Less Common Sea Stars (Phylum: Echinodermata)

Description: Due to sea star wasting syndrome among other environmental factors, there are several species of sea star that are no longer commonly seen as Haystack Rock. Bat stars (Patiria miniata) and sunflower stars (Pycnopodia helianthoides) could be found in the intertidal zone at Haystack Rock prior to the introduction of wasting in 2013, but are very rarely found today. There is hope that as the sea star population recovers, these species will return.

Bat stars can come in a variety of colors from gray, blue, green, purple or red, but all color variations have 5 arms that look like they are webbed. They can get up to 20 cm across.

Sunflower stars are easy to distinguish from other species because of their large number of arms - up to 24! They can be purple, orange, yellow, red, or anywhere in between. Sunflower stars are the largest sea stars in the world and can grow up to 1 m across. Unfortunately this species was one of the most heavily effected by wasting.

A decline in these stars has an impact on their ecosystems. As apex predators, sea stars help keep prey species like urchins and mussels in control. A decrease in sea stars has caused an over population of other species in some areas on the West Coast.

Habitat: Bat stars and sunflower stars can all be found in intertidal and subtidal zones. Bat stars range from southeast Alaska to Baja California, Mexico and prefer areas with lots of kelp. Sunflower stars range from Aleutian Islands, Alaska to Baja California, Mexico in a variety of substrate types.

Diet: Bat stars eat urchins, among other invertebrates, and decaying organic material. Sunflower stars have a reputation for being voracious predators and will eat a variety of foods including urchins, other sea stars, dead animals, and occasionally even seabirds.

Tide Pool Tidbits:

• Bat stars can have up to 20 symbiotic worms living on their underside at one time.

• The lifespan of bat stars is thought to be 30 years.

• Sunflower stars are the fastest moving stars in the world! They can travel more than 1 m per min, which is more than 6 times faster than a leather star (the 2nd fastest star).

• An average sized sunflower star can have 15,000 tube feet!

• While not yet official, NOAA is proposing to list sunflower stars as Threatened under the Endangered Species Act.

• All sea stars pump water through their body via a water vascular (hydraulic) system that allows them to move their tube feet and walk.

Reference:

Sunflower stars: NOAA, Monterey Bay Aquarium, The New Beachcomber’s Guide to the Pacific Northwest by J Duane Sept

Bat stars: Monterey Bay Aquarium, The New Beachcomber’s Guide to the Pacific Northwest by J Duane Sept