HRAP Online Encyclopedia

Nudibranchs

Nudibranchs, more commonly known as sea slugs, are beautiful tide pool invertebrates that come in a wide range of sizes (from 0.25 to 12 inches) and colors. The two main subgroups of nudibranchs found at Haystack Rock are dorids and aeolids (pronounced ee-oh-lids). Dorids have smoother-looking backs and a little fluffy-looking patch of gills near their back end. On the other hand, aeolids have organs called cerata sticking out from all over their backs, which they use to breathe. Other nudibranchs sometimes found at Haystack Rock that don’t belong to the dorid or aeolid subgroups include the frosted nudibranch (in the dirona subgroup), the sea clown nudibranch (in the triopha subgroup), and various nudibranchs in the dendronotid subgroup. With some patience nudibranchs can be found year round, but they are most plentiful in the spring. Each species of sea slug will stay close to their food source, but in general the best places to look for nudibranchs are in the tide pools near The Needles.

Aeolids

Dorids

Others