Bremerton, WA – Salish Sea beaches can seem inhospitable… with cold, uneven rock, slippery slimy seaweed, and unidentified blobs of gushy, stinky glop smeared and dolloped here and there. I must admit that I once preferred the wild open ocean where the pounding surf regularly scours the beach and pummels loose pieces into fine sand. Wind and spray, foam and wave, vigorous plants and animals who use external challenges to grow stronger… So invigorating!
And yet there is quiet delight in the inland waters. The incoming tide creeps rather than roars, supplying the perfect home for more delicate marine creatures. One of my favorite finds of all marine animals is the fringy creature known as the nudibranch. Stranded on the beach as the tide recedes, it is easy to dismiss as a small piece of gushy tide debris, but once the water begins to lift and wave feathery rows of fragile cerata, this “blob” transforms into a spectacular little creature gliding through its space with supple elegance. It seems out of place in a world full of snapping crabs and predatory snails who slurp innocent clams right out of their homes.
Nudibranch means “naked gills” for when fully grown, they have no protective shell, menacing claws, or a fast get-away mechanism. They are exposed and vulnerable so it seems reasonable that they would not last long in the unforgiving world of ever-vigilant predators. In a twist of irony, nudibranchs actually have few predators because they are designed with some clever abilities, so don’t count them out just yet.
Nudibranchs are considered sea slugs, and the two most common groups of nudibranchs are the dorids (sea lemon, barnacle eating dorid, etc.) and aeolids (shaggy mouse nudibranch, opalescent nudibranch, etc.) The two groups have different body shapes and feed differently. One thing many of them have in common is the bizarre ability to ingest unpleasant or dangerous cells derived from their food and use them for their own coloring or defense.
For instance, aeolids like the Shaggy Mouse Nudibranch eat the tentacles of soft bodied animals such as anemones, soft corals and jellyfish. In so doing, a nudibranch is not only able to hide in the folds of the animal it is eating, but it is unaffected by any chemical toxins meant to sting. In an unexpected maneuver, the nudibranch swallows the stinging cells without triggering them, then moves the cells to the tips of its own cerata to deter predators.
Dorids eat sponges and carry out a similar process with bad tasting or poisonous sponge chemicals. Their bodies are not covered with fringe, but they also have horn-like rhinophores to sense prey as well as gills on their backside for breathing, digestion and defense. Dorids are usually oval in shape and far less flashy than their aeolid cousins.
After all these tricky acrobatics, it is a shame that nudibranchs are such short-lived wonders. Some live up to a year, but others only live a few weeks. There are over 3,000 species world-wide in a vast variety of exotic colors and patterns… they are truly a thrill to find above or below the water.
When you track wonder, remember that good things often come in small packages, so be sure to slow down and take notice of little blobs and smears… you just might discover a delightful treasure.
Cultivate Wonder… Discover Design
Where and When – When tracking animals, think about what each animal eats. If you can find their food in abundance, you can often find them. Nudibranchs eat soft bodied creatures so when you see anemones, cucumbers, floating jellyfish, etc. keep your eyes peeled for Nudibranchs. The Opalescent Nudibranch is often found under Moon Snail egg cases where they like to munch on eggs. Be sure your hands are sunscreen/lotion/soap free and wet them with sea water before touching any sea creature to minimize risk to the animal.
Carefully investigate gushy blobs and if the blob happens to be in a pool, gently move it under the water to see a beautiful and surprising transformation. However, you may be placing it in harm’s way, so be sure to put it back exactly where you found it as it was probably there for a very good reason. They are often near their food source.
Dorids that look like lemons (Monterey Dorid and Sea Lemon) are fun to find. The Sea Lemon has a faint citrus or fruity smell. Barnacle Eating Dorids like to lay their eggs on large stable surfaces like big rocks. When exploring the creatures on and around the structures of a marina or dock, watch for nudibranchs floating by, twisting and turning as they go.
Wonder Triggers for Young Trackers
- Finding sea slugs on the beach is like a treasure hunt. You have to be patient and look carefully at the details. It is best to try to see sea slugs in tide pools where they are already under water and their cerata are swaying in the current. Before you touch any sea creature, make sure your hands do not have soap, lotion or sunscreen on them, then dip them in sea water.
- Sea slugs often have beautiful colors and designs. As you study them, try to find one color that is especially striking. Think of where you have seen the color before, then make up descriptive name for the color, like “sunset orange” or “bunny nose pink.” Do you think colors help the sea slug in any way?
- Watch nudibranchs and dorids move. You may see them on rocks, in tidepools or even floating in the water. How do they move? How fast do they move? Do they turn sharply or move primarily in one direction?
References and Resources
Kennedy, J. 2018. 12 Facts About Nudibranchs. Thoughtco. Accessed May, 2018.
Dunagan, C. 2015. Amusing Monday: Sea slugs bring color to Puget Sound. Kitsap Sun. Accessed May, 2018
Images – SPegany, Copyright 2018