[2] The gulf sun star is native to the eastern Pacific Ocean and its range extends from Cape Mendocino in California to Nicaragua.

[4] Previous to that it was very common on rocks and under boulders in the lower and middle intertidal zone, with a density of up to one individual per square metre.

The population decline was associated with higher than normal water temperatures and the changes brought about by an El Niño event.

[4] Because this sea star is a top-level predator, its virtual disappearance was expected to have profound effects on the ecosystem.

[4][5] However, the predatory rock snail Morula ferruginosa increased in abundance and kept the barnacles on which the sea star had previously fed under control, and the ecosystem in balance.