A scuba diver’s delight, the sunflower sea starfish, a key species of ocean has been listed as Critically Endangered by the International Union for Conservation of Nature (IUCN), which maintains a “Red List of Threatened Species”.

Citing a 90 per cent decline in the species’ global population, the IUCN on December 10 officially placed the sunflower sea star (Pycnopodia helianthoides) on the group’s Red List of Threatened Species, meaning that it is critically endangered. The next step is extinction.

A partnership of more than 60 institutions had made the official request to the IUCN to put it under the Crticically Endangered list..

“The sunflower star was the most susceptible of the 20 sea star species affected by a multi-host pathogen and has rapidly gone from being the most common subtidal sea star on the U.S. West Coast to critically endangered,” said Drew Harvell, professor of ecology and evolutionary biology in the College of Agriculture and Life Sciences, who helped to place the animal on the Red List. “This highlights the impacts disease can have on the stability of our nearshore ecosystems.”

Among the largest of the sea stars, the sunflower sea star is close in size to a city street sewer cover, with a voracious appetite to match. It scoots along the ocean floor like a robotic vacuum cleaner, gorging on everything in its path.

Populations of many sea star species dropped precipitously starting in 2013, with the sunflower star the hardest hit, due to warming oceans and sea star wasting syndrome, Harvell said, according to reports.

Scientists from The Nature Conservancy and Oregon State University, who led the listing effort, estimate that 90.6 per cent of the sunflower sea star population is now lost from the outbreak, with as many as 5.75 billion dead from the disease.

The Nature Conservancy and University of Washington are partnering to establish a captive breeding program with the option for re-introducing individuals to the wild, said the reports.

This many-legged star of the sea could be seen in coastal waters in Northern America. But during El Niño and the Warm Blob, a microorganism that triggers sea star wasting disease took root, and several types of sea stars died as ocean temperatures rose along the western coast from 2014-2016.

The sunflower star was badly damaged - this aquatic behemoth is now scarce, although some organisms have since recovered. Scientists predict that a whopping more than 5 billion sunflower stars declined from this epidemic, representing over 90 percent of their total population worldwide.