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Creature Feature: Sharks with Unusual Names

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This month we’re talking about some sharks with unusual names. With names that range from the descriptive to the downright strange. Let’s look at three species with weird and wonderful names!

Tasseled Wobbegong

The Tasseled Wobbegong (Eucrossorhinus dasypogon) is a species of carpet shark found in the shallow coral reefs of the Indo-Pacific. This unique shark gets its name from the tassels that hang from its chin and the sides of its head, making it look like it’s wearing a fancy carpet. The scientific name of the Tasseled Wobbegong, Eucrossorhinus dasypogon, comes from the Greek words “eu” meaning good, “krossoi” meaning fringe, “rhinos” meaning nose, and “dasys” meaning hairy, and “pogon” meaning beard, referring to the shark’s characteristic tassels.

The Tasseled Wobbegong has a broad, flattened head and a body that is covered in small, thorn-like projections. These projections, called dermal denticles, are a common feature of shark skin and help to protect the shark from predators and parasites. The Tasseled Wobbegong’s skin is also covered in a unique pattern of dark spots and stripes that allows it to camouflage itself on the reef floor. With their striking appearance and docile nature, they are a favorite of divers and underwater photographers.

Wobbegong Shark © Andy Murch

Despite their wild appearance, Tasseled Wobbegongs are relatively docile and are known to be tolerant of human divers. They are primarily nocturnal, spending most of their days hiding in crevices and under overhangs on the reef. At night, they venture out to hunt small fish and crustaceans, using their powerful jaws to crush their prey.

Although the Tasseled Wobbegong is not considered to be a threatened species, it is facing increasing pressure from habitat degradation and overfishing. In 2018, the International Union for Conservation of Nature (IUCN) listed the Tasseled Wobbegong as a species of “Least Concern” on their Red List, which is a positive sign that the population is currently stable.

SCIENTIFIC NAME: Eucrossorhinus dasypogon

FAMILY: Orectolobidae

MAXIMUM SIZE: 122cm

DIET: Bony fish, crustaceans, and cephalopods

DISTRIBUTION: Found in the waters around southern Australia, including Tasmania and the Bass Strait.

HABITAT: Shallow, coastal waters with rocky or coral reefs, as well as seagrass beds and sandy areas.

CONSERVATION STATUS: 


Crocodile Shark

This unique species (Pseudocarcharias kamoharai) is a small and slender-bodied shark. Which was only disovered in 1985! The genus name, Pseudocarcharias, means “false shark,”. While the species name, kamoharai, honors the Japanese ichthyologist, Kamohara. The English common name “crocodile shark” is derived from its Japanese name mizuwani (水鰐, literally “water crocodile”), which refers to its sharp teeth and habit of snapping vigorously when taken out of the water.

The Crocodile Shark is named for its distinct crocodile-like appearance, with a long snout and sharp teeth. With a maximum length of 1.2 meters. This species is found in deep ocean waters around the globe, from the Atlantic to the Indian Ocean, typically at depths of 200 to 500 meters. However, it has been known to venture as deep as 1,000 meters.

What makes the Crocodile Shark particularly unusual is its opportunistic feeding behavior. This means that it will eat just about anything it comes across. Including small fish, squid, and even other sharks. The Crocodile Shark uses a unique hunting technique to catch its prey. Its slender body and elongated snout allow it to navigate through tight spaces and ambush unsuspecting prey, making it a formidable predator despite its small size.

Since being discovered, we’ve not uncovered much about this elusive species. Not much is known about the biology and behavior of Crocodile Sharks. They are rarely encountered. And in 2019, the Crocodile Shark was listed as “data deficient” on the IUCN Red List. This means that not enough is known about the species to determine its conservation status. This elusive species’ DNA has been analysed and they are determined to be closely related to the Megamouth Shark or sand sharks (Odontaspididae). Alternative research, analysis based on teeth structure, suggests that the closest relatives of the crocodile shark are the thresher sharks.

SCIENTIFIC NAME: Pseudocarcharias kamoharai

FAMILY:  Pseudocarchariidae

MAXIMUM SIZE: 1.2m

DIET: Bony fish and cephalopods

DISTRIBUTION: They are found in tropical and warm temperate waters around the world, including off the coasts of Japan, Australia, South Africa, and Brazil.

HABITAT: Deep offshore waters, typically at depths of 200 to 500 meters, but have been known to come up to shallower depths at night to feed.

CONSERVATION STATUS:


Viper Dogfish

The Viper Dogfish (Trigonognathus kabeyai) is a species of deep-sea shark found in the North Pacific Ocean. This unique shark gets its name from its distinctive appearance, which resembles that of a viper snake, due to the long, fang-like teeth protruding from its jaws. The scientific name comes from the Greek words “trigonos” meaning triangular, “gnathos” meaning jaw, and “kabeya” in honor of the late Japanese ichthyologist, Toshiji Kabeya, who made significant contributions to the study of deep-sea sharks.

The Viper Dogfish is a relatively small species of shark, growing up to just 40 centimeters in length. Its body is slim and elongated, with a dark brown or black coloration that allows it to blend in seamlessly with its deep-sea environment. They’re typically found at depths of between 365 and 1,200 meters, where they feed on a variety of prey including small fish, squid, and crustaceans. Their long, fang-like teeth allow them to easily catch and hold onto their prey, despite their small size.

Despite being a relatively unknown species, the Viper Dogfish has been listed as a species of “Least Concern” on the International Union for Conservation of Nature (IUCN) Red List.

SCIENTIFIC NAME: Trigonognathus kabeyai

FAMILY: Etmopteridae

MAXIMUM SIZE: 40cm

DIET: Small fishes and invertebrates

DISTRIBUTION: Northwest and central Pacific: Japan, Taiwan and Hawaiian Islands.

HABITAT: Deep waters, between 250 – 1000m. Possibly oceanic as some have been caught at 150m over water as deep as 1500m.

CONSERVATION STATUS: 


Banner Image – © Frogfish Photography

Wobbegong – © Andy Murch

Crocodile Shark – © Dianne J. Bray, 2011, Crocodile Shark, Pseudocarcharias kamoharai, in Fishes of Australia, accessed 11 May 2014, http://www.fishesofaustralia.net.au/home/species/3001 | Wikimedia Commons

Viper Dogfish – © Stephen M Kajiura | Wikimedia Commons

The Shark Trust is the leading UK-based shark conservation charity. The team works globally to safeguard the future of sharks, and their close cousins, the skates and rays. Engaging with a global network of scientists, policymakers, conservation professionals, businesses and supporters, to further shark conservation. Established in 1997 to provide a voice for UK sharks, the Shark Trust has an ever-growing number of passionate supporters. And together we're creating positive change for sharks around the world. Want to join us and help protect sharks around the world? Click here! www.sharktrust.org

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Diving with Frogfish in Costa Rica: A Hidden Gem Underwater

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frogfish

In the vast and vibrant underwater world of Costa Rica, there’s a peculiar creature that often goes unnoticed but holds a special place in the hearts of divers: the frogfish. This enigmatic and somewhat odd-looking species is a master of camouflage and a marvel of marine life. Diving with frogfish in Costa Rica is not just a dive; it’s an adventurous treasure hunt that rewards the patient and observant with unforgettable encounters. Let’s dive into the world of frogfish and discover what makes these creatures so fascinating and where you can find them in Costa Rica.

The Mystique of Frogfish

Frogfish belong to the family Antennariidae, a group of marine fish known for their incredible ability to blend into their surroundings. They can be found in a variety of colors, including yellow, pink, red, green, black, and white, and they often have unique spots and textures that mimic the coral and sponges around them. This camouflage isn’t just for show; it’s a critical survival tactic that helps them ambush prey and avoid predators.

One of the most remarkable features of the frogfish is its modified dorsal fin, which has evolved into a luring appendage called an esca. The frogfish uses this esca to mimic prey, such as small fish or crustaceans, enticing unsuspecting victims close enough to be engulfed by its surprisingly large mouth in a fraction of a second. This method of hunting is a fascinating spectacle that few divers forget once witnessed.

Where to Find Frogfish in Costa Rica

Costa Rica’s Pacific coast is dotted with dive sites that offer the chance to encounter these intriguing creatures. Bat Islands (Islas Murciélagos), Catalina Islands (Islas Catalinas), and the area around the Gulf of Papagayo are renowned for their rich marine life, including frogfish. These sites vary in depth and conditions, catering to both novice and experienced divers.

The key to spotting frogfish is to dive with a knowledgeable guide who can point out these master camouflagers hiding in plain sight. They’re often found perched on rocky outcroppings, nestled within coral, or even hiding among debris, perfectly mimicking their surroundings.

frogfish

Diving Tips for Spotting Frogfish

Go Slow: The secret to spotting frogfish is to move slowly and scan carefully. Their camouflage is so effective that they can be right in front of you without being noticed.

Look for Details: Pay attention to the small details. A slightly different texture or an out-of-place color can be the clue you need.

Dive with Local Experts: Local dive guides have an eagle eye for spotting wildlife, including frogfish. Their expertise can significantly increase your chances of an encounter.

Practice Buoyancy Control: Good buoyancy control is essential not just for safety and coral preservation but also for getting a closer look without disturbing these delicate creatures.

Be Patient: Patience is key. Frogfish aren’t known for their speed, and sometimes staying in one spot and observing can yield the best sightings.

Conservation and Respect

While the excitement of spotting a frogfish can be thrilling, it’s crucial to approach all marine life with respect and care. Maintain a safe distance, resist the urge to touch or provoke, and take only photos, leaving behind nothing but bubbles. Remember, the health of the reef and its inhabitants ensures future divers can enjoy these incredible encounters as much as you do.

Join the Adventure

Diving with frogfish in Costa Rica is just one of the many underwater adventures that await in this biodiverse paradise. Whether you’re a seasoned diver or taking your first plunge, the waters here offer an unparalleled experience filled with wonders at every turn. Beyond the thrill of the hunt for frogfish, you’ll be treated to a world teeming with incredible marine life, majestic rays, playful dolphins, and so much more.

So, gear up, dive in, and let the mysteries of Costa Rica’s underwater realm unfold before your eyes. With every dive, you’re not just exploring the ocean; you’re embarking on an adventure that highlights the beauty, complexity, and fragility of our marine ecosystems. And who knows? Your next dive might just be the one where you come face-to-face with the elusive and captivating frogfish. Join us at Rocket Frog Divers for the dive of a lifetime, where the marvels of the ocean are waiting to be discovered.

About the Author: Jonathan Rowe

Are you looking to make a splash online? As a seasoned diver and digital marketer, I specialize in crafting bespoke websites and innovative marketing strategies for dive shops worldwide. With my expertise, your business will not only be seen but also remembered.

From deep-sea to digital depths, I navigate the complex waters of web development and online marketing, ensuring your dive shop stands out in the vast ocean of the internet. Contact Scuba Dive Marketing for more information.

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Marine Life & Conservation Blogs

Creature Feature: Swell Sharks

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In this series, the Shark Trust will be sharing amazing facts about different species of sharks and what you can do to help protect them.

This month we’re taking a look at some truly swell sharks, the Swell Sharks!

Swell Sharks are a group of catsharks belonging to the family Scyliorhinidae. Their most unique feature is probably their threat response: they are able to expand their bodies to twice their normal size by swallowing water! This wedges them into their hiding spot, making it more difficult for predators to bite them from inside.

There are 18 different species of swell shark. In this article, we will focus on two of them, the Swell Shark (Cephaloscyllium ventriosum) and the Australian Swell Shark (Cephaloscyllium laticeps).

The Swell Shark (Cephaloscyllium ventriosum)

Biofluorescence

In 2019, scientists discovered the molecules responsible for a special ability of the swell shark – their biofluorescence. In the dark, special amino acids in their skin reflect the moonlight, appearing bright green in the darkness. This has been found to be species specific, and sex specific, and therefore this unique adaptation may function to help sharks species recognise each other or even potential mates. It may also play a role in camouflage.

Australian Swellshark, Cephaloscyllium laticeps

The Australian Swellshark is also sometimes known as the Draughtboard Shark due to its colouration: It has 11 brown ‘saddles’ that alternate with blotches on its flanks, forming a pattern resembling that of a checkerboard.

Oviparity

Like many other species of Swell Shark, the Australian Swellshark is oviparous. This means that the adult swell shark lays an eggcase with the embryo inside. Depending on the species, the shark may lay two at a time. These eggcases contain a developing embryo and a yolk. Before hatching, the embryo can feed on this yolk for sustenance as it grows. Once fully developed, the embryo hatches out as a fully formed miniature version of the adult shark.

Australian Swell Sharks have a particularly interesting eggcase: cream-coloured and flask shaped, this eggcase has 19-27 transverse ridges (lined horizontally across the eggcase). As with most catsharks, there are long curly tendrils on either end too.

Status

Although the Swell Shark is listed as Least Concern globally on the IUCN Red List of Threatened Species, some species of are listed as Critically Endangered. Take, for instance, the Whitefin Swellshark, endemic to southeastern Australia. Much of its habitat overlaps with areas of intensive fishing effort – as such, although not a target species, they were and still are frequently caught as bycatch. According to the IUCN, populations have reduced by >80% over the past three generations,

Scientific Name: Cephaloscyllium ventriosum

Family: Scyliorhinidae

Maximum Size: 110cm

DietSmall crustaceans, cephalopods and fish

Distribution: Eastern Pacific, most commonly found at 5m to 40m depth.

Habitat: Usually found in rocky areas of kelp beds.

Conservation Status: They’re not typically targeted for food as their meat is generally considered to be of poor quality. They are however, often caught as bycatch in gillnets and trawls.

IUCN Red List Status: Least Concern

For more great shark information and conservation visit the Shark Trust Website


Image Credits:

biofluorescence (Sparks, J. S.; Schelly, R. C.; Smith, W. L.; Davis, M. P.; Tchernov, D.; Pieribone, V. A.; Gruber, D. F., CC BY 4.0 <https://creativecommons.org/licenses/by/4.0>, via Wikimedia Commons)

laticeps (Mark Norman / Museum Victoria, CC BY 3.0 <https://creativecommons.org/licenses/by/3.0>, via Wikimedia Commons)

Eggcase 1 ‘Cephaolscyllium ventriosum’ (vagabondvince310, CC BY 2.0 <https://creativecommons.org/licenses/by/2.0>, via Wikimedia Commons)

Eggcase 2 ‘Cephaloscyllium laticeps eggcase’ (Museum Victoria, CC BY 3.0 <https://creativecommons.org/licenses/by/3.0>, via Wikimedia Commons)

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