Connect with us
background

Marine Life & Conservation Blogs

Creature Feature: Blue Shark

Published

on

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 take a journey into the life of the most migratory shark on earth. The Blue Shark.

The name says it all. Blue sharks have a striking metallic blue back, with a white underside. This is a classic example of counter shading. A type of camouflage used by many sharks. This means they’re concealed both from above (as their back matches the blue of the ocean) and below (the white looks similar to the light coming in at the surface).

Their scientific name also describes them very well. The first part of their scientific name (Prionace) is derived from Greek – with ‘prion’ meaning ‘saw’ and ‘akis’ meaning ‘pointed’. This refers to their sharp and serrated triangular teeth. Which are used for gripping hold of slippery prey, such as fish and squid. While the second part (glauca) is Latin for ‘blueish grey’.

The most migratory of all sharks. Blue sharks undertake huge yearly migrations – totalling over 9000km (5700+ miles)! Check out the 60 Second Sharks below to find out all about it.

They are also the most heavily fished shark on the planet. The Blue shark is caught and consumed for meat across the globe. It may be surprising then, to see that they are globally ‘Near Threatened’ on the IUCN Red List of Threatened Species. This is, in part, because Blue Sharks give birth to litters of 4-135 pups (average 35).

This is a relatively large number of pups for a shark. This means that Blue sharks are more resilient than some species to destructive fishing. However, the species is critically endangered in the Mediterranean. If fishing pressures continue, the species is likely to shift into one of the threatened categories globally. Even with larger litters, the populations are unlikely to cope with how many sharks are currently being captured.

Blue sharks are known for being highly inquisitive and curious. When snorkelling or diving near them, they will often come close to investigate people. They come together in groups to feed. Preying on shoals of fish or carrion (i.e., carcasses). They’re most active in the early morning and night. When they cruise slowly on the surface.

SCIENTIFIC NAME: Prionace glauca

FAMILY:  Carcharhinidae

MAXIMUM SIZE: 3.8m

DIET: Opportunistic feeders. Diet predominately small fishes and squid, but will also eat cuttlefish, lobster, shrimp, carrion and sea birds.

DISTRIBUTION: All temperate and tropical waters. In tropical waters they’re found much deeper, where it’s cooler.

HABITAT: Often found in the open ocean from the surface to depths of 600m. Prefers temperatures of 12-20°C but can tolerate 8–30°C.

CONSERVATION STATUS

Banner Image – ©Peter de Maagt

Images – ©Frogfish Photography


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.

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

Blogs

The Ocean Cleanup Breaks 10,000,000 KG Barrier

Published

on

ocean cleanup

The Ocean Cleanup, the global non-profit project, has removed a verified all-time total of ten million kilograms (22 million lbs.) of trash from oceans and rivers around the world – approximately the same weight as the Eiffel Tower.

To complete its mission of ridding the oceans of plastic, The Ocean Cleanup uses a dual strategy: cleaning up the Great Pacific Garbage Patch (GPGP) to remove the plastic already afloat in the oceans, while stopping the flow of plastic from the world’s most polluting rivers.

Through cleaning operations in the GPGP and in rivers in eight countries, the cumulative total of trash removed has now surpassed ten million kilograms. This milestone demonstrates the acceleration of The Ocean Cleanup’s impact, while underlining the astonishing scale of the plastic pollution problem and the need for continued support and action.

While encouraging for the mission, this milestone is only a staging point: millions more tons of plastic still pollute our oceans and The Ocean Cleanup intends to continue learning, improving and innovating to solve this global catastrophe.

This announcement comes as governments from around the world meet to continue negotiations to develop a new legally binding instrument to end plastic pollution at INC4 in Ottawa, Canada. Representatives of The Ocean Cleanup will be in attendance and the organization will be urging decision-makers to collaborate towards a comprehensive and ambitious global treaty which addresses plastic at all stages of its life cycle and in all marine environments worldwide, including in areas beyond national jurisdiction.

It is encouraging to see that the need for remediation is reflected in the various options for potential treaty provisions. It is essential that the final treaty contains clear targets for the remediation of legacy plastic pollution, and reduction of riverine plastic emissions.

Tackling plastic pollution requires innovative and impactful solutions. The treaty should therefore incentivize the innovation ecosystem by fostering innovations that make maximal use of data, technology and scientific knowledge – such as those designed and deployed by The Ocean Cleanup.

‘After many tough years of trial and error, it’s amazing to see our work is starting to pay off – and I am proud of the team who has brought us to this point.’ said Boyan Slat, Founder and CEO of The Ocean Cleanup. ‘While we still have a long way to go, our recent successes fill us with renewed confidence that the oceans can be cleaned.’

The Ocean Cleanup was founded in 2013 and captured its first plastic in 2019, with the first confirmed catch in the GPGP coming soon after the deployment of Interceptor 001 in Jakarta, Indonesia. After surpassing one million kilograms of trash removed in early 2022, the non-profit project has since progressed to the third iteration of its GPGP cleaning solution, known as System 03, and a network of Interceptors currently covering rivers in eight countries, with more deployments set for 2024.

About The Ocean Cleanup

The Ocean Cleanup is an international non-profit organization that develops and scales technologies to rid the world’s oceans of plastic. They aim to achieve this goal through a dual strategy: stemming the inflow via rivers and cleaning up the legacy plastic that has already accumulated in the ocean. For the latter, The Ocean Cleanup develops large-scale systems to efficiently concentrate the plastic for periodic removal. This plastic is tracked and traced through DNV’s chain of custody model to certify claims of origin when recycling it into new products. To curb the tide via rivers, The Ocean Cleanup has developed Interceptor™ solutions to halt and extract riverine plastic before it reaches the ocean. Founded in 2013 by Boyan Slat, The Ocean Cleanup now employs a broadly multi-disciplined team of approximately 140. The foundation is headquartered in Rotterdam, the Netherlands.

For more information, visit: theoceancleanup.com and follow @theoceancleanup on social media.

Continue Reading

Marine Life & Conservation Blogs

Creature Feature: Dusky Shark

Published

on

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 the Dusky Shark, a highly migratory species with a particularly slow growth rate and late age at maturity.

Dusky sharks are one of the largest species within the Carcharhinus genus, generally measuring 3 metres total length but able to reach up to 4.2 metres. They are grey to grey-brown on their dorsal side and their fins usually have dusky margins, with the darkest tips on the caudal fin.

Dusky Sharks can often be confused with other species of the Carcharhinus genus, particularly the Galapagos Shark (Carcharhinus galapagensis). They have very similar external morphology, so it can be easier to ID to species level by taking location into account as the two species occupy very different ecological niches – Galapagos Sharks prefer offshore seamounts and islets, whilst duskies prefer continental margins.

Hybridisation:

A 2019 study found that Dusky Sharks are hybridising with Galapagos Sharks on the Eastern Tropical Pacific (Pazmiño et al., 2019). Hybridisation is when an animal breeds with an individual of another species to produce offspring (a hybrid). Hybrids are often infertile, but this study found that the hybrids were able to produce second generation hybrids!

Long distance swimmers:

Dusky sharks are highly mobile species, undertaking long migrations to stay in warm waters throughout the winter. In the Northern Hemisphere, they head towards the poles in the summer and return southwards towards the equator in winter. The longest distance recorded was 2000 nautical miles!

Very slow to mature and reproduce:

The Dusky Shark are both targeted and caught as bycatch globally. We already know that elasmobranchs are inherently slow reproducers which means that they are heavily impacted by overfishing; it takes them so long to recover that they cannot keep up with the rate at which they are being fished. Dusky Sharks are particularly slow to reproduce – females are only ready to start breeding at roughly 20 years old, their gestation periods can last up to 22 months, and they only give birth every two to three years. This makes duskies one of the most vulnerable of all shark species.

The Dusky Shark is now listed on Appendix II of the Convention on the Conservation of Migratory Species (CMS), but further action is required to protect this important species.

Scientific Name: Carcharhinus obscurus

Family: Carcharhinidae

Maximum Size: 420cm (Total Length)

Diet: Bony fishes, cephalopods, can also eat crustaceans, and small sharks, skates and rays

Distribution: Patchy distribution in tropical and warm temperate seas; Atlantic, Indo-Pacific and Mediterranean.

Habitat: Ranges from inshore waters out to the edge of the continental shelf.

Conservation status: Endangered.

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


Images: Andy Murch

Diana A. Pazmiño, Lynne van Herderden, Colin A. Simpfendorfer, Claudia Junge, Stephen C. Donnellan, E. Mauricio Hoyos-Padilla, Clinton A.J. Duffy, Charlie Huveneers, Bronwyn M. Gillanders, Paul A. Butcher, Gregory E. Maes. (2019). Introgressive hybridisation between two widespread sharks in the east Pacific region, Molecular Phylogenetics and Evolution 136(119-127), https://doi.org/10.1016/j.ympev.2019.04.013.

Continue Reading

E-Newsletter Sign up!

Experience the Red Sea in May with Bella Eriny Liveaboard! As the weather warms up, there’s no better time to dive into the crystal clear waters of the Red Sea. Join us on Bella Eriny, your premier choice for Red Sea liveaboards, this May for an unforgettable underwater adventure. Explore vibrant marine life and stunning coral reefs Enjoy comfortable accommodation in our spacious cabins Savor delicious meals prepared by our onboard chef Benefit from the expertise of our professional dive guides Visit our website for more information and to secure your spot: www.scubatravel.com/BellaEriny or call 01483 411590 More Less

Instagram Feed

Popular