#nudibranch week

[catnoli]

a collection of tide pool critters + epaulette sharks from my ko-fi sticker sheet for september!! join here to get it ^_^

[low-po1y-princess]

One of my environmental science classmates knows Abt gwar and liked my shirt. Awesomes 👍

[octochick]

thi createure. is peak creatutre. i love iot

[televisionbug]

ms paint guys

[obsessivevoidkitten]

Love is a Many-Legged Thing

Yandere Squid Merman x Gender Neutral Reader CW: Noncon, tentacle noncon, light tentacle bondage, stalking, kidnapping, squid-based merman, big slimy prehensile merman dick, reader fucked senseless, merman fantasizes about receiving oral sex, general yandere behavior, delusional yandere, voyeurism, exhibitionism Word Count: 2k (Happy MerMay!!!! I really hope you all love the fic, would have been done weeks ago had the ac not died. But still 40min left of MerMay! I wrote this fast without a beta reader so please forgive any mistakes! The name Onyk is a reference to Onykia Ingens, a deap sea squid with an astoundingly long dick.)

Seaspark Aquarium was a very unique establishment. Not only did it contain the usual attractions that an aquarium housed, the tide pools, the sharks, a seemingly unending variety of colorful fish and corals and nudibranchs, but it also housed transient merfolk. The aquarium was situated on a flat outcrop of rocky land. Via submerged tubes it granted access to a huge tank to the ocean and merfolk below.

The tank was absolutely massive and had many different areas including a reef, a seaweed forest, a beach, and even a secluded sea cave. There were underwater cameras in most of the areas that live streamed what was happening on screens for the humans. Though the sea cave feed was restricted to adults only since the merfolk sometimes mated there.

The aquarium was just as much an exhibit for the merpeople as it was for the humans, they had underwater screens that allowed them to view the humans at play and at the food court. They enjoyed seeing and even communicating with their terrestrial cousins. There were several areas where humans and merpeople could talk face to face or via the cameras. Many of them visited quite frequently and made friendships with regular customers and their favorite staff members.

You had been blessed with landing a really good job at Seaspark Aquarium. Though it was entirely because you were the cousin of the curator of the establishment. You did janitorial tasks, including sometimes scraping the tanks, and occasionally you had to provide food for an exhibit. Even though interacting with animals or merfolk was not a common part of your job, there was one squid-man who had become quite friendly with you. Onyk.

Most of the squid type mermen shied away from human interaction, and really the aquarium as a whole, but not Onyk. He had always been a frequent visitor. A knowledgeable observer might even say it seemed that he had been hoping to find something there. The first few times he had gone had been out of pure curiosity about humans after hearing tales about them his entire life. But after his first couple of visits he was enthralled. Everything about the land walkers amazed him.

And then he met you and felt his heart flutter every single time he looked upon you. He frequently tried to engage you in conversation whenever he could and was always watching you, though often it was in secret. Onyk cherished your chats with him, he found you so interesting, even more so than he found other humans. He loved seeing you go about your tasks, it made him think of you cleaning his home as his mate while he went and got food for the two of you.

Of course if you had any say, that would never happen. Onyk, for some reason you couldn't quite place, creeped you out. No, it wasn't the head of tentacles he had in place of hair, nor the dark purple tentacles he had from the waist down, it wasn't his smile that showed off his dangerously sharp teeth, or his cyan blue eyes. No, it wasn't anything physical, just a weird energy he seemed to give off. Like a hungry animal hunting its prey.

You tried to be nice to Onyk, though you always tried to keep conversations brief and hurry on to other tasks that would take you out of his reach. Unfortunately he took your awkward stammers and clumsy rushing to zip away from him as you being extremely shy because you liked him. He sighed and stared at you longingly, head resting on his hands, as you rushed off once more. Clearly you were simply too embarrassed by your emotions to act rationally around him. Onyk had to find a way to get you to stop running off. As adorable as it was that you kept scampering off from your shyness you really needed to be closer to him.

Onyk had a brilliant, though simple, idea. It came to him right as you were in the middle of making another excuse to run away from him while the two of you were chatting in the beach area. He'd simply grab you. It wasn't the first thing he'd normally do, but you were just too prone to running off. It was more than obvious you needed him to make a firm and forceful first move.

"Well uh... it was nice seeing you again Onyk... but um... I gotta go check on the tide p-"

Onyk lunged at you suddenly with the speed and ferocity of lightning. He pulled you into the water and swiftly took you into the empty sea cave and sat you on the dry ground within. Yes, this would do perfectly for his purposes. It was a huge room that had an area for him to swim and enough space for you to run about and get exercise. This would make a lovely home for the two of you, he'd have to keep all the other merfolk out from now on but that wasn't an issue, they were respectful of claimed territory.

Once you caught your breath you were confused and angry at the sudden relocation.

"What the f-"

He interrupted you again, this time by pressing his hungry lips to yours in a passionate embrace. His long tongue slipped past your unsuspecting lips and explored every inch that it could reach. His saliva pooled in your mouth, claiming it. The offending muscle snaked down your throat before finally retreating as he broke the kiss, you struggled to find your breath once more.

"Heh, sorry for interrupting, I have just been waiting to kiss you for so long I couldn't hold back any longer!"

“What!? Why did you do that? Why did you bring me here!?”

“Well your shyness was making it hard for us to take things to the next step in our relationship, now you can’t let your nervousness get the better of you and make you run off!”

“Next step in our relationship? We have no relationship, you creep!”

“Don’t say that! Y-you just have the jitters because moving in is such a big step! Yeah, they’ll wear off soon I’m sure.”

“There won’t be a soon, I am going back to the beach!”

You started to head back to the water, but Onyk closed the distance between the two of you easily.

“But you can’t go! You’re just in denial and nervous, but you’ll love living with me, I promise. M-maybe I’m not moving too fast but too slow. That must be it, you must be all pent up and eager for my dick! So naughty~”

Onyk’s blush was evident even on his light blue skin. He swallowed your complaints in another deep kiss as he stood behind you and rubbed your crotch gently.

“We’ll do it in front of these cameras so everyone knows you’re mine now~”

And, indeed, the screens in the adults only section of the aquarium definitely picked up some viewers as the scene between you and Onyk unfolded.

Most mermen would have had trouble traversing land, but Onyk’s strong tentacles allowed him to maneuver easily enough. He peeled off your wet clothing and wrapped his arms tightly around your bare chest, rubbing and caressing you with greedy hands. His prehensile cock wrapped partially around your waist, held you close as it rubbed against you. At first you mistook the sensation for a tentacle before looking down and seeing it, the cock was tapered, icy blue and glowing at the tip, with the rest of it being dark purple.

Your shouts and screams were ignored as Onyk convinced himself they were just you being grumpy or maybe playing hard to get. The merman’s sharp teeth bit carefully at your tender neck as you squirmed. Most of his tentacles had wrapped around your legs, powerful suction cups firmly adhered them to you. They held you staunchly in place despite your best efforts to struggle.

The remaining two writhing appendages were busy with another task. They gently prodded and massaged your tight hole, slowly worming their way inside you. Your efforts to clench and keep them outside of you were rendered futile as they finally worked their way inside of you. They began thrusting in tandem back and forth within you, loosening you up well.

Your next attempt at protesting devolves into several lusty moans as he ministrations begin to elicit pleasure. It’s all the confirmation he needs that he has been right all along and definitely went about everything in the right way.

“Your mating sounds are so lovely,” he said as he nipped at your ear.

His tentacles suddenly withdrew from your lovingly stretched hole, leaving you involuntarily whimpering at the sudden removal.

“Awe, don’t worry, love. I have something far better to put into you~”

You snap out of it when you hear those words and feel his cock move itself from your waist and start wiggling against you in search of its target.

“What!? No, please do-oooh~ Aaah!”

When it found your entrance it deftly slithered right in. Much to your unwilling pleasure.

Onyk chuckled.

“I knew you just needed some good dick~ You feel soooo good. You were made for this!”

When you happened to look up at one of the cameras you blushed and looked down. The room that monitored the sea cave was now packed, everyone enjoying the sight. The aquarium was already at work recording with plans to put it on their website for sale.

You couldn’t help the lewd cacophony of noises that tumbled from your mouth as the thick slimy cock thrust back and forth inside of you.

“I love you. I love you. I love you. I love you. I love you. I love you. I love you. I love you. I love you!” Onyk chanted louder and louder until he slammed into you hard, filling you up with warm viscous semen at the same moment that you were shuddering from the strongest orgasm that you had ever experienced.

You were far too dazed and overstimulated to realize what was going on in that moment or what you were saying, but on autopilot you mumbled back what your brain thought it was supposed to when someone told you that they loved you.

“I l-love you too…”

Onyk was overjoyed to hear those words from his beloved human. He pulled out of you and laid down on the floor of the cave, pulling you close to him and resting your head on his chest. His webbed fingers gently caressed you as did both the tentacles that made up his "hair" and the ones below his waist. Cum slowly ebbed out of you and onto him but he didn't mind, the two of you would just get messy again the second you came to your senses. He nuzzled into your hair and gave you dozens of little kisses. Your mind was too blank and your body too exhausted to do anything but drool a bit on his chest while he cuddled you.

His head was swimming with all of the things the two of you would do together. Sharing meals, chatting, mating. He couldn’t wait to wrap his cock gently around your neck while at the same time plunging it down your throat and having that pretty mouth of yours suck it until he was feeding you his cum. Maybe the two of you could try it when you woke up.

Meanwhile onlookers on the viewing screens were putting away their cocks and slipping their fingers out of their pussies with the spectacle now over, but word soon spread and tourism was up over 300 percent! Scientists the world over were interested in documenting this rare species of merman having sexual relations with a human. Grants were given. A great raise and credit to your cousin, the curator.

It was even considered a diplomatic victory for merfolk and humans!

Everyone came to the consensus that on all fronts, but yours, it was far too beneficial and lucrative to make sure you had to permanently stay in the sea cave for the rest of your life with Onyk. At the very least they equipped the habitat with amenities like a proper bathroom, tv, video games, and human food. The sea cave area was also expanded, and you were afforded some privacy, except for most of the times that your “husband” Onyk was spilling his seed into you. That’s what people wanted to see.

[protectoursharks]

Hiii!

I'm like a week new to Tumblr- I can't figure out how to sort through content well, so you've probably posted about this before

What do you know about sea slugs?? Like particularly interesting ones! I love them and wanna hear your description!!

Here are some of my past nudibranch posts: x x x

One of my favorite nudibranchs is the Sap-sucking sea slug (Cyerce elegans)!

The large leaf-looking parts are known as cerata and help the nudibranch "breathe". They can also be released to use as a distraction if the animal feels threatened!

The species has many color variations, from nearly transparent to red or brown! The color is dependent on the environment in which the species is found; these nudibranchs have coloration that matches the local algae that they eat. This helps them stay camouflaged while they're eating!

[bluebudgie]

And it's live!

The Interstellar Invertebrates enamel pin Kickstarter campaign has launched today and will be running for 30 days until October 12 2023, 2:00 pm CEST.

For all lovers of spineless creatures this hard enamel pin collection features designs of five different animals: The rubber ducky isopod, the common cuttlefish, the nudibranch willan's chromodoris, the western honey bee and the moon jellyfish.

Have a look at the small test batch of rubber ducky isopod pins I ordered ahead of the project:

For more info check out the campaign page here!

---

And a big thank you to everyone who shared the project's pre-launch page in the past week, it means a lot! <3

[thicctails]

><((((º>‿︵‿︵‿︵Undercurrent‿︵‿︵‿︵<º))))><

A Merformers x Reader Fanfiction

Chapter 2 ° Coastguard

Blessed be Randy the coffee machine, your holy god of caffeine. May His hazel liquid flow eternally into graceous Bartholomew, vessel of Randy's divine lifeblood; discount noname brand coffee that had expired last week.

Taking another sip of your beloved breakfast drink, you forced yourself to walk towards the greeting area of your clinic, praying to any deity that was listening that you looked at least passably presentable. You'd taken far longer to pull yourself away from the tender embrace of your nearly flat air mattress than you should have, and both your nerves and back were paying for it.

The head researcher of A.E.R.O. was meeting with you today to discuss your collaboration effort with them, and finally tell you exactly what species you'd be getting to work with. You hoped it would be something exciting, like sharks, dolphins, whales, or nudibranchs.

Taking a shaky breath, you shoved your anxiety down into the pit of your gut where it could, hopefully, only be noticed by you as your hand grasped the handle of the door. You pulled, ready to take the first proper step towards your new life.

Ka-thunk!

Ah. It was a push door.

Willing the colour that had suddenly flooded your cheeks to kindly fuck off, you meekly pushed the door open.

A man was standing in the main entrance room, leaning against Desk the desk and scrolling through something on his phone. He was dressed fairly casual for someone in his position, sporting tan cargo shorts, a forest green t-shirt, and a black lab coat, his company's acronym emblazoned in crisp vinyl across his breast pocket. He had tousled light brown hair and deep brown eyes that were framed by square glasses. At the sound of your approach, he lifted his gaze from his cellphone and gave you a warm smile, pocketing the device and turning his body towards you.

"Doctor L/N! It's nice to finally meet you!" he greeted, extending his hand to you. "My name is Dr. Burns, but please, just call me Graham."

Though it had been difficult to tell sometimes, you had not actually been raised by a pack of rabid wolves, so you returned the gesture, gripping the man's hand and giving it a shake.

"It's a pleasure to acquatence your make."

Oh, Jesus Christ.

Hey, God? Could you do a little smiting? Yeah, right here please.

"I- I'm so sorry, I swear I didn't mean to say that." You managed to get out, almost shocked that you hadn't fucked that sentence up as well.

Breaking News! Local PhD holder flubbs basic greeting! Becomes World Champion speedrunner for ruining first impressions and instantly loses any chance of being considered for further employment and any shred of respect this man had for them!

"It's fine. Honestly, I was just as nervous as you when I first started." Graham laughed, startling you out of your own mental spiral, "I was so preoccupied with my own worries that I tripped and fell face first into a pool on my first day."

You stared at Graham for a moment, stunned that he was still talking to by choice and not out of obligation, before a small, strangled chuckle left your throat, sounding more like the dying squak of a strangled seabird than a laugh.

"Come on, the rest of the team is waiting for us in town." the brunette said, gesturing for you to follow him.

You arched a brow but obediently followed after him, trailing after the researcher like a duckling waddling after a pair of boots.

"Oh? I was under the impression this meeting was to discuss my contract." you replied, trying to scrape together a professional-ish sentence while simultaneously praying that you weren't coming off as rude.

"It is, but once everyone got wind that we would be working with someone new, they got a little," he paused, hand waving about as he searched for the right word, "excited. It's been a while since anyone besides Marissa worked close enough for us to talk to them on a semi-regular basis."

"Can't wait to meet them!" you said cheerfully, lying through your teeth.

The idea of having to interact with another human being today had been draining enough, but to have to converse with several? When their opinions of you could impact your career?

Your hands twitched around Bartholomew's smooth, ceramic body, wishing you'd added a few ounces of pure caffeine to your coffee. Maybe you'd get lucky and get struck by a bus.

Unfortunately, God wasn't known for being kind to you, so you arrived at a small diner completely unharmed.

The worn bell above the door dinged as you and Graham stepped inside, the smell of greasy fries and cheap burgers wafting all around you as he led you over to one of the booths, the cracked red leather seats occupied by three other people in various states of dress.

There was a younger woman with russet skin and shockingly red hair that was pulled back in a loose ponytail, a few hairclips keeping her bangs out of her bright blue eyes. She was dressed in a cream and light orange dress, matching knee-high boots complementing her outfit. She was scrolling on her phone, but put the device down when she noticed your approach.

Ah, the mortifying feeling of being known. It never failed to make you uncomfortable.

The other two, who were seemingly in the middle of seeing who could chug a milkshake faster, were men, light skinned and with almost identically brown hair. It was easy to pick them apart, though, seeing as one was built like a brick shithouse and looked as though he was cosplaying some strange cross between a soldier and a Ghostbuster, and the other was a twink that also happened to be absolutely rocking some sun-bleached overalls and a set of the most obnoxiously yellow rubber boots you'd ever seen in your entire life.

"Hey, dingbats!" the woman hissed, nudging her closest colleague, who happened to be the rubber boots guy, "The new vet is here!"

While the two guys attempted to swallow their drinks without getting a brain freeze, Graham gave you a somewhat sheepish smile. "Dr. L/N, I'd like to introduce you to Doctor Sari Sumdac, Doctor Spike Witwicky, and Doctor Blaine L. Parker."

"Mainframe." Blaine said, slamming his cup down with a satisfied sigh, "Call me Mainframe. Only my Mama calls me Blaine."

"I'm still good with Spike." the other man chimed in, extending his hand to you as you and Graham slid into the opposite booth seat. You shook it, quickly repeating the action with Sari and Mainframe.

"So, you're the new guy, eh?" Mainframe asked, "We've been waitn' for Marissa to finally pick someone. She's too picky, if you ask me."

"Not picky enough if she hired you." Sari shot back, and for a moment you stiffened, afraid you were about to have front row seats for a fight, but Mainframe's laughter and Sari's teasing expression quickly calmed your nerves. She looked back at you, her face taking on a more genuine look, "He's not wrong about us waiting, though. A.E.R.O. has been around for a few years now, but you're the first vet we've gotten assigned to work with us."

Your eyebrows shot up, mouth opening slightly in surprise before you remembered to shut it, "Really? Why?"

The gathered marine biologists looked at each other for a moment, before Spike leaned in closer to you. You matched his action, wondering what exactly he had to say.

"Did Marissa fill you in on what exactly A.E.R.O. means?" he asked in a low whisper.

You thought for a moment, then shook your head. Actually, your employer had told you very little, just enough to get you to sign a contract with her. You didn't regret your decision; anything would be better than the place you'd come from, but this secrecy did make you wonder what exactly you'd gotten yourself into.

"A.E.R.O.," Spike continued, "stands for Aquatic Extraterrestrial Research Outpost."

You blinked, leaning back as you turned over what Spike had just told you. Had you heard him correctly? No, surely not. Clearly you hadn't had enough coffee yet.

"I'm sorry," you apologized, chuckling a little "I must still be a bit groggy, because I thought you said extraterrestrial for a moment there."

The four shared another look, then once again focused their attention back on you.

"You heard correctly, Dr. L/N." Graham said, producing an envelope from the interior of his jacket. He quickly glanced around the diner, before sliding the envelope over to you. He continued speaking as you picked it up, hands shaking slightly.

"Five years ago, several objects from deep space suddenly entered our atmosphere and crashed into the Atlantic Ocean. It was presumed that they were abnormal meteors of some kind, but a government owned dive team discovered that they were actually pods of some kind, made of materials not found on Earth.

"They were empty by the time they were found, but not long after they were discovered and retrieved, strange signals began to be picked up by sonar sensors, and sailors around this area began to report seeing bizzare creatures swimming beneath their boats, some of them claiming that their vessels were attacked, which was corroborated by several documented cases of boats coming in with scratch marks on their hulls."

You opened the envelope and reached inside, withdrawing several polaroid photographs. Each one was of a different boat, ranging from dinky little sailboats to bulky fishing trawlers. However, they all shared one unique feature; a set of deep gouges that tore through wood and metal, left behind by something that had to be absolutely huge.

Well shit, slap a tinfoil hat on your head and call you a believer, because there wasn't much in the ocean that had claws to begin with, and certainly nothing with claws large enough to do that kind of damage.

As you began to tuck the photos back into the envelope, you noticed that one of them was drastically different. It was blurry, taken on the coast during what looked like a storm, but not even those hindrances could mask the appearance of the... thing that had been captured on camera.

It was big. Like, really big.

The closest thing you could compare it to would be some kind of whale, but it looked so wholly unlike any species you knew of that you immediately tossed that idea out the window. It had a long, silvery body, covered in large, armour-like scales that almost gave the appearance of it being segmented. Thick, spiny fins jutted out along most of its tail, purple webbing torn and ragged. It's upper half was obscured, as the creature was diving back down beneath the surface, but the very beginnings of its torso hadn't quite been submerged when the photo was taken, and you could see a long row of crimson gills that glowed in the moonless dark.

"What the fuck." you breathed out, shoving the photos back into the envelope before tossing it away from you like you were playing the world's strangest game of Hot Potato.

"Yeah, that was pretty much our reaction too." Sari said, picking up the envelope. "We've been calling that one 'The Meg', since you could almost mistake it for an overgrown shark, if you only caught a glimpse of it.

You pinched the bridge of your nose and groaned softly as you considered everything you'd just been told.

"Let me get this straight," you started slowly, dragging your hand down your face before resting it on your chin, "You and Marissa want me to find a way to study and treat a highly aggressive, barely studied, extremely dangerous alien, let me repeat that for you, alien species with no prior experience and, since you four work at a separate facility, no team?"

A pregnant silence met your question for a moment, before being broken by a very timid, very nervous "Yes?" from Graham, who was rubbing the back of his head.

You looked at him, looked at the rest of his team, looked at the exit of the diner, and considered your options; accept this batshit insane, borderline suicidal offer and risk getting torn limb from limb by sea monsters from beyond the stars, or move back in with your parents.

"Well Christ on a bike, sign me up." you replied, before snagging the nearby coffee pot and, after checking that it wouldn't give you third degree burns, chugged the whole damn thing, determined to get enough caffeine in your body to drown out that little voice in your head that alway nagged that you should have been a lawyer.

[shirecorn]

waiting on a mermay order?

Here's how it's going

Fish:

hell yeah I love fish. Most of you who ordered a fish have received it via ko-fi message. If I haven't done your fish yet, I'm working on it. These are easy and it's simply a matter of sitting down and doing it. I usually only sketch once and take the first thing I draw straight to finish.

The glass fish is on the backburner because i have to finish designing mermaid internal organs before I start.

Sharks:

These ones take slightly longer because I have to test out a couple different tricks to make the face look right. They've all been sketched at least. Also they are not ray-finned fish, and thus their mermaid counterpart is an imitation of their physiology rather than an offshoot from it.

Mollusks (octopus, squid, cuttlefish, nudibranchs, clams):

I had to design a new humanoid from the ground up, since these are not vertebrates and therefore can't be mermaids, as mermaids are evolved from fish. I did a couple hours of visdev the last few weeks, and have finally figured out a body plan I like. Since I know what the gimmick is, I can start on the individual species ordered and draw from sketch to finish just like the mermaids.

Arthropods (all the people who wanted crabs and shrimps):

Yet another creature I have to build from the ground up. I need to do a lot of visdev to get to a point where I can start. Every time there is a new phylum introduced, I start from scratch.

Seals:

Just a matter of starting! These will be selkies. I need to draw both a human form and a seal form, so it's double the work. I tend to prefer fish for that reason.

If you would like to see works in progress, my visual development process, realtime worldbuilding, and see fresh mermaids as soon as they are done, check out my discord!

[uncharismatic-fauna]

Common Acorn Barnacles on Call

Semibalanus balanoides, more commonly known as the common acorn barnacle or the northern acorn barnacle, is a widespread species of barnacle found all along the Pacific and Atlantic coasts of North America and the intertidal zone of Europe-- though it is notably absent from the Bay of Biscay. Its range is limited by the temperature of the water in which it breeds; in the winter, they require water as cold as 7.2 °C (45.0 °F), but throughout the rest of the year they can tolerate much warmer climates.

Like many barnacle species, S. balanoides is hermaphroditic, meaning it has both male and female reproductive organs. Once the water reaches the optimal temperature, typically in November or December, the barnacles begin to breed. An individual will reach out with a penis that can be up to 7.5 centimetres (3.0 in), and inseminate a nearby barnacle; this process may be repeated up to eight times between a single pair. After insemination, the penis disintegrates to be regrown the following year.

In the meantime, the fertilized barnacle will produce up to 10,000 eggs that are stored in a special sac within the shell cavity. The common acorn barnacle releases its eggs between February and April, in concert with warming waters and the spring algal bloom. The eggs then hatch into miniscule larvae, which spend several weeks feeding on plankton in the water column and going through a series of molts. Following the sixth molt, the larvae stops feeding and seeks out a suitable place on which to anchor itself. Once it has found a surface, the larval barnacle 'crawls' along the surface until it encounters one of its own species. At this point, they will attach themselves with a cement-like glue which is capable of supporting up to 3,200 kg (7,000 lbs) Here, a single northern acorn barnacle may live anywhere from one to seven years.

Adult S. balanoides are identified by the white, six-sided limestone casing with which they protect themselves. However, one unique feature of this species is the way in which they attach themselves to their chosen surfaces; unlike other barnacles, which have a hard calcified shell base, the northern acorn barnacle has a membranous base. Within their shells, they have rather soft bodies, including a set of feathered appendages called cirri with which they use to breathe and collect food.

The common acorn barnacle is a filter feeder, consuming microscopic plankton and bits of detritus from the water column. Though their hard shells deter most predators, adults are vulnerable to other predatory invertebrates like dogwelks, nudibranches, and sea stars, as well as fish like the shanny that are specialist feeders of barnacles.

Conservation status: The common acorn barnacle has not been assessed by the IUCN. The species is extremely common and very resilient, and in fact has been in existence since the Jurassic period. However, rising ocean temperatures may negatively affect their breeding period.

If you like what I do, consider leaving a tip or buying me a kofi!

Photos

Neil DeMaster

Oregon State Parks and Recreation

Kim Hanson via Wikimedia commons

[catnoli]

lil epaulette and sea bunnies hanging out 🫧☁️🦈 the 9 month reward sticker for silly society members!! it’s going to be a clear sticker and im so excited to see how it turns out!! it’s so exciting especially because weve reached over 100 members in silly society, thank you thank you thank you ^_^ check out silly society here!

[plaguedocboi]

Does your aquarium workplace have any protocols on handling animal species that might be difficult to feed due to finicky preferences? Lets say the team offer it foods A, B, C on day 1 then if rejected, D, E, F on day 3. I recall you were saying you managed to figure out what the moon snails feed on! My lab is stuck with a few nudibranchs from live rocks which we intend to return to the supplier but our prof is adamant that we try something first for a week :/

We basically just keep trying until we find something that works. Mollusks are strange little guys tbh, I’ve found that they either accept everything you give them or they’re extremely picky and it varies between individuals. They are also easily stressed and might stop eating for a while if they’ve been through a difficult time (say, getting shipped to a new home).

Nudibranchs often have very specialized diets, for instance there are species that exclusively feed on barnacles or certain types of algae, so I recommend identifying the species and doing some research to see what they’re known to eat. If they still refuse, it may be best to just return them. Luckily mollusks tend to have pretty slow metabolisms so they can frequently go a few weeks without food.

[rnbwtrout]

Woe, Splatoon OC sketch dump be upon ye. Alby (Inkling) is mine, Isla (nudibranch) and Davy (octoling) are my friends'. Band name pending. The drawing with the roller is before I added more design details haha

Supposed to be on hiatus but I had gone like two weeks without drawing and I went feral today and drew like 7 pages in my sketch book

[wikipediapictures]

the nudibranchs are coming back this week 🥰

[man-i-love-molluscs]

Hi!

In the UK, last week was biology week and I REALLY wanted to get this finished to celebrate. Unfortunately, I have been incredibly busy with coursework and only managed to finish this up yesterday. So, for my sake, imagine this was posted last week. Without further ado:

——————————————————————————

Dinoflagellates

Superclass- Dinoflagellata

Pictured: Ceratum lineatum

Dinoflagellates are plankton belonging to the superclass “Dinoflagellata”, a clade containing aquatic algae. Though often found in marine environments, dinoflagellates can be found in almost all aquatic environments. They are the bottom of most aquatic food chains and are responsible for many natural phenomena, like glowing beaches and even potentially one of the great plagues of Egypt!

Pictured: an anatomical diagram of a dinoflagellate

Dinoflagellates are covered by a theca (sheath) that can be either plain or ornamented and have two flagella (tails). One is a longitudinal flagella which propels the dinoflagellate forward and the other is a transverse flagella which provides spin to the algal cell.

Pictured: glowing shore caused by dinoflagellates

So, about glowing oceans, they’re caused by some genera of dinoflagellates that contain “Scintillons” which are, essentially, cellular glow sticks. Dinoflagellates light up when they are contacted, causing beautiful displays of light on turbulent shorelines. This bioluminescence is thought to be a response to predation. It sounds strange, producing dazzling light to deter predators, but the lights aren’t to repel predators, they’re to attract the predators of the predators. Like setting up a giant neon sign saying “This guy is eating me and they’re REALLY tasty”. They tend to build up in warm lagoons with limited access to the open sea and glow a bluish colour. Dinoflagellates produce a compound called “luciferin” which reacts with an enzyme called “luciferase”, and this reaction is what causes the light.

Pictured: a coral reef

Aside from being rave algae, dinoflagellates also form symbiotic relationships with many different organisms. Sponges, molluscs and some bacteria just to name a few, they form so many that the family they lie in is called “symbiodinium”. The most notable- though- is their relationship with coral. Coral as we know it is composed of coral polyps and dinoflagellates- or zooxanthellae as those able to form symbiotic relationships are known colloquially. In these relationships, zooxanthellae offer amino acids and products of photosynthesis and in return get carbon dioxide for photosynthesis as well as phosphates and nitrates. Colonies of coral polyps and zooxanthellae comprise coral reefs, responsible for upholding many tropical ecosystems in our beautiful oceans. When these colonies experience high environmental stress, the polyps will expel the zooxanthellae, resulting in coral bleaching, where coral reefs lose their colour and die; Coral bleaching is also a major problem our oceans are facing due to factors like ocean acidification and pollution.

Pictured: Pteraeolidia semperi

Zooxanthellae also form symbiotic relationships with nudibranchs, specifically aeolid nudibranchs from the genus Pteraeolidia; aeolid nudibranchs are those with long tubules sprouting from their backs, those in the genus Pteraeolidia look comparable to Christmas tinsel. In these relationships, the zooxanthellae live in the nudibranchs’ tissue and supplement their diet with photosynthetic products. For more information, look into the work of Professor Ove Hoegh-Guldburg and Professor Rosalind Hinde.

Pictured: a red tide

Dinoflagellates also are thought to have caused one of the 10 plagues of Egypt. Dinoflagellates are known to cause “red tides”, where masses of algae grow on the surface of water. Red tides do crazy evil things, like killing fish, making shellfish poisonous and even emitting toxic aerosols that cause burning sensations in throats and noses. Stalagmite records show that during the plagues, Egypt experienced a great drought. It is thought that this drought caused an algal bloom in the river nile, causing water to become undrinkable, fish to die and amphibian numbers to boom before they escaped the river. It’s important to note that while dinoflagellates are a kind of algae that is known to bloom in this way, some evidence points to algae that do not belong to the superclass dinoflagellata as the cause of this plague. Regardless, the marriage of religion, history and biology is very interesting.