Portuguese man-o-war

A Portuguese man-of-war (Physalia physalis) washed up on a beach. Photo by Dr. Alex Mustard, more can be found at www.amustard.com

Domain: Eukarya
Kingdom: Animalia
Phylum: Cnidaria
Class: Hydrozoa
Order: Siphonophorae
Family: Physaliidae
Genus: Physalia
Species: Physalia physalis

It’s summer time, the time of year I get to listen to the “jellyfish invasion.” Now, don’t get me wrong; jellies are increasing in number, and there are concerns about their large populations. However, Portuguese man-o-wars are not jellyfish—they’re siphonophores!

Siphonophores are the misunderstood cousins to jellyfish, especially Physalia physalis. Jellyfish are typically a single individual with a polyp stage. Siphonophores are a colony of individual organisms called polyps, and each group of individuals does a specific job for the colony.

Portuguese man-o-wars are made up of four separate polyps: the sails, the tentacles, the digestive organs, and reproductive system. Imagine that you and three of your clones, called zooids, live in an RV together. You are in charge of driving the RV, one clone is in charge of gathering food to feed everyone, one is the cook, and the other is responsible for replacing damaged or missing zooids. Without one of your clones, everyone in the RV would die, and RV would eventually stop moving. Same can be said about siphonophores and P. physalis.

The pneumatophore is the gas-filled bladder at the top; it’s the purple-bluish structure you can see floating on top of the water. This zooid is responsible for the colony’s movement. However, the gas-filled bladder works more like a sail; the wind and surface currents do the actual moving of the colony. This is how they got their name, because the gas-filled bladder resembled the sails of man-o-wars, a type of naval ship.

The tentacles are another organism, or zooid, of P. physalis. On average, the tentacles can extend 30 feet below water, but a single colony was recorded with tentacles as long as 165 feet! The tentacles contain venom-filled nematocysts, which they use to paralyze and capture prey. Portuguese man-o-wars feed on fish, shrimp, and other small creatures.

Gastrozooids are the polys in charge of digesting the prey and distributing the nutrients to the other polyps in the colony. Essentially, they are the digestive system of the colony. Unlike the sail and the tentacles, they have no distinctive “structure” on the colony, so they can’t be identified in a photograph.

The last type of zooid is responsible for reproduction. These polyps create other polyps for each of the groups, replacing those that have died or have been damaged. They are also responsible for exchanging genetic material with other Portuguese man-o-wars.

Portuguese man-o-wars are found in tropical and subtropical waters, and they can be found floating in large numbers—even in the thousands. I know in the US every summer, media warns the East Coast about these siphonophores washing up on public beaches.

P. phyaslis can be harmful to humans. I’d hate to be out swimming and get stung by the long tentacles! While live man-o-wars can be harmful to swimmers, dead ones are also a concern. While the venom is rarely fatal, it hurts worse than an army of wasp stings, and the nematocysts can still sting humans after death. So if you seem a dead one wash up on the beach—DON’T TOUCH IT!

If you notice Portuguese man-o-wars in the water or washed up, notify the lifeguards and everyone around you immediately. If you’ve been stung, do not use urine or vinegar on the inflamed area.

Dive manuals suggest that you carefully remove any remaining tentacles and flush the area with sea water, never fresh water. As soon as possible, immerse the affected area in hot water of at least 112°F for twenty minutes. This will denature the toxin and break up the chemicals.

I have never seen a Portuguese man-o-war in person despite living on the eastern coast of the United States and frequenting beaches in the summer. However, I don’t think I’m terribly upset with the idea, because with my luck, I’d get stung! Siphonophores are pretty interesting, though, and I can’t wait to share more with you!

Links and sources:
Reef Creature Identification Florida Caribbean Bahamas 3rd edition by Paul Humann, Ned DeLoach, and Les Wilk ⇐had the info on how to treat the sting
https://www.nationalgeographic.com/animals/invertebrates/p/portuguese-man-of-war/ ⇐in-depth look into the sections of the man-o-wars
https://oceanservice.noaa.gov/facts/portuguese-man-o-war.html ⇐simplified info
https://www.britannica.com/animal/Portuguese-man-of-war

Mushroom Coral

Domain: Eukarya
Kingdom: Animalia
Phylum: Cnidaria
Class: Anthozoa
Order: Scleractinia
Family: Fungiidae
Genus: Fungia
Species: Fungia scruposa

Do you know what gets my attention? An old article about a species of coral that was documented eating jellyfish. But I’ll get to that later; first, I want to introduce you to Fungia scruposa, or the mushroom coral!

Found in the tropical waters of the Red Sea, Indian Ocean, and western Pacific Ocean, mushroom coral are unique for a few reasons. Unlike other hard corals, F. scruposa lives as a single individual instead of as a colony, much like the Atlantic mushroom coral of the family Mussidae. Don’t let their similar common names fool you, though. These two corals are not closely related to each other.

Juvenile mushroom coral start out as raised disks that attach to dead coral or rock. When they grow to about an inch in diameter, they detach themselves from their substrate. However, this does not mean that they’re super mobile. Instead, mushroom coral typically stay in the same area and inhabit the sediment or rubble.

But what happens if a strong wave comes through and turns them over? Fungia scruposa use their tentacles to right themselves when knocked over by waves or by another animal.

Mushroom coral get their name from their appearance. They have an irregular disk shape that is about 1 inch in diameter, sometimes a little larger. At the center of the disk is a raised mound with a deep-looking cut, which is the polyp’s mouth. The coral’s hard exoskeleton has several thin ridges that spread out from the center, making it look like the underside of some mushrooms.

Fun fact: did you know that the ridges on the undersides of mushrooms are called gills?

I’ve yet to see this coral while diving, but I absolutely cannot wait! Mushroom coral are unique for their class, because they live as solitary polyps and spend their adult lives not attached to anything. But on top of all that, they were also recorded eating whole jellyfish in the late 2000s—something that was completely unheard of!

There are some species of sea anemones—distant cousins to coral—that are known to eat jellyfish. However, these are the first hard corals that scientists have seen eating jellies. Unfortunately, the divers were only able to see the jellies disappear into the mouths of several mushroom coral, but they could never see how the mushroom coral captured the moon jellies. Still, it’s absolutely fascinating and may prove how resilient hard coral can be in a changing ocean environment.

And maybe you can be the researcher that discovers how they do it! Maybe you can discover more species of coral that will dine on jellyfish when the opportunity presents itself.

Sources and links:
Ocean The Definitive Visual Guide made by American Museum of Natural History
http://www.coralsoftheworld.org/species_factsheets/species_factsheet_summary/fungia-scruposa/
http://news.bbc.co.uk/earth/hi/earth_news/newsid_8350000/8350972.stm ⇐an article about mushroom coral eating jellies
https://link.springer.com/article/10.1007/s00338-009-0507-7 ⇐another article about them eating jellies but with more detail

Little Tunny

Domain: Eukarya
Kingdom: Animalia
Phylum: Chordata
Class: Osteichthyes
Order: Perciforms
Family: Scombridae
Genus: Euthynnus
Species: Euthynnus alletteratus

My husband loves to eat tuna. If he could have it every day, I think he would! Little tunny, or little tuna, is a common species of tuna found in the tropical and subtropical waters of the Atlantic Ocean, the Caribbean Sea, the Gulf of Mexico, the Black Sea, and the Mediterranean Sea.

Euthynnus allettatus can grow up to 48 inches and averages around 20 pounds when fully grown. The fish is has countershading, dark-blue gray coloring on top that fades to a silvery-white toward the belly. It has a torpedo-like shape that cuts down on water resistance, similar to species of sharks and dolphins. The base of the tail is thin, and the tail fin is crescent-shaped, allowing the little tuna bursts of speed to evade predators or to catch its prey.

There are two distinct features that help to identify little tunny. On the dark blue-gray top of the fish are a couple of wavy lines that form unique patterns running from the dorsal fin to the tail fin. The second feature is found underneath the small pectoral fins, five to seven small dots that stand out against the silvery-white.

Little tunny are considered opportunistic feeders, which is just a fancy way of saying that this fish will eat almost anything it can get a hold of. Typically, it will feed on crustaceans, smaller fish, and squid.

There is a wide range of organisms that prey on little tunny, including larger tuna, dolphinfish, swordfish, and various species of sharks.

E. allettatus reproduce between April and November around the Atlantic Ocean. Females will release their eggs into the open water for males to fertilize. Females release their eggs multiple times throughout the reproductive months, and the species can produce almost 2 million eggs per year. Whale sharks have been found in these waters, such as off the coast of Isla Mujeres, looking to gorge themselves on fish eggs.

These fish are very important to the local fisheries, including the West Indies. They’re a good fish to consume; the meat is darker and has a stronger taste than larger commercial tuna, and it can be prepared in a number of ways. Little tunny are also good game fish, because they give fishermen a bit of a challenge.

Their population numbers are good, and the species is considered to be of least concern of extinction by the IUCN Red List. If properly regulated, little tunny would be an excellent species of tuna to introduce to larger markets to ease off the pressure of other, scarcer species of tuna.

Isla Mujeres is on my list of places to go. I’ve already decided that while we’re there we’re going to try locally sourced little tunny, if it’s available. I would love to see if my tuna-loving husband enjoys this species of tuna!

Sources and links:
Reef Fish Identification: Florida Caribbean Bahamas 4th Edition by Paul Humann and Ned Deloach
https://www.floridamuseum.ufl.edu/discover-fish/species-profiles/euthynnus-alletteratus/ ⇐more extensive breakdown of little tunny
https://myfwc.com/wildlifehabitats/profiles/saltwater/tuna/little-tunny/ ⇐ key points
http://species-identification.org/species.php?species_group=fnam&menuentry=soorten&id=1925&tab=classificatie
https://www.fishbase.se/summary/97

Bobbit Worm

A bobbit worm (Eunice sp.) emerges from its hole in black sand at night to feed. Photo by Dr. Alex Mustard, more can be found on www.amustard.com

Domain: Eukarya
Kingdom: Animalia
Phylum: Annileda
Class: Polychaeta
Order: Einicida
Family: Einicidae
Genus: Eunice
Species: Eunice aphroditis

Annileda is the phylum of segmented worms, with over 22,000 extant species, including leeches and earthworms. Today, I’m going to share with you the shiny rainbow horror that is the bobbit worm.

Eunice aphroditis looks like a creature from a horror writer’s drug-induced fever dream.

Averaging about 3 feet long and 1 inch wide, the bobbit is also a member of the bristle worms. Along each side of its body are paired, spike-like appendages called parapodia. Each fleshy protrusion contains several bristles. The bobbit worm comes in an array of colors, from black to purple to metallic. The body appears to have this shimmery rainbow effect to it, especially in photographs.

The bobbit worm is an ambush predator. It conceals its body, all 3‒10 feet of it, beneath the sand of the seafloor, except for its antennae. When a fish or crustacean brushes up against the antennae, the bobbit worm emerges from the sand to grab its prey and pull it under.

What make this creature appear nightmarish are its powerful mandibles protruding from its mouth and the speed at which it grabs its prey. The mandibles are scissor-like appendages that extend far from the mouth, and they’re used to grab prey. On occasion, the bobbit worm has been seen cutting its prey in half with the mandibles.

The bobbit worm is found in tropical waters, mostly in the Indian and Pacific Oceans. Not much is known about its reproduction. They are considered rare, and these worms are hard to find because of how they bury themselves beneath the sand.

Eunice aphroditis supposedly gets their common name from the Bobbitt Case in the 1990s involving a married couple with the last name Bobbitt. It’s a disturbing case to read about, so learn about it at your own risk; it involved domestic abuse and violence between the couple.

Despite its nightmarish appearance, the bobbit worm was pretty interesting to look into. There’s still room for research, so if you’re looking for something to focus on, look into polychaetas and the bobbit worm! If you want an idea for a freaky yet colorful horror thriller, I think this worm might give you an idea or two.

Sources and links:
Ocean the Definitive Visual Guide made by the American Natural History Museum
http://www.marinespecies.org/aphia.php?p=taxdetails&id=130053#links
https://eol.org/pages/404312
https://www.ourbreathingplanet.com/bobbit-worm/

Hamelin Cockle

Domain: Eukarya
Kingdom: Animalia
Phylum: Mollusca
Class: Bivalvia
Order: Cardiida
Family: Cardiidae
Genus: Fragum
Species: Fragum erugatum

When I wrote about Shell Beach, Australia, I mentioned the Hamelin cockle, Fragum erugatum. Today, I want to expand on what I wrote.

The Hamelin cockle is a bivalve that belongs to the phylum Mollusca, along with oysters, snails, and squids, to name a few. It’s native to the shallow shores of Western Australia, though it is prevalent in Shark Bay and Shell Beach.

Shark Bay is a hypersaline marine environment. Its seagrass beds restrict tidal movement, and the rate of evaporation is higher than the rate of precipitation, which makes the water really salty. In fact, the water is plankton-deficient because the high salinity makes it hard for plankton to survive.

So what does the cockle do for food? Isn’t it a filter feeder like many of its bivalve brethren?

Hamelin cockles are not strict filter feeders. Instead, they have a partnership with our favorite oceanic BFFs, zooxanthellae. Like coral, the cockle receives leftover food from the zooxanthellae in exchange for protection in well-lit waters. Fragum erugatum will siphon plankton from the water when they can, but it’s never enough to sustain them.

The soft body of the cockle is brown, and the photosynthetic algae live in the soft tissue. The shells are white and appear translucent in the light. Fun fact, zooxanthellae also help to collect calcium carbonate that the cockle uses to make its shell. The entire organism is less than 20 millimeters, which is a little smaller than an inch.

Hamelin cockles are hermaphrodites, meaning they have both male and female sex organs; however, they still need other individuals to reproduce. Between winter and spring, F. erugatum will release their gametes, or eggs, into the water to be fertilized by other Hamelin cockles. The fertilized eggs develop into zooplankton that float around in the water before they settle to the ground and further develop into cockles.

I find these bivalves to be every interesting. They entered Shark Bay over 4000 years ago and really put forth the effort to make the bay and Shell Beach their home. Most living things do not prosper in extreme conditions, especially in areas of high salinity. However, the Hamelin cockle not only adapted to the hypersaline water, but they prospered so beautifully that they left a noticeable mark in the local geology.

Four thousand years’ worth of cockle shells replaced the sandy beach of Shell Beach. Building material was made from the dense accumulation of these shells that, over time, became cemented together. It just blows my mind to think how successful these tiny little organisms are, and that makes them special!

Sources and links:
Ocean the Definitive Visual Guide made by the American Museum of Natural History
https://www.sharkbay.org/publications/fact-sheets-guides/hamelin-cockle/

Tawny Nurse Shark

A group of tawny nurse sharks (Nebris ferrungineus) circling each other at dusk. This behaviour may be related to reproduction, the female, top, looks heavily pregnant in this photo and the male, below, might be able to sense she is soon to give birth. Note in the background there is another group of sharks circling each other. Photo by Alexander Mustard, for more go to www.amustard.com

Domain: Eukarya
Kingdom: Animalia
Phylum: Chordata
Class: Chondrichthyes
Order: Orectolobiformes
Family: Ginglymostomatidae
Genus: Nebrius
Species: Nebrius ferrugineus

I have this kids’ picture book that illustrates 1000 things you can find in the sea, and I use it on occasion to decide what I’m going to research next. I haven’t written about a shark in a while, so I decided to research the Tawny Nurse Shark, also called Nebrius ferrugineus. Though to her friends, she’s referred to as Madame X…

I wish I was kidding about the common name Madame X . Supposedly, the common name was coined in the 1930s by a shark fisherman that found a specimen in Australian waters; before then, it had not been recorded in those areas.

The tawny nurse shark is located in the Indian Ocean, and the in western and southwestern areas of the Pacific Ocean. This shark hangs out near or on the bottom in sheltered areas, including lagoons, channels, seagrass beds, caves on the outskirts of coral reefs, crevices in coral reefs, and right off beaches. They sleep together in secluded areas during the day and hunt for prey at night.

Around the mouth, tawny nurse sharks have barbels—whisker-like appendage—that help them sense prey. They eat small fish and benthic organisms (creatures that live on the seafloor), including crustaceans, sea urchins, and some cephalopods. When it finds potential food, the shark creates a suction to pull the prey out of hiding and into its mouth, where comb-like teeth help to break up hard shells.

This is a pretty docile shark. Divers consider it a favorite because the shark allows the divers to approach it, even touch it. However, when harassed, it will fight back and has been recorded to cause non-fatal bite injuries.

Please do not touch sea creatures unless you have the specific training to do so! You would lash out too if a stranger came up and started putting their hands all over you.

Tawny nurse sharks are considered vulnerable to extinction by the IUCN Red List, and their population numbers are declining. They have a limited home range, so their immediate environment is very important to them. Some populations are declining due to overfishing of the nearby reefs. Some sharks get caught up in gill nets and die as bycatch.

Bycatch refers to any creature that isn’t the target of the catch. So if fisherman are using nets to catch tuna, then anything that isn’t tuna that gets caught up in the net is considered bycatch. Typically, bycatch is thrown back into the ocean, whether it’s alive or dead, because most fishing boats have a bycatch limit.

Tawny nurse sharks are also considered game in some countries. Their “fighting spirit” and strength make them a popular shark to fish for, especially in competitive fishing. Some areas will eat the meat of the tawny nurse shark and ship the fins to Asian countries.

If we’re not careful, this is another species of shark that can disappear before we know it, especially since it has a low reproductive rate. A balance between the fishing industry’s needs and proper fishing regulations must be found in order to address this issue.

Sources and links:
Ocean the Definitive Visual Guide made by the American Museum of Natural History
https://www.floridamuseum.ufl.edu/discover-fish/species-profiles/nebrius-ferrugineus/ ⇐lots of information
https://www.sharks.org/tawny-nurse-shark-nebrius-ferrugineus ⇐brief overview
https://www.fishbase.de/summary/Nebrius-ferrugineus.html
https://fishesofaustralia.net.au/home/species/1974#moreinfo ⇐talks about the Australian populations
https://www.iucnredlist.org/species/41835/10576661

Longnose Butterflyfish

Domain: Eukarya
Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Order: Perciforms
Family: Chaetodontidae
Genus: Forcipiger
Species: Forcipiger longirostris

Butterflyfish, like butterflies, come in all shapes, sizes and colors. Today, I’m going to introduce you to the longnose butterflyfish, or Forcipiger longirotris.

Longnose butterflyfish are distributed throughout the Indo-Pacific Ocean, including around the islands of Oahu and Maui of the Hawaiian island chain. These fish are found on the very edges of seaward reefs, or coral reefs that extend toward the sea.

When you look at the genus name Forcipiger, does anything pop-out at you? Forcip-iger

Forceps are pincer-like instruments made for grasping and holding objects, similar to tweezers. Forceps are typically used in medical and surgical situations.

Forcipiger refers to how the organism feeds, grasping and eating prey whole. The species name longirotris describes the fish’s long snout. F. longirotris feed on small crustaceans found in the rocky crevices of the reef, or they suck them right off of branching coral.

Most individuals of this species are bright yellow with a black head, and a long, thin, silvery-white snout. Rare individuals have been recorded as all black or brown instead of yellow, though this color change has never been recorded in an aquarium. All longnose butterflyfish have a clear caudal (tail) fin, but the rest of their fins are yellow. Near the base of its tail fin is a black spot called an eyespot.

A defense tactic, eyespots are spots on an organism that resemble eyes to confuse predators. Eyespots are typically located away from the head and anything vital. For fish, it’s to fool predators into thinking that the tail end of the fish is the head, especially since the eyes of F. longirotris are hidden in the black coloring of its head. For insects, these eyespots can look like the eyes of other organisms. Eyespots are a common defense found on fish, reptiles, and insects, and each group uses them differently.

Longnose butterfly fish have often been observed in pairs. These fish form monogamous pairs during the breeding season, though it’s unclear if the same two would pair up in the next breeding season. The female releases thousands of eggs into the water column to be carried elsewhere in the water current.

I’ve swum around reefs in the Pacific Ocean twice, once in Hawai’i and once off the Great Barrier Reef. Both times were snorkel only, so I didn’t explore too deep around the reefs, and I doubt I would have seen these fish. I hope to fix that someday because these guys look impressive with their long noses!
There is potential research for Forcipiger longirotris. One, there’s no clear explanation as to why some individuals change their color to all-black or brown and why it’s never done in an aquarium setting. Two, they are labeled as Least Concern by IUCN Red List, but their population numbers haven’t been evaluated since 2009, so there is potential research in re-evaluating their population numbers.

Sources and links:
https://fishesofaustralia.net.au/home/species/425#moreinfo
https://www.waikikiaquarium.org/experience/animal-guide/fishes/butterflyfishes/longnose-butterflyfish/
https://www.fishbase.se/summary/Forcipiger-longirostris.html
https://www.iucnredlist.org/species/165667/6085300

Mola mola

A small sunfish (Mola mola) basks at the surface on a summer’s day. Photo taken by Alex Mustard, find more at www.amustard.com

Domain: Eukarya
Kingdom: Animalia
Phylum: Chordata
Class: Osteichthyses
Order: Tetraodoniformes
Family: Molidae
Genus: Mola
Species: Mola mola

A common rule in evolution is: the strongest, most fit species are the ones to survive. Typically, a species has more than one adaptation that allows it to survive long enough to reproduce. Adaptations can be variations of speed, camouflage, strength, armaments, or some combination of those features..

The Mola mola is the exception to that rule.

The ocean sunfish, Mola mola, is the world’s heaviest bony fish, weighing in at 5,000 pounds. This makes the ocean sunfish 10 times smaller than the whale shark, which is the largest cartilaginous fish.

The Mola mola looks as if some god got bored and stopped after making half a fish. Its large bulbous head looks like it belongs to a fish much bigger than it is, especially with the lack of a caudal (tail) fin. Even looking incomplete, the sunfish is 14 feet from the bottom of its anal fin to the top of its dorsal fin, and it is about 10 feet from head to end.

Mola is the Latin term meaning “millstone,” referencing the creature’s disc-like shape. Humans are not always clever with their naming schemes, though you can count on us being obvious.

Without a functioning caudal fin, the Mola mola awkwardly swims by waggling its dorsal and anal fins. It does not swim very fast, making it easy prey for sharks, killer whales, and sea lions. With their thick, stretchy skin and their typical diet of jellyfish, ocean sunfish may not be a worthy meal for their predators.

Ocean sunfish are also preyed upon by parasites that live in and on their bodies. While an open water fish, they have been spotted near reefs while attempting to remove parasites. Reefs often contain organisms that feed on the parasites found on bigger fish and turtles. Mola molas will also swim flat on the surface of the water to allow birds to pick some of the parasites off.

Jellyfish don’t provide a lot of nutrition, but sunfish eat a lot of them, along with algae, squids, and some crustaceans. Ocean sunfish don’t chew. Instead, they have an infused tooth-plate on the top and bottom parts of its mouth. When they suck jellyfish into their mouths, the action against the plates turns the jellyfish into a gelatinous material that’s easier to consume. Yum!

Ocean sunfish are a slow-moving, easy target for predators to catch. So, how is it still around? How does it populate almost every ocean? A single female Mola mola can release 100 million eggs into the open water each year. Therefore, if 100 females reproduce in a given year, that’s still about 10 billion eggs.

If only those eggs were cash, am I right?

Despite how many eggs they produce, their global populations are on a decline. They get caught in gill nets that trail behind fishing boats; the nets cause them injury and can even suffocate them. Sunfish also fill their stomachs with indigestible plastic bags, which look like jellyfish floating in the water, and the plastic eventually causes them to starve to death.

You can help Mola mola by picking up trash off the beach when you can or when you’re out in public anywhere. Even if you don’t live right next to the water, those discarded plastic bags you see can still make it to the ocean by way of wind. As for the gill nets, try supporting fisherman and fishing companies that have been reported to fish sustainably. Typically, there is a label of some kind on fish products that have been harvested or caught sustainably.

Please do what you can; every little bit helps these goofy-looking fish!

Sources and links:
Reef Fish Identification: Florida Caribbean Bahamas 4th edition by Paul Humann and Ned Deloach
Ocean The Definitive Visual Guide made by the American Museum of Natural History
https://www.montereybayaquarium.org/animals/animals-a-to-z/ocean-sunfish/
https://www.nationalgeographic.com/animals/fish/o/ocean-sunfish/
https://oceansunfish.org/species-and-distribution/ ⇐has more info on sunfish and research relating to them.

Blue Glaucus

Domain: Eukarya
Kingdom: Animalia
Phylum: Mullusca
Class: Gastropoda
Order: Nudibranchia
Family: Glaucidae
Genus: Glaucus
Species: Glaucus atlanticus

The other day, I got a strange text from my dad talking about an article that he found on the Internet describing a blue dragon that had washed up in Texas. He seemed really excited to show me the article because he thought I could blog about it. Well, “blue dragon” didn’t ring any bells, and I thought that it might have been an oarfish, which is dragon-esque. Instead, what I found is a nudibranch, most commonly known as a sea slug.

Glaucus atlanticus goes by many common names: blue glaucus, blue dragon, sea swallow, and blue sea slug, to name a few. No, it does not look like any slug you might have seen or land.

The creature has what looks like a head and a tail. Along its body are three pairs of fan-like appendages that look like wings. The blue sea slug can grow up to 1.2 inches (3cm) in length, which would make it the smallest dragon in the Guinness World Record book. However, it is not the smallest sea slug!

Most sea slugs live on the seafloor. They can live on coral, or the sandy substrate, or even rocky surfaces. Glaucus atlanticus isn’t like its cousins, though. Instead, they are a pelagic sea slug, meaning they live in the open water column. They have been sighted more often up towards the ocean’s surface.

The blue sea slug floats in the water column by storing an air bubble in its body, acting like an air bladder in fish. If it hangs out near the surface, how does it hide from sea birds?

Glaucus atlanticus has a special coloration that allows it to blend into its surroundings called countershading. The blue sea slug floats on its backside, showing the bright blue underbelly toward the sky. The blue helps it blend into the waves and makes it hard for sea birds to see the creature. On the other side, it is a grayish color that blends in with the surface water from below, making it nearly invisible to its underwater predators.

Countershading isn’t the only defense it has against predators. In fact, like most sea slugs, this is a creature you don’t want to touch—no matter how pretty it looks!

One of the things blue dragons consume is the Portuguese man o’ war, a type of hydrozoan known to give nasty stings to beach-goers. The Portuguese man o’ war has long tentacles, almost 30 feet long, which are full of stinging cells.

When the blue dragon consumes the Portuguese man o’ war it stores the hydrozoan’s stinging cells in those fan-like appendages. When a diver or predator gets too close, the blue dragon will brush up against the perceived threat and sting them with the stinging cells. It’s been reported that a sting from a Glaucus atlanticus hurts more than a sting from a Portuguese man o’ war—so watch out for these critters when swimming! They’re found in the warm waters of the Pacific, Indian, and Atlantic Oceans.

If anyone has any suggestions or requests, like this one, let me know! I want to write about what interests you.

Sources and links:
Reef Creature Identification: Florida, Caibbean, Bahamas 3rd edition by Paul Humann, Ned Deloach, and Les Wilk
https://oceana.org/marine-life/corals-and-other-invertebrates/blue-glaucus
https://scubadiverlife.com/marine-species-glaucus-atlanticus/ ⇐has dive-related news articles as well

Lionfish

A lionfish (Pterois volitans) rises up from the reef to hunt silversides. Photo taken by Dr. Alex Mustard, you can find more at www.amustard.com

Domain: Eukarya
Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygi
Order: Scorpaeniformes
Family: Scorpaenidae
Genus: Pterois
Species: Pterois volitans

When talking about invasive species, I mentioned the lionfish. Can they hurt you? Yes. Are they devastating Atlantic coral reefs? Yes. However, they are not evil fish, despite one of their other common names: the devil firefish.

Pterois volitans is a beautiful fish native to the tropical waters of the eastern Indian Ocean and the western Pacific Ocean. They can be found in depths of 7−180ft (2−55m) near seagrass beds, coral reefs, artificial reefs, and sunken ships. I’ve seen them hiding in crevasses or overhanging ledges on the reef.

When diving, lionfish can be fairly easy to identify. Along the head and body of the fish are alternating maroon and white strips, stretching from top to bottom. Long, unique, fan-like fins, with the same stipe pattern, help the lionfish corner its prey against a reef or hard surface. Along the top, are long striped spines that you want to avoid.

Lionfish are carnivorous fish that prey upon shrimp, crabs, and more than 50 species of fish. In their native habitats, they help to keep the reef healthy, and their populations are controlled by the few predators that eat lionfish, including a couple of species of moray eels and the bobbit worm.

In the Atlantic Ocean, however, they can eat all the available prey in a given reef if gone unchecked. With no natural predators in the Atlantic, and the fact that they produce a lot of eggs each year, their populations have boomed while the populations of herbivore and commercial fish have decreased.

Despite their invasion of the Atlantic, lionfish are quite important. Whether it’s in the Pacific, Indian, or Atlantic Ocean, Pterois volitans provides food and income to the coastal communities. Divers pay good money to see lionfish, and the fish is often the target of many spearfishing tournaments in the Atlantic. You can win hundreds of dollars, depending on where you sign up! Because they’re so distinctive, lionfish can be easy targets for divers.

P. volitans are also quite popular in home aquariums around the world. Their unique coloring and flamboyant fins make for a great conversation starter at a party! Just a reminder, though: if you’re getting rid of your aquarium fish, please don’t dump them in the ocean closest to you. Take them to your local aquarium and ask for help. You never want to dump a potential invasive species in your ocean.

Another common name for lionfish is tastyfish. When I was studying in Jamaica, our dive teams would always bring spear guns, and we would hunt lionfish while exploring or doing research. When we’d come back to the lab, we’d clean them and give them to the lab’s cafeteria. Let me tell you, those wonderful ladies made some amazingly spicy lionfish!

If we make it more popular to eat lionfish, then that will help solve the population issues in the Atlantic, and it will help take the pressure off some of our commercial fish. So, the next time you’re at your local fish market or restaurant, ask for lionfish and let the owners know you’re interested!

The coloration of a lionfish is a special adaptation called warning coloration, which indicates to potential predators that it’s unsafe to eat the lionfish. In this case, the warning is legitimate. In the spines along the top are glands that store venom. When the spines puncture the skin the glands release the venom into the wound. The venom can cause excruciating pain, sweating, paralysis, and respiratory distress; rarely has it been fatal to humans.

I had a couple of classmates get stung by lionfish. One kid got stung by a live one they didn’t see in the reef, which is why you never reach your hands into areas you can’t fully see. Another kid got stung when handling a dead lionfish. In both cases, they had to be rushed to the doctor, but even after being treated, the wounds remained quite painful for a while. So please be careful while diving around lionfish or when handling them!

Lionfish (Pterois volitans) fritters offered as an after dive snack. Photo taken by Dr. Alex Mustard, you can find more at http://www.amustard.com

Sources and links:
Ocean: The Definitive Visual Guide by the American Museum of Natural History
https://www.floridamuseum.ufl.edu/discover-fish/species-profiles/pterois-volitans/
https://oceanservice.noaa.gov/facts/lionfish-facts.html
https://www.fisheries.noaa.gov/southeast/ecosystems/impacts-invasive-lionfish
https://www.britannica.com/animal/lionfish
https://blog.nationalgeographic.org/2013/07/19/top-5-myths-about-lionfish/
https://lionfishcentral.org/resources/lionfish-recipes/ ←lionfish recipes you can try at home!