UC Santa Cruz PhD student Monica Moritsch stands knee deep in the chilly water at Terrace Point in northern Santa Cruz. This is a spot where marine biologists have been counting sea stars closely for more than 15 years.
“Just look high and low. Look in the cracks,” she directs her two interns in the search. “The small ones tend to hide in the crevices.”
In the tide pools carpeted with iridescent black-and-blue mussels, they quickly find what they’re looking for. “Oh, there’s two right here,” she says.
“Oh, there’s three!” says intern Samantha Chavez.
For two years, a mysterious disease has been melting sea stars along the West Coast into a gooey mess. Scientists suspect a virus caused the epidemic, which they call one of the largest marine disease outbreaks ever recorded. But after millions of sea stars died, they are now seeing sea star baby booms in some areas, offering a sense of hope for a comeback.
The purple and orange baby sea stars Moritsch found are about the size of a quarter. She says their size dates them to being born during the mass die off from the wasting disease.
“We’ve seen more babies in the last 12-ish months than we have had in the previous 14 years combined,” says Pete Raimondi, a professor of ecology and evolutionary biology at UCSC. His office overlooks Terrace Point, and Moritsch is a student in his lab.
“Now, that’s not characteristic of all sites, but it is an indication that there is substantial recruitment occurring,” he continues.
Recruitment simply means new babies, and the numbers have dumbfounded researchers like Raimondi. So amid the gruesome wasting disease, why are there more babies? To start, scientists think environmental stressors, such as warmer waters and pollution from nearby cities, might have made the sea stars more susceptible to disease.
And when animals become stressed, they tend to spawn.
After struggling starfish got hit with the disease, they reproduced eggs and sperm like crazy, shooting millions of them into the water to fertilize.
“We’re thinking this might be a very good sign for recovery, if they live,” Raimondi says. “We’re going to follow this new cohort of babies and see what their survivorship is over the year.”
Now he’s trying to figure out if the disease is still present and if these new babies can get it. His effort starts by mapping out where the babies are now.
So he and other researchers launched a website this month where citizen scientist beachcombers can submit information and photos of the baby sea stars they find.
“This is going to help us understand both the likelihood that there’s going to be a recovery and what the geography of the recovery will be,” he says.
Where the baby sea stars are matters because that will help scientists understand where a recovery might happen.
A thriving sea star population is important for the whole ecosystem.
Back out in the tide pools at Terrace Point where Moritsch and her interns are counting sea stars, they’re also counting baby mussels.