The wasting disease was observed in January in the ocean near Nanaimo by Ed Singer, the owner of Sundown Diving.
"It looked like the centres of them were melting," he told CBC News. "It looked like the outside perimeter was still live, and like the middle part was dying."- Watch Ed Singer's videotape
Jeff Marliave, the vice president of marine science with the Vancouver Aquarium, says scientists still don't know what's causing the die-off, which has been observed along the Pacific Coast of the United States as well.
Scientists have dubbed it sea star wasting syndrome, and they speculate that there could be a pathogen, or a number of factors at play.
But Marliave says so far, his team is not worried the syndrome could eradicate the species.
"No, not at all," Marliave told CBC News on Wednesday morning. "With starfish generally, there are various pathogens that will control an overabundance and sunflower stars were really seriously over abundant for a period over a decade"
"Disease is one of the long term accepted methods that nature takes to control populations," says Marliave, "So we may be coming to realize that pathogens are the leveller with echinoderms, sea urchins and starfish, that tend towards huge population explosions"
He also added that while the adults are wasting away, they were actively reproducing all summer and so far, the baby sunflower stars don't seem to be affected.
But he still does have some concerns, citing the dumping of ballast water from ships in local waters, and the mixing and matching of invasive organisms as a result.