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

Alexandrium monilatum

Domain: Eukarya
Kingdom: Prostita
Phylum: Dinophyta
Class: Dinophyceae
Order: Gonyaulacales
Genus: Alexandrium
Species: monilatum

After spending some time talking about the horrors of invasive species, let me throw you a curve ball. We should all agree that invasive/nonnative species are harmful to us and the environments that they infiltrate. However, not all native species are good for their environment either.

How can organisms that are part of the natural balance of their environment be bad for it?

The simplest explanation I can give is this example. Our bodies need potassium to function properly, which we get from food like bananas. If our bodies don’t have enough potassium, then our muscles cramp and we can become stiff and sore. If we consume too much potassium, then it can poison and even kill us. Don’t worry, though; you would have to consume a truck load of bananas in a single day for that to happen.

Like our own bodies, environments need everything in moderation.

Alexandrium monilatum is a single-celled dinoflagellate found in the warm waters of the Atlantic Ocean, Gulf of Mexico, Caribbean Sea, parts of the Pacific Ocean, and the Chesapeake Bay. It is a special kind of bioluminescent algae; when agitated, the organism produces its own light in the form of a soft blue glow.

This dinoflagellate can reproduce sexually and asexually, meaning it can use its own genetic material to make copies of itself without the use of other individuals. It can also produce chains of individuals, ranging from 2 to 80 A. monilatum per strand.

A. monilatum uses photosynthesis to create its own food, making it a phototroph. It is preyed upon by small fish and filter feeders, making it part of the base of the food chain. So how can this armored alga be a bad thing? It sounds so productive, and it even glows blue at night when waves stirs the water!

The problem with A. monilatum is that it is considered a Harmful Algal Bloom (HAB) species. When conditions are right, this species will reproduce faster than it can be consumed by its predators, causing an algal bloom in the water. Blooms are large patches of algae that are seen by the naked eye, meaning there are millions of individuals concentrated in a single area.

Blooms are considered a problem because the water contains a finite amount of nutrients available to the algae. Once the supply runs out, it’ll take time to replace those needed nutrients. So these blooms are extremely productive for a short time, before the algae run out of food and die. When they die, they start to decompose. The process of decomposition takes up a lot of oxygen, and without the photosynthesizers there to replace the oxygen being used, the water becomes hypoxic—or worse, anoxic.

Once the amount of dissolved oxygen in the water is depleted, the area becomes a dead zone, and all the fish and other marine organisms either leave or suffocate in the water. Dead zones aren’t always permanent; however, they are still an inconvenience to the marine life and to us and should be prevented at all cost.

It is not my purpose to make Alexandrium monilatum out to be a bad guy, just to show that even native species can harm their environment under certain conditions. Algal blooms, or red tides, can be caused by a steep increase in important nutrients found in fertilizers, which enter the water as run-off from nearby farms, gardens, and agricultural facilities. A boom in available food causes a boom in creatures that depend on it, and that’s true no matter the species.

Bioluminescent algae are fascinating. I was lucky enough to swim at night in a lake full of a species of bioluminescent algae, though I’m uncertain what species it was. It was a magical experience that I will never forget, so I was excited to talk about A. monilatum and to discuss the importance of balance within an ecosystem.

Sources and more info:
https://naturalhistory2.si.edu/smsfp/IRLSpec/Alexan_monila.htm
https://www.chesapeakebay.net/discover/field-guide/entry/alexandrium_monilatum
https://www.vims.edu/bayinfo/habs/guide/alexandrium.php
https://www.vdh.virginia.gov/environmental-epidemiology/harmful-algal-blooms-habs/alexandrium-monilatum-hab-in-lower-york-lower-james-rivers-and-chesapeake-bay/frequently-asked-questions-faqs-alexandrium-monilatum/

Caribbean Spiny Lobster

A Caribbean spiny lobster (Panulirus argus) emerges onto a coral reef in late afternoon. Photo taken by Dr. Alexander Mustard. More photos like this can be found on his website: www.amustard.com

Domain: Eukarya
Kingdom: Animalia
Phylum: Arthropoda
Class: Malacostraca
Order: Decapoda
Family: Palinuridae
Genus: Panulirus
Species: Panulirus argus

Originally, I was going to write a post about the Spiny Lobster, but then I realized that there are at least two species with that common name. One lives in the Atlantic and the other in the Pacific. Today, I’ll be talking about the Caribbean spiny lobster, or Panulirus argus.

P. argus can be found around coral reefs, seagrass beds, and rocky areas off the coast from North Carolina to Brazil, in the Gulf of Mexico, and the Caribbean Sea.

These guys are a combination of tan, black, and white, with large white spots across their spiny bodies. They also have two long antennae and large, forward-facing eyes.

Unlike other lobsters, the Caribbean spiny lobster’s claws are not terribly large and don’t cause a lot of damage. However, these guys are not without their defenses. The carapace—the body of the lobster and not the tail—is covered with small spikes and can cause injury to anyone who tries to pick up these guys barehanded. So, swimmers, don’t touch them!

These guys start out rather tiny as larvae. In fact, they’re considered zooplankton and are food for numerous fish. If a larvae survives, it eventually can grow to about 2 ft. long, though not without getting rid of its old exoskeletons a few times all the way.

P. argus are considered to be omnivores, though they primarily feed on bivalves and gastropods, and they have been seen eating other things as well.

I think the coolest thing about these guys is their mass migrations. In autumn, P. argus will be seen walking in long, single-file lines to deeper waters during the day; in theory, to find cooler areas and more food.

I’ve seen Caribbean spiny lobsters most often at fresh fish markets, though I’ve seen them a few times during some of my dives. They’re really important to coastal economics, because a lot of coastal areas will hunt them and export their sought-after meat to other countries.

Unfortunately, this means that this species can become victim of overfishing, and population numbers can be wiped out completely. There is no conclusive data on the status of their populations as a whole and whether or not the species may become threatened by extinction, but that doesn’t mean we shouldn’t be careful.

If regulations aren’t put into place, then entire populations can be wiped out, and many small countries that rely on their export will suddenly be faced with an economic crisis.

Sources:
Reef Creature Identification: Florida, Caribbean, Bahamas 3rd edition by Paul Humann, Ned DeLoach, and Les Wilk
https://animaldiversity.org/accounts/Panulirus_argus/
https://marinebio.org/species/caribbean-spiny-lobsters/panulirus-argus/
https://www.fisheries.noaa.gov/species/caribbean-spiny-lobster
https://thisfish.info/fishery/species/caribbean-spiny-lobster/
https://oceana.org/marine-life/cephalopods-crustaceans-other-shellfish/caribbean-spiny-lobster

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

Flamingo Tongue

A flamingo tongue (Cyphoma gibbosm) feeding on a seafan (Gorgonia ventalina). Cyphomas feed on corals and concentrate the toxic chemicals into their mantle, which they then wrap around the outside of its white shell. The mantle is brightly coloured to warn predators of its toxicity. The mantle also absorbs oxygen from the water. Photo and caption by Dr. Alex Mustard. Find more photos at www.amustard.com

Domain: Eukarya
Kingdom: Animalia
Phylum: Mollusca
Class: Gastropoda
Order: Littorinimorpha
Family: Ovulidae
Genus: Cyphoma
Species: Cyphoma gibbosum

Please note: no flamingos were harmed in the making of this creature.

Honestly, I don’t know how they got they got their common name. These mollusks look nothing like flamingo tongues, and I should know because I’ve been staring at flamingo pictures for the past several minutes!

Cyphoma gibbosum are interesting mollusks to find on a reef. They have bright orange spots that are outlined in black on a creamy background, but the mollusks aren’t terribly big, averaging about 1‒1.5 inches long. When they’re young, they don’t have many rectangular spots, but as they get older, the spots get smaller and more numerous.

Flamingo tongues can be found on coral reefs in the Western Atlantic, from North Carolina to Brazil, in the Gulf of Mexico, and in the Caribbean Sea. They make their homes on gorgonian corals (soft corals), which is the only thing they consume—eating the soft tissue of the coral they sit on. Flamingo tongues use the chemicals from their prey in their own natural defense against predators by storing the chemicals in their soft tissue, the mantle, making them taste disgusting to most fish. Their predators include pufferfish, hogfish, and the Caribbean spiny lobster.

For those who don’t know—which until recently included myself—the bright spots that you see aren’t part of their shell. In fact, their shell is a very basic-looking cream color, and the spots that you’ll see when diving and snorkeling at a reef are actually the fleshy bits that hide the shell, called the mantle. When frightened, a C. gibbosum will retract into its creamy shell, pulling its colorful patterned mantle inside.

Unfortunately, the populations of C. gibbosum have decreased rapidly in recent years due to the increase activity of humans. Specifically, divers and snorkelers see these cool guys on the reef and think that the spots are part of their shell, so they decide to bring them back as a neat souvenir. When the creature dies, all that’s left is a simple shell sans the color and the spots.

Flamingo tongue shells have also boomed in popularity in the coastal jewelry business, so people will collect a lot of them to make their jewelry. As far as I’m aware, there is no data that can determine if the species is threatened or endangered and there are no regulations in place to protect them. However, that still shouldn’t stop us from being more aware of the situation and doing what we can to help, for instance know where the shells on your jewelry come from before you buy it.

I was lucky enough to spot a few of these guys while diving in Jamaica. I saw them the most when we went to a gorgonian-heavy reef, naturally, and the C. gibbosum were one of the cooler things to spot while swimming by. They’re small and can be easy to miss, but whenever I found one, I was mesmerized by it for a few beats before moving on. I think the coolest thing about them is their ability to be unaffected by the toxins the soft coral produce to deter predators, and they can use it to make themselves distasteful too.

Sources:
Ocean: The Definitive Visual Guide made by the American Museum of Natural History
Reef Creatures Identification: Florida, Caribbean, Bahamas 3rd Ed. By Paul Humann, Ned DeLoach, and Les Wilk
http://www.marinespecies.org/aphia.php?p=taxdetails&id=432297#links
http://species-identification.org/species.php?species_group=caribbean_diving_guide&id=410
http://www.thecephalopodpage.org/MarineInvertebrateZoology/Cyphomagibbosum1.html
https://oceana.org/marine-life/cephalopods-crustaceans-other-shellfish/flamingo-tongue
https://www.lamar.edu/arts-sciences/biology/marine-critters/marine-critters-1/flamingo-tongue.html