOAA, nongovernmental organizations, and academia undertook a rapid assess-
ment of 39 sites across California to understand the current extent of their southern range. These sites included known historical hot spots where sunflower stars had become functionally extinct, areas of recent confirmed and anecdotal sightings, and sites within and immediately outside Marine Protected Areas. Using our novel eDNA tool, scientists found evidence of sunflower stars at six sites in California in Mendocino, Sonoma, and San Mateo counties. Two of these sites have since been visually confirmed with diver surveys. The detection at Half Moon Bay marks the first detection of sunflower stars south of San Francisco in a decade!
These results reinforce the impact of eDNA for studying rare and elusive species over large ranges and with limited resources.
We are now transitioning this eDNA tool for public use. For example, research in Olympic National Marine Sanctuary with the NOAA Northwest Fisheries Science Center is pairing eDNA detection with visual surveys to further operationalize eDNA methods for management efforts.