While doing some San Francisco Area tidepooling, we came across a few examples of this colorful creature. This pink nudibranch brightens local tide pools. Nudibranchs, also called sea slugs, are sea snails without a shell.
This stunning creature is named for its vibrant, rosy-pink coloration, which it gets from its diet of pink encrusting bryozoans, just like flamingos get their flamboyant pink hue from the shrimp they eat. The Hopkin’s Rose Nudibranch is found in the intertidal zone, where it can be seen on rocks, pilings, and other hard surfaces.
It is most common in the warmer waters of Southern California, but its range extends from Northern Baja California, Mexico, to the lower Oregon coast. Historically, it was rare to see Hopkin’s rose nudibranchs north of San Francisco, but in recent years they have become more common in southern Oregon.
Many nudibranchs wear bright colors that may warn predators that they taste bitter or foul. Usually the only animals that eat nudibranchs are other nudibranchs. The name “nudibranch” means “naked gill,” and the feathery gills of these animals take many fancy forms.
The species grows to be about an inch long and is nearly weightless. Like other marine gastropods, this nudibranch has a flat, muscular “foot” along the ventral or bottom side of its body that it uses to crawl along the substrate.
