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Marine Life & Conservation Blogs

Creature Feature: The Houndsharks

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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 a few of the species from the houndshark family. The houndsharks, a.k.a. Triakidae, are a family of around 45 species. In this Creature Feature we’ll be looking at the Leopard Shark and Common Smoothhound.

Houndsharks are known for having two large, spineless dorsal fins, an anal fin and oval-shaped eyes with nictating eyelids. Animals with nictating eyelids have a third, clear, eyelid. This protects the eye whilst still allowing the houndsharks to be able to see. Houndsharks are small to medium in size, with adults ranging from around 37cm to 220cm. They’re one of the largest families of sharks. They are distributed throughout the world in warm and temperate waters. They predominantly feed on fish and invertebrates on the seafloor and in midwater.

Leopard Shark

Confusingly named after a feline species, the Leopard Shark does indeed belong to the houndshark family. Its name comes from the unique saddle marks and spots that cover the species, resembling those of a leopard (as seen in the banner image).

It is one of the most common sharks found along the Pacific coast of North America. They are active, strong-swimming sharks. Sometimes spotted resting on sand among rocks. Leopard Sharks form large, nomadic schools with different species (such as the North Pacific Spiny Dogfish and Bat Rays.

The species is classified as Least Concern on the IUCN Red List of Threatened Species. Leopard Sharks are primarily caught by recreational anglers. But they are also taken as incidental catch in commercial fisheries. They are generally well managed by commercial fisheries. They are also popular in aquariums due to their distinctive markings and hardiness. The poaching of pups for the aquarium trade has been a significant problem.

SCIENTIFIC NAME: Triakis semifasciata

FAMILY: Triakidae (Houndsharks)

MAXIMUM SIZE: 180cm

DIET: Small sharks eat crabs, the siphons off clams and worms from the seafloor. Large sharks may eat fishes and even other smaller sharks.

DISTRIBUTION: Northeast Pacific – west coast of the United States from southern Washington to the Gulf of California (Mexico).

HABITAT:  Cool to warm waters. Most common on or near the seabed in bays and estuaries. Females give birth in water less than 1m deep.

CONSERVATION STATUS:

Common Smoothhound

A medium-sized, unspotted houndshark. The Common Smoothhound is often confused with the Starry Smoothhound which usually has white spots along its back. It’s also often confused with the Tope Shark. Smoothounds are so called because they will gather in large numbers, like a pack of dogs.

The Common Smoothhound is classified as globally Endangered on the IUCN Red List of Threatened Species. The species is classed as Vulnerable in Europe. It is targeted by fisheries across its range, both for sport and in commercial fisheries. The species is caught for food across the Mediterranean, European and West African fisheries.  There is often confusion between the Common Smoothhound and Starry Smoothhound. Starry Smoothounds often doesn’t have any stars/spots. So they are very similar in appearance. Genetic analysis is the most reliable way to distinguish smoothhounds.

SCIENTIFIC NAME:  Mustelus mustelus

FAMILY: Triakidae (Houndsharks)

MAXIMUM SIZE:  175cm

DIET:  Mainly crustaceans. Also cephalopods and bony fishes.

DISTRIBUTION:  Temperate east Atlantic. UK to the Mediterranean, Morocco down to South Africa and the Indian Ocean coast.

HABITAT:  Continental shelves and upper slopes. Usually 5-50m, but occasionally down to at least 800m.

CONSERVATION STATUS:


For more amazing facts about sharks and what you can do to help the Shark Trust protect them visit the Shark Trust website by clicking here.

Banner Image – ©Barbar Ash via Shutterstock

Image of Leopard Shark – ©ScubaZoo

Maps – ©Chris_huh, via Wikimedia Commons

Smoothound Illustration – ©Marc Dando

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

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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The Thrilling Encounter with Tiger Sharks at Beqa Lagoon’s ‘The Colosseum’ with Coral Coast Divers

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tiger sharks

Nestled in the heart of Fiji, Beqa Lagoon is not just another dive destination; it’s a world-renowned haven for shark enthusiasts. Often hailed as the shark diving capital of the world, this magnificent lagoon offers an unparalleled underwater adventure. Let’s delve into the depths of Beqa Lagoon to understand what makes it a pinnacle of shark diving.

The History Of Shark Diving In The Beqa Lagoon

This journey began decades ago, evolving from the initial fascination and respect the local Fijian communities had for these magnificent creatures. In the early stages, shark diving in the lagoon was a rare and awe-inspiring experience, primarily pursued by adventurous divers seeking close encounters with these misunderstood predators. Dive centers began working with local communities and fishermen by protecting the area from fishing, and also shark baiting to encourage sharks to attend the dive sites. This had a profound effect not only on the shark population but on the local reefs and other fish populations as well. The local reefs are now much healthier than they were in the early 2000’s, there is a much greater population of other marine life, and the shark diving is world class! Over the years, as knowledge and appreciation of this area for sharks grew, Beqa Lagoon emerged as a premier destination for shark enthusiasts worldwide. This transformation was fueled by the collaborative efforts of local dive operators, conservationists, and the local Fijian people, who worked together to develop sustainable shark diving practices and by protecting large areas from fishing. These efforts not only positioned Beqa Lagoon as a global hotspot for shark diving but also played a pivotal role in shark conservation and research. Today, the legacy of shark diving in Fiji continues, offering a window into the fascinating world of these apex predators and a testament to the power of sustainable tourism in marine conservation.

tiger sharks

What Makes The Beqa Lagoon So Great For Shark Diving

Beqa Lagoon’s geographical features make it an exceptional location for shark diving. Encircled by one of Fiji’s most extensive barrier reefs, this natural fortress creates a serene and protected sanctuary, ideal for the flourishing marine life within. The barrier reef not only acts as a buffer against strong ocean currents but also nurtures a vibrant underwater ecosystem, providing a haven for a wide array of marine species, including sharks. Just outside the lagoon, the ocean floor descends into deep drop-offs, creating an environment where pelagic species can live and explore. This unique topography allows divers to experience both the colorful, shallow coral gardens and the thrilling depths where larger sharks roam. The healthy state of the reefs and surrounding oceans in the area is a crucial factor in sustaining a diverse marine population. This blend of a protected lagoon with the proximity to the deep ocean makes Beqa Lagoon not just a safe and accessible diving location but also a dynamic and exhilarating shark diving hotspot. This deep water surrounding the Beqa Lagoon is where the beautiful tiger sharks reside.

Why “The Colosseum” Has The Highest Rate Of Tiger Shark Encounters

The dive site called “The Colosseum”, which is a marine sanctuary operated in an agreement between the dive center Coral Coast Divers and the local Fijian community of Yanuca Island, is the dive site where Tiger Sharks are most commonly seen. This dive site is located on a reef which is very close to the outer edge of the Lagoon. So, while it may take an extra 20 minutes or so travel time via boat to reach this dive site, the increased likelihood of witnessing Tiger Sharks makes it all worthwhile. The Tiger Sharks in the area generally roam the deeper waters just outside of the lagoon. Once the bait is lowered into the water on the first dive, the scent begins traveling. The Tiger sharks pick it up and generally meet the divers on the second dive of the trip for an incredible shark feeding experience!

The Shark Diving Experience at Beqa Lagoon:

Diving in Beqa Lagoon is an immersive experience. The clear, warm waters offer excellent visibility, allowing divers to witness the majestic beauty of sharks in their natural habitat. From the awe-inspiring Tiger Sharks at ‘The Colosseum’ to the formidable Bull Sharks, the lagoon is a stage for some of the most thrilling underwater performances.

The Diversity of Shark Species: Up to 8 Species Of Sharks On 1 Dive

What truly sets Beqa Lagoon apart is the diversity of shark species. In addition to Tiger and Bull Sharks, divers can encounter up to eight different species in a single dive, including Lemon Sharks, Nurse Sharks, and potentially even the rare Silver Tip Sharks. This diversity is a testament to the health and richness of the marine ecosystem in Beqa Lagoon.

tiger sharks

A Shark Diving Capital Of The World

Beqa Lagoon stands unrivaled as the shark diving capital of the world, not just for the thrill of the dive but for the holistic experience it offers. It’s a place where nature, conservation, and culture converge to create an unforgettable diving adventure.

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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