Scientists Help Save a 24-Armed Sea CreatureZoomen Sie dieses Bild to toggle caption Dennis Wise/University of Washington Dennis Wise/University of WashingtonJason Hodin pulls up a rope hanging from a dock off San Juan Island, Washington. The end of the rope has a square Tupperware container the size of a sandwich. There are mesh-covered holes on the sides that allow water to flow through. Hodin lifts the lid to look inside and sees some shell fragments. Hodin points out some reddish-orange spots."See that? "See that little dot right there in my finger?" Hodin. Hodin says, "That's a juvenile star from the sea that's only a month old."It is only about the same size as a poppy seed. When this baby is fully grown, it can be as large as a manhole cover. This is Pycnopodia Helianthoides, also known as the sunflower sea star. It is one of the largest sea stars in the world with an arm span exceeding three feet. This star was once common in the waters off the West Coast.It is now in grave danger and is being driven to extinction by a mysterious and deadly disease.Hodin and his Friday Harbor Laboratories colleagues from the University of Washington have spent two years trying to figure out how to raise the species in captivity. This is a desperate act in the hope that lab-grown sunflower sea star can be reintroduced to areas where it has been lost.Zoomen Sie dieses Bild to toggle caption Dennis Wise/University of Washington Dennis Wise/University of WashingtonThe voracious predator used the seas to patrol nearly 2,000 miles of water, stretching from Alaska to Baja California. Brightly colored bodies, which come in vibrant shades of orange, pink and blue, would move on the seafloor with as many as 24 arms. They would eat mussels, scallops, and sea urchins. They were particularly responsible for protecting vital forests of kelp that are home to many marine species by consuming sea urchins.However, the population of sunflower sea stars has declined by 80-100 percent in recent years. Hodin says that the California sunflower sea stars have declined by more than 95%. Some people believe they are extinct in the wild. There have been scattered reports that people may see a few.This species is particularly vulnerable to a wasting illness that has affected more than 20 sea star species in the past three years. Hodin said that sick sea stars are a horrible sight to see. He says he witnessed the scene and it was not pleasant. They kind of dissolve into a heap of goo."Hodin said that the Nature Conservancy approached Hodin in 2019 to discuss the possibility of establishing a program to produce sunflower sea stars. Because sea stars can transform from being bilaterally symmetrical larvae into juveniles with five-sidedsymmetry, he was already interested in the science behind them. He was willing to raise large numbers of sunflower stars until they reached adulthood, even though nobody had done anything like it before.Zoomen Sie dieses Bild to toggle caption Dennis Wise/University of Washington Dennis Wise/University of WashingtonHodin says that there have been very few publications on raising this species, even at the larval or embryo stages.He couldn't answer some of the most fundamental questions like, What did this species eat in its early years? How fast could it grow?Hodin explains that nobody knows how to age sea stars so if you see one in the wild, you don't know how old it actually is. It could be as old as two years. It could be 50. It could even be 100."His team began by removing sunflower sea stars from the wild. These giants are now living outside the lab in large burbling tanks.Hodin says, "I didn’t really expect how exuberant they would be." "You get to get to know them and get to know each of them individually. It was obvious from the beginning that they could be distinguished by their colors. We gave them names."Many of their names are tied to their colors. Prince has purple tips on his arms, for instance.Zoomen Sie dieses Bild to toggle caption Dennis Wise/University of Washington Dennis Wise/University of WashingtonFleur Anteau, a researcher, says that this is 'Deep Blue'. She's our largest. "Some of the birds, when I open their cages, will actually start moving their arms towards the surface, much like Olga. Some of them can be a bit shier.Once they grab a mussel, even the most timid of people can suddenly become more confident. They lean over their prey to swallow it whole. Anteau notes that predators are only visible when food is available.She points to the red spot at each end of each arm and says, "They are looking at you." Although they don't have the same eyes as us, they can see light and dark.This lab discovered how to obtain sperm from wild-caught adult fish and produce their offspring. They are approximately three inches in size and are the oldest sea stars they have produced.Only a handful of young sea stars have made it to this stage in the lab. Given how little they knew at the beginning and the fact that they had the challenge of working out their techniques in a world pandemic,Hodin feels fortunate to have been able to get so many.Hodin says, "We think they may be reproducible by next year. Based on the ones we've seen in field." It's great news that they grow fairly quickly.Zoomen Sie dieses Bild to toggle caption Dennis Wise/University of Washington Dennis Wise/University of WashingtonThe research team has learned all the techniques needed to raise these sea stars and now they want to make as many young stars as possible. The lab is filled with glass pickle jars containing larvae and food containers that can hold the poppy seed-sized juveniles.Hodin suggests that the first lab-grown sea stars be released into local waters to see how they do in the wild. If all goes well, it may be possible to restore California's population in the future.However, sea star wasting could still be a danger.Drew Harvell is a Cornell University professor emeritus and a Friday Harbor Labs researcher.She says scientists are still not agreeing on the cause of the killing. Some blame an infectious agent like a virus while others point out warming oceans and other environmental changes.Harvell, the author of Ocean Outbreak: Confronting The Rising Tide Of Marine Diseases, says that it is controversial. She believes that there is a lot evidence to support the idea that sea star wasting disease can be infectious.She and her colleagues will be starting new lab experiments this month to verify that idea. Extracts from sick sea stars can be injected into healthy fish in a fish pathogen laboratory. Because they are so vulnerable, she will be using sunflower sea star extracts.Harvell says that these are hard experiments to consistently run, and that if you do them with a species which is somewhat resistant, sometimes nothing happens."She says that even if scientists are not able to determine the cause of this disease, it might still be worthwhile to try reintroductions of captive-bred sea stars into the wild.Harvell says, "At some point, we would just have to likely go forward," even though it wouldn't be scientifically sound.Zoomen Sie dieses Bild to toggle caption Dennis Wise/University of Washington Dennis Wise/University of WashingtonHodin wishes that he had known whether the sea stars he is raising are susceptible. Hodin is always on the lookout to see if his beloved animals become ill.To tenderly feed the tiny mussels to one of the young sea stars, he uses a pair tweezers. It wraps its arm around the treat.Hodin says that "their adult-like behaviors are beginning to emerge at these smaller sizes, and that has been really fascinating to observe." He also says that he feels a strong attachment to all the animals he's fostered. "I see myself as their foster mother. They are my foster parents. I care for them, try to maximize their growth, and watch them grow.He even says that he dreams about them. He had dreamt the night before of being surrounded with water in a house-sized tank.
