The Pull of the New Moon: More Tide Pooling in Seattle

 As I write this, the moon is almost new again, and we are again due to have some of the lowest tides of the summer. This month, my schedule prevents me from getting my feet wet, but I have gotten out for the last several low tides at Constellation Park, Golden Gardens Park, and Fauntleroy Ferry dock, all in Seattle. I have seen wonderful things, and also some rather horrible things. Let's start with something small and horrible.

Skeleton shrimp (family Caprellidae) are not really shrimp, they are members of a group called amphipods.

Skeleton shrimp

While fearsome in appearance, they are very small; the ones I've seen are less than an inch. Their terrifying appendages are largely used just to cling to seaweed so they don't drift away. The males of some species use their burly front limbs in fights over mates. Some even have poison glands in their front limbs - but they are not dangerous to humans. 

Also fearsome but quite small is the gaper (or horse) clam (Tresus capax).

Gaper clam siphon

Their siphon makes me think of the gaping maws of science fiction monsters, tentacles and all. And yet somehow beautiful as well, yes? Or maybe I've just been tide pooling too much. Water is drawn into one side of the siphon, oxygen and food particles are extracted, then the water is forced out the other side.

At Golden Gardens I was distressed to find a beached octopus.

Stranded East Pacific red octopus

I've never had a close look at a wild octopus before, and thought it was dead. I scooped it up in a yogurt tub with some seawater, and it promptly revived and inked! Alarmingly, the ink was reddish, like blood - but later I read that octopus blood is blue, not red. They have a copper-based oxygen-carrying molecule, which gives their blood a different hue and also helps them cope with the cold temperatures and low oxygen levels under water. While trying to get this octopus out of the tub, it grabbed my finger. It didn't hurt, but that spot on my skin felt like it had been sand-papered.

East Pacific red octopus, feeling a little better

Returned to the water, hopefully the octopus was able to recover and survive. I posted it on iNaturalist, and the director of the Rosario Beach Marine Laboratory identified it as an East Pacific red octopus (Octopus rubescens).

There are wonderful eelgrass beds at Golden Gardens and Fauntleroy. At Fauntleroy, I found this little guy and mistakenly told anyone who would listen that it was a Taylor's sea hare (Phyllaplysia taylori).

NOT a Taylor's sea hare, actually a green flatworm

Incorrect! Looking back at my photos from Golden Gardens, where I found a real Taylor's sea hare, the difference was clear.

Actual Taylor's sea hare (note the stripes and "rabbit ears")

The first guy is actually a green flatworm (Phylloplana viridis). Both have evolved the same mad camouflage skills to blend in with their eelgrass home. The sea hare, though, is a sea slug, and is more closely related to my octopus than to the flatworm! The sea hare's "rabbit ears" are sensory organs.

There were other sea slugs at Fauntleroy, though. I've never seen so many different types of nudibranchs. I really wanted to find a striped nudibranch (Armina californica), so I set my friends all on a mission looking for them. One friend found one just a few minutes after hitting the beach!

Striped nudibranch

We found dozens as time when on. Striped nudibranchs burrow into the sand at low tide, and emerge to eat orange sea pens (Ptilosarcus gurneyi) when the water returns. 

Orange sea pen (with a kelp crab - which is probably NOT trying to snack on it)

Orange sea pens are apparently a popular snack. Festive tritonia nudibranchs (Tritonia festiva) eat them as well. Some even turn orangish from absorbing carotenoid pigments from the sea pens. This fact delighted me! At brunch before hitting the tide pools, my friends had been talking about how flamingos get pink feathers from eating shrimp and other foods high in carotenoid pigments! Salmon meat is salmon-colored for the same reason. 

 I don't know why some festive tritonia were more white while others were a lovely peachy color from the sea pen pigments. Different diet? A difference in genetics? 

Festive tritonia

Festive tritonia, pretty in pink

We also found both white and pinkish frosted nudibranchs (Dirona albolineata).

Frosted nudibranch with a rosy glow

Frosted nudibranch

I couldn't find out if frosted nudibranchs also eat sea pens, but I wonder if perhaps they do, or maybe absorb pigments from other pink or orange prey.

Three of the other nudibranchs we found also had orange touches. Do they also commandeer pigments from their food sources to create their orange highlights? The bright coloration can serve as a warning to predators. Some nudibranchs even hijack toxins or stinging cells from their prey (for example, from anemones or sea jellies) to make themselves unpalatable to predators. Nudibranchs are basically tiny, cute pirates of the sea!

White-and-orange-tipped nudibranch (Antiopella fuscus)

 

Opalescent nudibranch (Hermissendra opalescens)

Possible Cockerell's dorid (Limacia cockerelli)?

While not really recommended, you might be able to emulate the piracy of these nudibranchs by eating many, many carrots - over time, your skin could take on a yellow-orange hue. Don't try to incorporate toxins or stinging cells through consumption, though. That is definitely not going to turn out well for you. Leave that to the nudibranchs.