Yellow Nudibranch, Phyllidia sp

Humans like sea slugs. They’re harmless to humans, but voracious predators if you’re a hydroid or a sponge. They come in a variety of cool shapes and sizes, and have fascinating life histories that allow one to throw around words like ‘nudi’ and ‘hermaphrodite’ with impunity in mixed company. But best of all, nudibranchs appeal mightily to humans’ attraction to pattern and color. We cannot resist taking a closer look at something bright and colorful as we explore an unfamiliar environment, such as a rocky shore at low tide.

Nudibranch are a marine invertebrate related to snails, clams, and octopuses. It does not have a shell and is brightly coloured.  Its coloration comes from the sponges it eats, and its coloration serves as a warning sign for potential predators – stay away I could be poisonous! Since their color comes from what they eat, they could range from slightly orange to almost white but are most often bright yellow. 

At the front of these Nudi's are two fleshy “horns” or rhinophores used for scent and taste reception.

These scavengers are filter feeders and also feed on sponges using their radula to file the sponge’s flesh from the rocks or other structures to which they are attached.

Like all other nudibranchs it has the ability to produce both sperm cells and eggs, which allows them to mate with any other sea lemon they encounter. This is especially helpful since sea lemons only live for about a year.