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These voracious sea stars may soon restore California’s battered kelp forests · Best of: Features

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  These voracious sea stars may soon restore California's battered kelp forests. Written
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  by Amanda Hight, This article is being read by an automated voice
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  generated by Everlet. An audacious effort to restore a critically endangered
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  species to the California coast has moved one step closer to fruition,
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  after scientists temporarily released more than a dozen lab reared sunflower stars
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  into Monterey Bay. Once a common sight for divers, these manhole-sized, many
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  armed sea stars have not been seen south of the Bay Area
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  since 2018, after a mysterious illness killed as many as six billion
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  individuals along The west coast of North America. Set free the lab
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  reared animals quickly devoured their preferred prey, sea urchins, which have ballooned
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  out of control in the years since the outbreak. The star's successful
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  hunting raises hopes that the animals could one day be set free
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  for good, helping to restore urchin barons into lush, productive kelp forests.
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  This work is the foundation for the upcoming future permanent outplanting in
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  our state, said Reuvenbank, the executive director of the Sunflower Star Laboratory,
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  which oversaw the research. What we've found really supports the strong restoration
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  potential of Sunflower stars, and that future outplanting can have a significant
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  positive effect on the environment. Between twenty thirteen
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  and twenty seventeen, a fast moving, highly fatal disease known as Sea
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  Star Wasting Disease swept up the west coast, causing widespread death among
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  more than twenty species of sea star. Sunflower stars, known scientifically as
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  Pynopodia heliantoids, were hit particularly hard, declining by roughly ninety two percent
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  across their historical range, from Baja California, Mexico, to the Aleutian Islands
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  off of Alaska. Today the species is rarely found south of Puget
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  Sound. It took years for scientists to untangle the mystery underlying wasting
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  syndrome, and many questions remain to this day, but in twenty twenty
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  five researchers identified the bacterium Vibrio pectinicidus the likely cause dot. What
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  triggered the outbreak in twenty thirteen remains unknown, yet subsequent research has
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  shown that the bacterium tends to thrive in warmer waters, and there
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  were several notable heat events around that time. Including a massive, unprecedented
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  marine heat wave in the Pacific Ocean known as the Blob. Without
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  their natural predators, urchin populations have boomed in the years since the
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  outbreak swept through. As urchin numbers have grown, so have their appetites,
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  such that once lush kelp forests up and down the coast have
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  been devoured, turning them into urchin barrens devoid of other life. In
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  Northern California, as such as ninety five percent of kelp forests are
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  now in decline. Kelp forests provide a myriad of benefits both ecological
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  and economical, adding two hundred fifty million dollars each year to California's
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  economy, and so there's tremendous interest in restoring them. The Conservation Nonprofit
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  Sunflower Star Laboratory started in twenty twenty one with the goal of
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  not just regrowing sunflower star populations, but restoring all the benefits they
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  bring to the ecosystem. Today, the Star Lab partners with academic and
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  conservation groups such as the Reef Check Foundation, the Monterey Bay Aquarium,
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  Moss Slanding Marine Laboratories, the California Department of Fish and Wildlife, California
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  State University, Monterey Bay, Hopkins Marine Station, and the Monterey Bay Dive
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  Company Underwater Company in their work. Pretty much every group working on
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  marine issues in this part of the world has been involved in
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  one way or another, which we're very excited and proud of, Banks
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  said. None of it could have happened without many of the marine
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  institutions donating their time, their boats, their people to support this effort.
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  Hard at work. Last year the group transplanted stars into the waters
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  of Monterey Bay in a series of caged experiments to see whether
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  the captive bred individuals could hack it in the wild. All but
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  one survived their month at sea, and The one that didn't make
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  it likely died from cannibalism, Kim said. Critically, none of the stars
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  showed any evidence of disease. This summer, researchers carried out additional experiments
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  to re-establish how sunflower stars will fit into the broader kelp forest
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  ecosystem. Members of the collaboration outplanted sixteen palm sized sunflower stars in
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  enclosed cages onto an urchin barren in Monterey Bay. Half of the
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  animals were given an unlimited supply of starved urchins, mimicking They poor
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  condition of urchins found in barrens devoid of food, while the other
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  half were provided with unlimited, well fed urchins that might be found
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  in a healthy kelp forest. The stars voraciously consumed the urchins, regardless
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  of whether the urchins were starved or not. When the urchins were
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  of lower quality, the stars simply ate more of them to compensate,
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  gaining more that fifty percent of their body mass, on average, over
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  the course of the month. At the same time, divers also observed
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  them landscape around the cages to see if the presence of the
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  stars prompted any behavioral cages among other areas other residents. They found
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  that urchins fled the immediate vicinity of the cage, and that such
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  effects were detectable even dozens of feet away. The urchin's avoidance also
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  persisted for weeks after the stars were removed. We went from seeing
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  up to sixty urchins in a single square meter to drastically zero.
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  Andrew Kim, a co founder of the Sunflower Star Laboratory and its
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  laboratory manager, told S F Gate. It was very clear that they
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  didn't want to be anywhere near where these stars were. Lastly, the
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  team released a handful of stars into the reef, following them over
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  the course of two hours to observe their behavior. Divers chaperoning the
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  stars on their walkabouts noted that several of the animals immediately left
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  the cages to explore their surroundings, feeding on any urchins they came
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  across. This portion of the experiment marks the first time a sunflower
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  star has roamed freely in Monterey Bay since twenty eighteen, and the
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  first time lab reared stars have been released into California near shore
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  ecosystems. Collectively, The results show that sunflower stars are apex predators in
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  their environment, and that the have the ability to drastically alter the
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  landscape, potentially restoring kelp forests to areas that are today barren. Bank
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  told SF Gate the group is planning another one to three years
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  worth of work before fully reintroducing the species into the wild Wasting
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  syndrome remains a concern, and the caged feeding experiment conducted earlier this
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  summer was ended a month early after two o individuals began to
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  show symptoms consistent with the disease, including lethargy and the loss of
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  limbs. Notably, the area was once again experiencing abnormally high temperatures. The
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  animals were quickly removed from the ocean and brought back to the
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  lab, there subsequent tests by the California Department of Fish and Wildlife
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  confirmed the presence of Vibrio in one individual, as well as in
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  the ambient environment where the experiments were held. The confirmation marks the
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  first documented case of natural transmission of this pathogen in California waters,
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  although Kim notes that the test has not been widely vetted or
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  adopted by other researchers. Even still, having a seemingly accurate test for
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  this virus has been a game changer, Kim said, adding that the
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  team continues to monitor different species of sea stars in the wild
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  to identify where the virus may be lurking in isolated pockets. In
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  addition to the risk of stars falling will there's also the added
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  consideration that the majority of the individuals in captivity today stem from
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  a single cohort spawned on Valentine's Day in twenty twenty four at
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  the Birch Aquarium in La Jolla. We need to make sure that
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  the stars we're putting out there are not from a single cross
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  and that they're not full siblings, he said. Otherwise we end up
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  with a really genetically weak population. Here too, though, the group is
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  making progress. In January of this year, the mother of the Valentine's
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  Day cohort spawned again, and scientists were able to fertilize her eggs
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  with spur collected from three males, creating a new cohort dubbed the
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  Kelp Pop Urchin Hunters, after the widely popular film K Pop Demon
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  Hunters. And several months ago, eggs from a female at the Heel
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  the Bay Aquarium in Santa Monica were used to create four new
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  lineages, collectively named the Chicken Fingers Cohort, in reference to the female's
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  unique texture. Moving forward, members of the collaboration will continue raising the
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  young for future experiments and working together towards the ultimate goal of
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  reintroduction. The Star Lab already has a few sites in Central and
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  Northern California they're considering. First, they'll need to thoroughly characterize them so
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  that they can better assess the changes that happen when the stars
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  are reintroduced. We've got people preparing for that work, Bank told SF
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  Gate. It's definitely an all-hands-on-deck moment.