Species spotlight: Cushion sea stars
Updated: Dec 19, 2020
Species spotlight: Cushion sea star
If you have visited Bocas del Toro, you have likely seen one of most tranquil yet charismatic organisms - the cushion sea star. Cushion sea stars (Oreaster reticulatus) are a type of invertebrate belonging to the phylum Echinodermata. Their relatives include made other species of sea stars (did you know there are over 2,00 species of sea stars around the world?!) as well as brittle stars, sea cucumbers, sea urchins, and sand dollars.
Juvenile cushion sea stars tend to live in the seagrass where they can hide from predators. As juveniles they are also typically green in color, although I have also seen some beautiful red and literal “camouflage” patterns as well. As they mature, they change to a yellow or orange color and live in sandy areas, which are easier to move around than the seagrass beds.
Cushion sea stars primarily feed on small algae that cover the sand, but they also feed on the same microalgae that grow on blades of seagrass, and sometimes can be found feeding on sponges. They use their tube feet to pull the sand and algae towards the center of their body, where their mouth is located. Sea stars actually have two stomachs - a pyloric stomach that stays inside, and cardiac stomach that the sea star can extrude and allows for external digestion of food!
If you see cushion sea stars in the wild, please enjoy their beauty without touching them. Because of the way they feed, if they are touched or picked up, they retract their cardiac stomach and stop feeding. Over time, repeated touching may cause stress and affect their nutrition. In addition, chemicals on our hands, such as sunscreen, may be harmful to them.
This is especially true at Playa Estrella, a beautiful beach in Bocas del Toro known for a high abundance of sea stars in the shallow beach but also a high number of tourists. If you visit Playa Estrella, please take photos next to the sea stars without touching them, and politely educate other visitors to the beach. The student researchers at the School for Field Studies also created a wonderful 2-minute video about sea stars and how to be a responsible tourist at Playa Estrella that you can find here.
Below is a series of educational infographics created about sea stars and Playa Estrella - please download and share!