For the first time in California, lab-grown sunflower sea stars have been temporarily roaming the ocean floor in Monterey Bay.
The invertebrate species, once abundant, have become functionally extinct after a massive die-off event in 2013-2014 linked to a strain of the bacterium Vibrio pectenicida. Since then, the Sunflower Star Laboratory, a nonprofit in Moss Landing, has been working on breeding efforts over the years to deliver the stars to partners across the state. Eventually, the plan is to reintroduce the sunflower stars, keystone predators in kelp forest ecosystems, back into the wild.
Over the summer, the Sunflower Star Laboratory got one step closer to that goal, leading a collaborative research project which took 16 of these sea stars out to Tankers Reef in the Monterey Bay. During a number of sessions over the span of a couple months, a team of divers would monitor the invertebrates for two hours at a time, collecting data before bringing the sea stars back to the lab for analysis.
“We did these studies to answer the key questions that we need to answer before we transition to permanent outplanting in our state, which is going to happen in the next one to three years,” says Reuven Bank, executive director of the Sunflower Star Laboratory. “Across all experiments, what we saw was the strong restoration potential of sunflower stars to be able to transition urchin barrens back into healthy kelp forests.”
Researchers brought the sea stars out to look at their feeding habits—what they ate and how they grew—and how they might disperse on the ocean floor once released. One star traveled more than 50 meters in two hours, showcasing their potential for traveling once released.
Rather surprisingly, the sea stars ate more than 3.5 starved urchins per day (urchins with less meat and nutritional value to them), and grew over 50 percent in one month, findings that when coupled with previous research show that the stars don’t differentiate between healthy and starved urchins when feeding. “That would be like if we had a Zoom call a month later and I weighed [100 pounds] more and I had just been eating twigs the whole time,” Bank says.
The presence of the sea stars also suppressed urchin activity up to five meters away through what researchers call a “landscape of fear,” results that highlight how effective the stars could be at protecting kelp forests from being overwhelmed by urchins.
Overall survivorship was 88 percent; two of the 16 stars in the study died with one testing positive for Vibrio.
The next year brings potentially interesting conditions with El Niño, where researchers see warm-water events as an opportunity to collect more data. If a small-scale permanent study occurs during a heat wave, according to Bank, researchers can measure how the stars fare under those conditions, looking at things like survival and dispersal, which will help guide larger restoration efforts.
“Our research is focused on the restorative power of sunflower stars, where by reintroducing them, they can help transition urchin barrens back into kelp forests and defend healthy kelp forests,” Banks says, “and bring balance back to those ecosystems.”