Tide Pooling Log: Nudibranchs and Tunicates at Dawn
The lowest low tides come in cycles as many days in a row boast negative tides impacted by the moon’s orbit. If you’re familiar with the way the moon impacts the tides, ^(https://www.blogquicker.com/goto/https://thetidepooler.com/2023/03/23/tides-sun-moon-tide-pooling/) this makes sense.
For tidepoolers, these cycles encourage us to be on the coast every day, sometimes for almost a week straight. This summer, I took advantage of one of these early morning low tide cycles. But as I drove to South County this morning, I could feel day four of rising before 5am getting to me. This was going to be my last early morning low tide for a while.
The tides were getting later and it was just light by the time I reached the beach we had agreed to meet at. We started searching the small area we would remain in all morning, which was maybe 100 feet across.
Lately, I have come to better appreciate the common animal I see in the intertidal. The snails and hermit crabs in their millions contribute to the ecosystem far more than any unusual nudibranch I see. The blueband hermit crabs (Pagurus samuelis) were out in full force this morning. I also spied this Ventura hermit (Pagurus venturensis) resting on top of the surf grass.
This woolly sculpin (Clinocottus analis) also caught my eye. These fish can change the color of their skin to match their surroundings, but I had never seen one this bright green color before. As bottom-dwelling fish, they freeze in hopes that predators can’t see them instead of fleeing, making them excellent photo subjects.
But alas, the nudibranchs drew my attention away from these common animals. One of the group spotted this McDonald’s dorid (Limacia mcdonaldi), one of my favorite sea slugs for its bright orange clubs.
We also found this beautiful little Pacific Corambe or frost-spot nudibranch (Corambe pacifica). Another of my favorite species, they perfectly match the pattern of their bryozoan food source, but this one was surface crawling when spotted. On a kelp leaf, it reared up as if reaching for the surface again before settling down and slowly making its way across the kelp. Without bryozoan, it stood out and offered great shots. We put it near some of its food source before moving on, as surface crawling had likely brought it from a considerable way away.
As the dark clouds turned to lighter gray with the sun on their backs, we saw more and more nudibranchs, many of the usual species we see often. There were several white spotted sea goddesses (Doriopsilla albopunctata) and three-lined aeolids (Coryphella trilineata), along with other species. One in particular, the sorcerer’s dorid (Polycera atra) is known for a wide range of colorations and we got to see the full spectrum today, from all white with thin black stripes and yellow tips to nearly all black with white stripes and orange tips.
Two new-to-me species we spotted today were freckled ancula (Ancula lentiginosa) and a homely aeolid (Eubranchus rustyus). I disagree with the common names of both of these slugs. The freckled ancula is delicately blotched and speckled (although I could see how they could be interrupted as freckles) and the homely aeolid is not homely in the slightest but has quite a beautiful arrangement of cerata, if not the brightest colors.
A few other animals surprised me today. This tegula, probably the most common genus of snails in California’s intertidal, was showing off the colors of its mantle while crawling upside down. The dull brown or black shells of these creatures usually don’t even inspire a second glance, but the bright orange and black and the outstretched tentacles made even this common creature seem otherworldly. This was likely a gilded tegula (Tegula aureotincta)
A young Norris’s topsnail (Norrisia norrisii) had the same effect. Although no more than 5 or 6mm long, it has such beauty when you looked close enough.
in the Family Caprellidae
I was also surprised by a northern kelp crab (Pugettia producta) suspended midwater but for a couple limbs on algae, staring at me without moving. In a pool too small to fully submerge my camera, we found flatworms of the genus Hoploplana. On a tiny blade of surf grass I spied a skeleton shrimp, strange looking amphipods that are so thin and transparent they are difficult to get photos of.
Moving south along the rocks, we came across a niche a fellow tidepooler had explored before. Almost entirely hidden beneath an overhanging rock was a long, quiet pool. I could just barely scootch my head and shoulders under the rock to peer into this pool and found a world unto itself.
This was a microhabit, shaded from the sun’s heat and sheltered from the surf. The most prominent feature was a large swath of yellow sponge, knobby and porous. Looking closely, I spotted first one, and another, and another. Yellow umbrella slugs (Tylodina fungina) that get their color from this particular sponge were crowding over it, slurping away at their prey. False limpets with a soft shell on their backs, these are strange-looking sea slugs and seemed to materialize out of thin water on this sponge they matched so perfectly. This one was carrying a tiny brittle star on its back.
Once I got over looking at the slugs, I noticed the animals my friend had told me to look for: lightbulb tunicates (Clavelina huntsmani). The distinctive shape of these animals with their glowing centers made them recognizable even though they were a new species to me.
I had seen several other patches of unusual tunicates throughout the morning. Many clumps of mushroom tunicates (Distaplia occidentalis) peppered the tide pools with their bright purple while the jelly crust tunicates (Diplosoma listerianum) looked like they were sprinkled with glowing stardust.
Just before I had to head out, we climbing up onto some of the larger boulders more exposed to the brunt of the surf and the sun’s heat. The algae and seagrass gave way here to patches of mussels and barnacles and large swaths of anemones.
We saw many chitons on these rocks, mostly Hartweg’s (Cyanoplax hartwegii) and a few California spinys (Nuttallina californica). These rocks had distinctive, nearly perfectly round holes, some of them deep, that held other creatures that couldn’t withstand the extremes on the surface of the rock. Whether they were naturally eroded this way or bored into the rock by indigenous peoples, I didn’t know, but they looked intentional. The last animal I shot was a large California Christmas tree worm (Spirobranchus spinosus) that had made its home at the bottom of one of these pools.
The tide was creeping in by the time I had to leave and beachgoers were already here to claim their spot on a busy weekend with no idea that such amazing creatures lay just below them beneath the waves.
#Nudibranchs #Tunicates #Dawn #Tidepooler
