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

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.

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!

Doctorfish

Domain: Eukarya
Kingdom: Animalia
Phylum: Chordata
Class: Osteichthyes
Order: Perciformes
Family: Acanthuridae
Genus: Acanthurus
Species: Acanthurus chirurgus

Last time on Doctor Who, the Doctor was mortally wounded and forced to regenerate…again. This time, though, to everyone’s surprise and horror, the Doctor turned into a fish. And not just any fish, but the tropical surgeonfish known as the Doctorfish—bum bum buuuuuuuuuuuum!

For those of you who don’t know, I’m a giant nerd, and I laughed way too hard when I realized that I could combine Acanthurus chirurgus with Doctor Who. I have no shame—most of the time.

Anyways, the Doctorfish is a type of surgeon fish that inhabits coral reef areas and can be commonly found in Florida, Bahamas, and the Caribbean. They can also be found in the waters of the Gulf of Mexico, north to Massachusetts, south to Brazil, your neighbors’ exotic aquarium, and the tropical waters of West Africa.

Color is not always an easy way to identify these Doctorfish because they can range from bluish gray to dark brown, and they can pale or darken dramatically between individuals. The major way to identify them while diving is by looking at the body; all doctorfish have 10‒12 vertical bars between their head and their tail. They also have distinct markings around their eyes, almost like flashy eye make-up.

Acanthurus chirurgus are herbivores that feed on algae, and they even have special teeth that allow them to pick off the algae growing in the sand, in rocky areas, and even on coral. In fact, these guys are really important to reef health because they can consume the algae that grow on coral, which would otherwise smoother the coral and their best friends, the zooxanthellae.

The origin of their common name is pretty cool. A. chirurgus have spines on either side of their caudal peduncle, or the base of their tail, that were discovered to be really sharp like a scalpel that doctors use. When feeling defensive, surgeonfish will use those spines as weapons by slashing their tails side to side at their aggressors.

Typically, Doctorfish will keep their distance from divers and will try to stay away if approached. However, people handling these fish can get serious injuries which are often quite painful and can lead to serious infection, especially since there is a crazy amount of bacteria and viruses in a single drop of water! So please be careful when diving with or handling doctorfish!

They are a common fish species found in private aquariums, and while they are not considered to be at risk of becoming endangered, you should still be aware of how they are caught and sold before purchasing individuals for your aquarium.

The doctorfish was one of the fish species I had to learn to identify for my Coral Reef Ecology class in college. I’ve seen them a handful of times when diving around reefs, and I’ve even watched them eating the algae from the coral, which was pretty cool to witness. I’ve read that you can eat Doctorfish, but I won’t try that because of the slight chance of getting ciguatera poisoning—which I’ll save for another ramble!

Sources and cool links:
Reef Fish Identification: Florida Caribbean Bahamas 4th ed. By Paul Humann and Ned DeLoach
http://species-identification.org/species.php?species_group=caribbean_diving_guide&menuentry=soorten&id=209&tab=beschrijving
https://www.floridamuseum.ufl.edu/discover-fish/species-profiles/acanthurus-chirurgus/
https://www.iucnredlist.org/species/177982/1510626
https://www.fishbase.de/summary/943

Yellowtail Damselfish

Adult male yellowtail damselfish, photo taken by Dr. Alex Mustard. Please check out his website www.amustard.com for more

Yellowtail Damselfish
Domain: Eukarya
Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Family: Pomacentridae
Order: Perciformes
Genus: Microspathodon
Species: Chrysurus

I realized that I have yet to talk about fish, and because there are so many of them, I decided that it’s high time to start. I’m not sure why I wanted to kick it off with the Yellowtail Damselfish. I was going through a fish ID book I own, and it was the first one to catch my attention, maybe because I was already familiar with it. They are pretty neat looking fish and I want to share some interesting facts about them!

There are a lot of fish that are born looking completely different than their adult selves. Seriously, some fish can go through some intense changes before they settle into themselves as adults, but even then it might not be completely decided—I’m looking at you, clown fish! Yellowtail Damselfish are one of those species that look almost like a completely different fish at every stage of their life.

When they’re juveniles, they have these dark blue, almost black bodies that are littered in bright blue dots, with clear tail. Then in their intermediate stage, like high-school for humans, their dots shrink and their tail becomes a bright yellow. As adults, they lose the blue dots, but keep the dark color with the bright yellow tail.

Intermediate phase of the yellowtail damselfish, taken by Dr. Alex Mustard. Please visit his website, www.amustard.com for more!

Yellowtail Damsel can be found in the warm waters of Florida, the Bahamas, and the Caribbean. They live on the tops of coral reefs where they eat algae and the polyps of fire coral. The juveniles tend to stick close to the branches of the fire coral where they hide from predators and loud divers.

The Yellowtail Damselfish was one of the species I had to learn how to identify for a course I took in college. Its tail is a pretty clear giveaway for the species, at least from the list I had to identify. It was especially easy for me to recognize the juvenile stage. However, the individual I had to identify was completely yellow with flecks of blue, which is a temporary change they can accomplish. Anyways, I found the younger stages to be beautiful and a joy to spot on the reefs!

Sources:
Reef Fish Identification: Florida, Caribbean, Bahamas 2nd edition by Paul Humann and Ned Deloach
https://www.fishbase.se/summary/Microspathodon-chrysurus