 |
 |
California Academy of Sciences
Home What is a Settling Plate? Settling Plate Organisms Participating Schools Get Involved!
Eubranchus misakiensis Baba, 1960
This is an invasive species of nudibranch, or sea slug, from Japanese seas. It has been recorded from San Francisco Bay since the 1970's, and has spread throughout almost the entire Bay, feeding on colonies of the introduced hydroid, Obelia.
This photo of two Eubranchus nudibranchs shows the reproductive structures characteristic of simultaneously hermaphroditic opisthobranchs. The structures shown are only seasonally conspicuous; these specimens from Pete's Harbor in San Mateo County where taken on the the 29th of March 2002. Individuals are monoecious;each individual has both male and female reproductive organs and capabilities; and reproduction is the result of reciprocal copulation. There are natural barriers to self-fertilization, so it still takes two individuals to reproduce successfully. Visible in the image above are the ovotestes (o), the penes (p) and egg ribbons (e.r.) of E. misakiensis.