Bubbles and bladders

Winter is almost over, and the occasional blade of eelgrass is turning up on the beaches again. I found a few plants with roots and brought them home. The hermit crabs are happy about that; they love to sit up high on a green blade and watch the world go by.

View of the tank with winter seaweeds; red algae and brown wireweed. And 3 eelgrass plants.

The tall, brown seaweed bearing little round float bladders is a Sargassum, possibly Sargassum muticum, an invasive from Japan. For most of the winter, the hermits and snails ignored it, not interested in searching it for food. In the last few weeks, perhaps tired of having nothing to climb, a few have been found swinging on the upper branches, but now that there's a bit of eelgrass, they've abandoned the Sargassum again.

Few organisms have been found living on Sargassum muticum in British Columbia, though a number have been reported in Washington, Oregon and California. A study in southern California estimated that a 5 m tall plant hosts an average of 3,000 animals, including foraminifers, hydroids, flatworms, polychaete worms, leeches, snails, ostracods, cumaceans, isopods, gammarid and caprellid amphipods, opossum shrimp, euphausid shrimp, crabs and bryozoans ... (Nicholson et al. 1981) (The Exotics Guide)

Why BC critters are pickier than the ones in the U.S, I have no idea.

"Bubbles", hanging out on the eelgrass.