Intertidal Inhabitants

Since I was 8, I have always loved marine zoology (it felt like real-life pokemon except I couldn’t force crabs to fight each other). The most accessible ecosystem to me as a child was the intertidal – a unique and extreme habitat straddling the arid rocks and the salty depths. Since then, I have expanded my range to coastal dives.

This almanac is a running list of interesting marine creatures I have personally seen/collected/studied. There is a bias towards invertebrates and animals local to the Pacific Northwest. As a naturalist would, organisms are grouped by phylum. For a full public Google-Photos album of my photos, click here.

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An Opening Thought:

Humanity has an obsession with aliens. I wonder why the same obsession doesn’t translate to marine life – perhaps because what matters most is the existential question of “whether they exist” and not “how they work”. Intrigue precedes discovery and dies with its arrival. With aliens, we can let our imagination run truly wild, yet with even the most alien-looking marine species, 95% of our curiosity has already been satisfied through visual confirmation and knowledge of existence. You couldn’t tell me that if sea stars did not exist and we found one crawling around Mars, it would not be an instant overnight celebrity in both the scientific community and popular culture. Everyone would wonder at how such a bizarre life form functions. Yet, realistically, the only glory these Echinoderms get are “ooooh, cool shape” and “SpongeBob’s bestie”.

Let’s give our resident intra-terrestrials a deserved deep dive 🌊🐙💙.

Porifera

Leucandra heathi

Class: Calcerea

Location: Monterey Bay, CA – collected off of rocky intertidal

Yellow intertidal sponge with a single large central Ostia (water exit).

Euplectella aspergillum (glass sponge)

Class: Hexactinellida

Location: Unknown

Image Credits: https://en.wikipedia.org/wiki/Venus%27_flower_basket

Rare deep-sea sponge with a silicone-based skeletal structure (spicules) arranged in a crystal-lattice structure

Ctenophora

*a rare sight. still searching

Cnidaria

Anthopleura xanthgrammica (Giant green anemone)

Class: Anthozoa

Location: Monterey Bay, CA – Asilomar

A vibrant, solitary cnidarian sure to catch your eye on a trip to the intertidal. Their amazing color comes from the algae they eat.

Corynactis californica (strawberry anemone)

Class: Anthozoa

Location: Monterey Bay, CA – collected off of a scuba dive

A cute, vibrantly scarlet, club-tipped anemone found in great abundance off the coast of California.

Urticina lofotensis (White-spotted anemone)

Class: Anthozoa

Location: Fanshell Beach, CA

This red booger of an anemone is noted for its white spots on its stalk. Apologies for the poor photo quality, but this was a rare find wedged deep underneath a rock.

Arthropoda

Hemigrapsus nudus (purple shore crab)

Class: Malacostraca

Location: Asilomar Beach, CA – collected off the rocky intertidal

One of the most elegant and surprisingly docile members of the rocky intertidal. The claws of males can be a vibrant porcelain purple-spotted white.

Cancer producta (red rock crab)

Class: Malacostraca

Location: Asilomar Beach, CA – collected off the rocky intertidal

A juvenile with a beautiful purple-striped carapace that will grow up to be a voracious and non-picky eater that sometimes finds its way onto dinner plates.

Pugettia producta (kelp crab)

Class: Malacostraca

Location: Asilomar Beach, CA – collected off the rocky intertidal

A juvenile that keeps itself clean – a telling indicator of the species. They get their color from the kelp they eat, and when camouflaged, they are almost invisible.

Pentidotea wosnesenskii (kelp isopod)

Class: Malacostraca

Location: Fanshell Beach, CA

Do you even see an animal here? This cousin of roly-polys gets its perfect camouflage from its diet.

Mollusca

Doto varaderoensis (Doto nudibranch)

Class: Gastropoda

Location: Monterey, CA – collected off a dive

These minute nudibranchs have some of the most stunning dorsal cerata in the family. They greedily indulge on hydroids – tiny stationary jellyfish.

Ceratodoris rosacea (Hopkins red nudibranch)

Class: Gastropoda

Location: Asilomar Beach, CA – collected off the rocky intertidal

A rare but stunning sight in the intertidal. This predator gets its vibrant color from the bryozoan colonies it eats. Long, tubular, and pink-tinted cerata can make this nudibranch appear like an anemone to the uninitiated.

Ceratodoris rosacea (lined chiton)

Class: Polyplacophora

Location: Fanshell Beach, CA

Though on the smaller end of spectrum for chiton, they make up for it by being stunning. All molluscs have a mouth and “teeth”, but it’s harder to believe in this case…

Echinodermata

Ophionereis annulata (banded brittle star)

Class: Ophiuroidea

Location: Fanshell Beach, CA

These brittle stars move unlike any traditional sea star you have ever seen. They often scuttle across the floor with the speed and mechanics of a 5-armed octopus.

Mesocentrotus franciscanus (red sea urchin)

Class: Echinodea

Location: Fanshell Beach, CA

A lone red urchin amongst a sea of the more common purple urchin (purpuratus).

Patiria miniata (bat star)

Class: Asteroidea

Location: Hopkins Marine Station, CA

One of the most ICONIC intertidal inhabitants… but rarely seen with 6 arms. I have a theory that Patrick from Spongebob is named after this genus.

Platyhelminthes

Hylocelis californica (Large pacific flatworm)

Class: NA

Location: Asilomar Beach, CA – collected under rocks in deep intertidal

Flatworms are always WTF fuel. These blobs breathe through diffusion, and have a single proliferating gut. Can you see a pair of “eyes”?

Nematoda

*I had a few pictures I lost… more to come

Annelida

Syllidae – species unspecified

Class: Polychaeta

Location: collected on a coastal dive on Monterey

A hidden worm wonder that burrows about kelp roots and would go unappreciated if not for a microscope.

Terrebellidae – species unspecified

Class: Polychaeta

Location: collected on a coastal dive on Monterey

These burrowing worms filter sand for food and dead animal particles. They are known for their almost anemone-like tentacles that help them feed.

Dorvillea moniloceras (candy cane worm)

Class: Polychaeta

Location: collected on a coastal dive on Monterey

Resembling something straight out of Santa’s nightmares, this worm hates light, going into a snake-like fleeing panic when under the microscope.

Hemichordata

Schizocardium californicum (acorn worm)

Class: Enteropneusta

Location: collected on a coastal dive on Monterey

These phallic beasts are actually our closest cousin outside of our own phylum of Chordata. They sift through sand and leave poop-like strands of filtered sand.

Chordata

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