Hopkins Rose Nudibranch


Two Hopkins Rose Nudibranchs with a Spanish Shawl
Hopkins Rose on algae looking for bryozoans Hopkins Rose

Hopkins Rose (Okenia rosacea )

The Hopkins Rose Nudibranch is very easily identified as the whole animal is pink in color. This Nudibranch is usually about an inch long. The body is covered by drooping spines that resembles a shaggy dog. This nudibranchs feeds almost exclusively on another very small marine organism called Bryozoans. These are really small animals that form colonies similar to coral.
Two Hopkins Rose Nudibranchs with a Spanish Shawl

Spanish Shawl (Flabellina iodine)

This nudibranch is also easily identified as it has a bright blue/purple body with orange to yellow appendages ( cerata ). This animal is usually about 1-2 inches in length and found in pools of water closer to the ocean. This animal feeds exclusively on a single species of hydroid a very small marine animal. Spanish Shawls have an interesting defense mechanism. They will swim or flutter away if they are threatened. This swimming however is slow but can be effective against even slower moving predators like the predatory sea slug navinax.
Description - Nudibranchs are marine mollusks similar to the snails and slugs found on land. Nudibranchs are unique in that their gills are located on the outside of their bodies. Most all other slugs have their lungs on the inside of their bodies. Nudibranchs come in a wide variety of colors and sizes. Most Nudibranchs are brightly colored and between one and a few inches long.

Feeding – These two nudibranchs are very finicky eaters in that they only eat a very specific type and species of marine animal. They will slowly move around the tidepools searching to the one species of animal they will consume. It is interesting to note that each type of nudibranch will feed on a different marine organism.

Protection – Nudibranchs have a variety of protection mechanisms. The most interesting method of protection is they have stinging cells in the cerata ( appendages on the outside of their bodies ). Nudibranchs don’t actually make or grow these stinging cells themselves but actually reuse the sting cells from the animals they eat.

Nudibranchs are also brightly colored. This may seem odd for an animal trying to hide from predators. The bright colors however serve as a warning to potential predators indicating they are not as tasty as the predator may initially think. Paste experiences with these foul tasting nudibranchs are often all that is needed to deter any predator.

Ecology – Nudibranchs are marine mollusks similar to the snails and slugs found in your back yard. They have lost their shell for the most part but essentially have similar body structures. Nudibranchs spend most of their live slowly moving around the tidepool area looking for food. Hey are hermaphrodites in that they are both male and female. They can essentially reproduce by themselves or mate with other nudibranchs if available and conditions are right. They have a short live span typically less than a year.
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