The rough-mantled nudibranch (Onchidoris bilamellata) is a mollusc thus it is related to periwinkles, scallops, and mussels. However, it is a shell-less mollusc, called a sea slug.
Nudibranch information:
- Commonly found in the intertidal zone.
- Feeds on barnacles.
- Have a pair of tentacles (rhinophores) at the front which are used for scent detection. These are retractile.
- Surrounding the anus at the rear are gills used for respiration, which collapse when out of water.
- Oval in shape with a maximum length of about 2.5cm (1 inch).
- They are hermaphrodites but need another to spawn. Will form dense aggregations when spawning.
- Produce a ribbon-like white egg mass that contains many thousands of eggs.
For information on other animals in our area, check out the Intertidal Zone Field Guide and the Introduction to Classification on the following website, www.huntsmanmarine.ca/html/resources1.html.
Toward the top of the rock are the nudibranchs and a white egg mass.
Nudibranch on the middle of the rock.
