Beach Eggs – Part 1

Cover Photo – Monterey Dorid (Doris montereyensis)

In this four-part series we’ll look at some little known wonders of the Salish Sea by examining the eggs marine critters lay on our beaches. The more I find, the more fascinated I become. Beginning with mollusks, let’s look first at those without a shell— nudibranchs (or sea slugs) and one cephalopod. The Monterey Dorid is one of a couple called a “sea lemon;” in this photo it’s laying eggs under a boulder at Kinzie Beach in Fort Worden. The eggs look like fresh pasta. At left, its feathery gills are partly submerged. Nudibranchs are hermaphroditic, and sometimes you’ll find two together.

Red Sponge Nudibranch (Rostanga pulchra)
Whenever you see bright red sponge on a boulder during a minus tide, look for the Red Sponge Nudibranch. This is one of our more colorful and tinier nudibranchs, usually only about 1/2” long. If you find this nudibranch, be sure to examine the sponge for its eggs. This smooth, oval nudibranch not only eats this sponge, but also lays coiled eggs in a lovely spiral, perfectly camouflaged right on the sponge— red with red with red. This is not the only nudibranch to lay its eggs on or near its food.

Barnacle-eating Nudibranch (Onchidoris bilamellata)
You’ll often find the inch-long Barnacle-eating Nudibranch nestled among barnacles, which it actually eats. Their mottled brown and beige tubercles camouflage them well. Here the one on the right is laying pale ribbons of eggs that look to me like a different fresh pasta. Walking along the docks at the Boat Haven one winter day, I was astonished to find aggregations of hundreds or thousands of Barnacle-eating Nudibranchs and their eggs covering many pilings. Other times I’ve found their eggs carefully laid inside an empty clamshell, with no nudibranchs in sight.

Shaggy Mouse Nudibranch (Genus Aeolidia)
Our last nudibranch is the Shaggy Mouse Nudibranch, this one with lovely long cerata, fleshy appendages, kind of like a shag rug, that serve as gills. Many nudibranchs have cerata. These two Shaggy Mouse Nudibranchs are laying masses of interlocking white eggs that look a bit like a tight labyrinth, zooming in with my macro lens. We have two Aeolidia species in our area – A. loui and A. papillosa. The adults are difficult for scientists to distinguish from photos, and their egg masses basically impossible!

Opalescent Inshore Squid (Doryteuthis opalescens)
I wish I had photos of a Giant Pacific Octopus tending up to 380 strings of white eggs that she attaches to the roof of her den. Instead here’s a photo of the eggs of a different Cephalopod, the Opalescent Inshore Squid. Two friends stopped me at North Beach to ask about strange rubbery tubes they found washed ashore. This was only the second time I’d seen squid eggs; the first time they were attached to a crab pot someone left lying on a dock at John Wayne Marina. In his outstanding guide book, Marine Life of the Pacific Northwest, marine biologist Andy Lamb notes, “The egg ‘sausages’ result from massive spawning orgies, and the diver is more likely to see these eggs than the actual animal.”

In the next episodes of Marine Eggs, you’ll see the eggs of snails, fish, sea urchins, and more!