Partnering in the effort to understand “melting” sea stars

Sea star wasting disease

In late 2013, some sunflower sea stars in British Columbia, Washington and California—and even along the Seattle waterfront—began dying from a condition that gives the impression of “melting.” The Seattle Aquarium joined the effort to understand the condition and its cause.

“Low-grade disease in sea stars is not uncommon,” noted staff veterinarian Lesanna Lahner at the time. “It’s previously been documented on a waxing/waning, potentially seasonal, occurrence in both captive and free-ranging sea star populations along the West and East coasts. In the past, these events have been mild. However, starting in October of 2013, a higher prevalence of disease in the wild population of several sea star species was documented near Vancouver, B.C., the Seattle waterfront, and other regions along the West Coast of North America.”

As part of a multi-institutional collaborative effort to quickly respond to this unusual mortality event in sea stars, Seattle Aquarium divers collected healthy and diseased stars from the waters surrounding the Seattle Aquarium in late October. Aquarium divers also continued to monitor levels of disease along the waterfront.

The animals collected were sampled according to a protocol carefully developed by several institutions, and samples were sent to our collaborators in New York at Cornell University and the Wildlife Conservation Society. The U.S. Geological Survey National Wildlife Health Center also became involved and helped to coordinate efforts and investigate other potential causes of disease, including toxins and fungal infections.

The condition has been labeled Sea Star Wasting Disease (SSWD) and no definitive cause has yet been identified. Research by the Seattle Aquarium, in conjunction with numerous collaborators, continues.