SAN FRANCISCO (KGO) — Keeping track of starfish along our coastline has been an urgent mission for Rebecca Johnson, Ph.D., of the California Academy of Sciences. She and her teams of volunteers watched as several species, including the giant star sunflower, were decimated by a debilitating disease possibly triggered by a marine heat wave about a decade ago, which set off a ripple effect in the ecosystem.
“The loss of this huge starfish allowed one of its prey items, the purple sea urchin, to explode its population. And so with an exploding population of these sea urchins, there was a decline in marine algae, because the Sea urchins are voracious predators, herbivores of marine algae,” Johnson said.
She says the explosion of hungry purple urchins has become a long-term threat to kelp forests, which provide important benefits by sequestering carbon and providing critical habitat for marine life. They have been particularly destructive to Bull kelp, which is prevalent along the northern California coast.
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“The kelp forests are amazing. I mean, they are nurseries and habitats for tons of different species of fish, for many, many different invertebrates, for otters on the southernmost coast. But they also protect the coast from storm surges. They, you know, dampen the waves,” adds Johnson.
While many species have recovered along the coast, Johnson says Sunflower Star is still largely missing. And with the pressures of climate change, there is constant concern about what the future might hold.
Enter Senior Biologist Riah Evin, with the Academy’s captive breeding program. As a father-to-be, he is currently keeping an eye on the little specks that will become adult “bat stars.” And while bats aren’t endangered, Evin says the secrets she’s uncovering could one day help other species like sunflower stars.
“Using what we’ve learned raising star bats, to help that species, those are critically endangered species. And just learning more about their background, what their life cycle is like, what their nutritional needs are, and that’s a great doorway to actually do some kind of launch program,” Evin said.
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She explains that plans to release any species would likely be far in the future. But there is growing interest around the world in learning about the biodiversity of star populations: research is geared in part to learning what genetic traits might allow a species to survive pressures like warming ocean waters or marine diseases. .
“So this was our catalyst to make sure we can do it here internally and use it as a starting point to work with other starfish species,” he says.
Academy researchers are doing similar work with coral, which is also facing pressure from climate change and fluctuations in the marine environment. They hope that work on both species will help scientists better understand changes along our coastline, and perhaps better manage the fragile ecosystems and predators like starfish that help keep it in balance.
Now there are calls from some experts to reintroduce populations of sea otters to the north coast, which also feed on sea urchins. The hope is that, like starfish, otters will help kelp forests by keeping hungry urchins at bay.
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