A sea star deaths domino effect has started on the marine ecology in British Columbia's Howe Sound, say student researchers, and it's a warning sign for other species in the ocean.
Researchers at Simon Fraser University told the Canadian Press
they found sea stars dying by the millions in the summer of 2013 from Mexico to Alaska. While they said they don't know the exact cause, they attributed some of the deaths to a virus and others to unstable water temperatures.
"It's difficult to prevent further disturbances like this when you don't fully understand what the cause was," said Jessica Schultz, the Howe Sound research program manager and a master's student at the university.
Schultz and colleagues Ryan Cloutier and Isabelle Côté found in Howe Sound that the deaths of the sunflower sea star created a domino effect on the sound's marine ecology, said a university news release
"Howe Sound lost nearly 90 percent of its sunflower stars in a matter of weeks," Schultz said.
After the deaths, researchers discovered that the sunflower star's top prey, green sea urchins, quadrupled while the population of the sea urchins' favorite meal, the sea colander kelp, dropped by 80 percent.
The sea colander kelp is a critical rearing habitat for juvenile spot prawns, which have become a favorite delicacy for British Columbia chefs, noted the Vancouver Sun
"Spot prawns use sea colander kelp as a nursery when they settle out of the plankton," Schultz told the Sun. "With so many urchins and so much less kelp, we are really watching to see how that will impact the spot prawn population."
Côté said the sea star deaths have set off an "ecological domino effect" that has could mean changes in the food chain.
"It's a stark reminder that everything is connected to everything else," Côté said. "In this case, the knock-on consequences were predictable, but sometimes they are not."
Researchers said that until the sunflower stars reach their previous abundance, there's not another predator to keep the sea urchins in check.
"The sunflower star is one of the biggest sea stars in the world and it eats pretty much anything it can get its tentacles on, so when a predator is suddenly gone, it affects everything else around it," Schultz told the Sun.
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