Jun 7

Atlantic bluefin tuna (Thunnus thynnus)

Species: Atlantic bluefin tuna (Thunnus thynnus)

Status: Endangered (EN)

Interesting Fact: The Atlantic bluefin tuna can swim at speeds of up to 72 kilometres per hour when pursuing its prey.

More information: The enormous Atlantic bluefin tuna can grow to lengths of 4.6 metres and weigh up to 684 kilograms. This fish species has two types of muscle, one for continuous long-distance swimming and the other for short, fast bursts of speed. This amazing adaptation means that individuals of this species are able to swim across the Atlantic Ocean in just 60 days. Although the Atlantic bluefin tuna is generally found swimming in mixed species schools close to the surface of the water, it is capable of diving to depths of up to 1,000 metres when chasing prey. Another fascinating adaptation of the Thunnus genus is the blood exchange system known as the rete mirable which enables individuals to swim in water that is much to cold for other fish. The Atlantic bluefin tuna is a highly migratory species and has a naturally occurring magnetic mineral located in its head that helps with navigation to and from its spawning grounds.

The severe exploitation of the Atlantic bluefin tuna has led to the drastic decline of every known population, particularly in the North Atlantic Ocean. Despite quotas being in place to ensure sustainable numbers are removed from the population, the limits are frequently not respected and unless the legal levels are suitably enforced, it is predicted that some Atlantic bluefin tuna stocks will collapse. The western Atlantic stock may have already collapsed and is now in grave danger of extinction due to overfishing. In the Mediterranean, tuna ranching poses the greatest threat to this species. Individuals are captured alive and taken to a ranch where they are fattened before being sold. Since 1998, catch limits have been in place and in 2006 the International Commission for the Conservation of Atlantic Tunas (ICCAT) established a 15 year recovery plan for the Atlantic bluefin tuna. The plan includes stricter catch limits and closing certain fisheries at specific times of the year to allow the local stocks to recover.

Find out more about Atlantic tuna conservation: International Commission for the Conservation of Atlantic Tunas (ICCAT).

See images and videos of the Atlantic bluefin tuna on ARKive.

Hannah Mulvany, ARKive Content and Outreach Officer.

Jun 5

As you know, back in May we celebrated our 11th birthday, and to mark the occasion we asked our followers to vote for their favourite Arkive highlight from the past year. A huge thank you to everyone who filled out the survey, it has been fantastic to get your feedback on what we have been doing and to find out what you felt was the most important focus for Arkive.

The results are now in and we are thrilled to announce that you chose our work profiling the world’s most endangered species as your winner. This has been a key aim for Arkive since the very beginning, and today we have over 16,000 species profiles in our collection. Of course, this work wouldn’t be possible without the support of the world’s best wildlife filmmakers and photographers, conservationists and scientists, who contribute their imagery and lend their support and advice.

Why not dive in and discover something new today?

Cotton-headed tamarin

The stunning cotton-headed tamarin is one of South America’s most endangered primates

Our 11th birthday also seemed like the ideal opportunity to give the Arkive website a fresh new look and feel, making the most of our amazing imagery. Check out our beautiful new homepage today.

May 23

The 23rd of May is World Turtle Day – a whole 24 hours dedicated to highlighting the plight of turtle species around the world. Here at ARKive we thought we would celebrate by sharing our top turtle facts.

Did you know…

  • Turtles are found on every continent, except for Antarctica
  • The age of most juvenile turtles can be determined by the upper shell, which grows each year from a central point
  • Turtles are thought to have lived on earth for over 200 million years
  • The sex of most turtle hatchlings is dependent on the temperature which they are incubated at, with males hatching at low temperatures and females hatching when the temperature is higher

Lovely Loggerheads

  • The loggerhead turtle has powerful jaws that can make easy work of its hard-shelled prey.
  • It is highly migratory and is known to cross oceans.

Not a jack in a box

  • Box turtles gain their common name from their hinged shell which enables them to completely close their shell to protect themselves.
  • The male ornate box turtle has enlarged claws on its hindfeet to grip onto the female while mating.

Vast vertebrate

  • The leatherback turtle is the world’s largest turtle, with the average carapace (the shell covering the back) reaching around 160 centimetres and the largest recorded individual weighing up to 916 kilograms.
  • Uniquely, the leatherback turtle is able to maintain an elevated body temperature, giving it the ability to dive to depths of up to 1,000 metres in pursuit of prey.

Snappy by name, snappy by nature

  • The alligator snapping turtle is nicknamed the ‘dinosaur of the turtle world’ due to its prehistoric, alligator-like appearance, from which it gains its common name.
  • The tongue of the alligator snapping turtle has a small, worm-like projection, which is wiggled to attract prey.

What is being done to help?

Thankfully, various conservation organisations and individuals are working tirelessly to help save turtles and tortoises from the brink of extinction. Here are some actions being taken to ensure the future survival of these fascinating creatures:

  • Shrimp fisheries are now using Turtle Excluder Devices, which only allow shrimp-sized objects to enter the nets, preventing turtles from being caught as bycatch
  • Many species are now listed on the Convention on International Trade in Endangered Species (CITES), which means that international trade is strictly monitored and controlled – this should hopefully prevent some collection of wild turtles for the international pet trade
  • Some nesting sites are protected during the nesting season to ensure that eggs cannot be collected and subsequently sold
  • Captive breeding programmes and the protection of areas which are known to support turtle populations could ensure the long-term survival of these magnificent reptiles

Are you turtley in awe of sea turtles? Want to learn more about them? Then why not check out our eggshellent ARKive Education resource – Turtle Life Cycle – and play the turtle-tastic board game!

Find out more about turtles, tortoises and their conservation:

View photos and videos of turtle and tortoise species on ARKive

May 22

Today is the United Nation’s International Day of Biological Diversity, which this year has been dedicated to island biodiversity.

Islands are home to an estimated 20% of all bird, reptile and plant species despite making up less than 5% of Earth’s land area. Islands also contain 40 percent of all critically endangered species, and the extinction rates on islands are disproportionately high despite a global extinction rate that may be 1000 times the historical background rate.

Islands contain 40 percent of all critically endangered species

“Biodiversity is crucial to meet human needs. Our economies, livelihoods, health, and cultures depend on the proper management of this natural capital.  This is even more important on islands where natural ecosystems are fragile and easily disturbed.” said Olivier Langrand, Island Conservation’s Director of Global Affairs, member of the Steering Committee of Global Island Partnership (GLISPA) and co-chair of the GLISPA Working Group on Invasive Alien Species.

The necessity of urgent action in aid of island conservation, to halt and reverse the loss in biodiversity is highlighted in the new publication , “Island Bright Spots in Conservation & Sustainability” by the Global Island Partnership (GLISPA). This report showcases inspired island conservation solutions in action, “bright spots”. These “bright spots” will also be showcased during the 2014 International Year of Small Island Developing States (SIDS) to encourage investment in scaling and replicating initiatives that work. In this publication Island Conservation’s Allen Cay and Small Islands, Big Difference (SIBD) projects are highlighted as successful examples that could serve as innovative models for island restoration around the globe.

Island Conservation’s Allen Cay

Allen Cay, The Bahamas is a small island habitat but is home to important populations of Audubon’s shearwater and provides critical habitat for the endemic, endangered Allen Cay rock iguana. However, invasive house mice were indirectly threatening the native species by providing an abundant food source for barn owls, increasing the owl populations, which predate heavily on Audubon’s shearwater and juvenile Allen Cay rock iguanas. In 2012, Island conservation collaborated with the Bahamas National Trust, Government, NGO and private partners to remove invasive house mice from Allen Cay. This successful partnership protected nationally and globally significant biodiversity, and laid foundations for future restoration and conservation projects in the Bahamas.

Allen’s Cay rock iguana on beach

Island Conservation’s Small Islands, Big Difference Project

Island Conservation’s Small Islands, Big Difference (SIBD) campaign was launched in Montreal, Canada in 2012. The goal of this campaign is to financially support hundreds of partners and island nations in protecting thousands of species through the removal of invasive species from 500 islands.

Island Conservation and local partners helped protect critical habitat for the waved albatross by removing invasive goats and feral cats from Isla de la Plata

The“Island Bright Spots in Conservation & Sustainability” publication also highlights emerging initiatives such as the recent launch of the Mālama Honua Worldwide Voyage by the Polynesian Voyaging Society, a three year open-ocean journey around the world undertaken in two Hawaiian voyaging canoes. The aim of this project is to catalyse awareness and action on how to care for Earth, the Oceans and our natural heritage. The crew aim to bring stories of our islands and oceans to inspire communities and leaders to take action to protect these critical resources.

Read more about the importance of Island habitats on Arkive.

Read more about Island Conservation.

Find out how the Mālama Honua Worldwide Voyage is progressing.

Ben Hogan, Wildscreen ARKive PIPS Intern

May 17
Scalloped hammerhead

Scalloped hammerhead

Species: Scalloped hammerhead (Sphyrna lewini)

Status: Endangered (EN)

Interesting Fact: The hammer-shaped head of the scalloped hammerhead is thought to be a mechanism to spread out the ampullae of Lorenzini which are sensory organs that detect electric currents, chemicals and temperature changes.

More information: The scalloped hammerhead can be distinguished from other hammerhead shark species by the ‘scalloped’ front edge of its head. This species has a relatively slim body and is counter-shaded, with a brown-grey or bronze upperside and a white underside. This relatively large shark can grow up to lengths of 4.3 metres and can weigh up to 152 kilograms. Fish, cephalopods, lobsters, shrimp, crabs, other sharks and rays make up the diet of this species, and prey items are usually eaten whole. Generally occurring in the warm temperate and tropical waters of the Atlantic, Indian and Pacific Oceans over continental shelves, the scalloped hammerhead is also known to enter closed bays and estuaries and generally swims between depths of 0 and 275 metres.

Occasionally caught as bycatch by longline fisheries, the scalloped hammerhead is also caught commercially. Various products are made from the body parts of sharks, including shark fin soup from the fins and vitamins from the liver, as well as the meat which is sold for human consumption. Certain parts of this shark’s range are protected, including the area around Melpelo in Colombia, and there are plans to extend the legal protection to other areas. There are no other known conservation measures currently in place for this Endangered species.

Find out more about marine conservation at the Save Our Seas Foundation and Project AWARE.

Find out more about shark conservation at Bite Back and the Shark Trust.

See images and videos of the scalloped hammerhead on ARKive.

Hannah Mulvany, ARKive Content and Outreach Officer

About

RSS feedArkive.org is the place for films, photos and facts about endangered species. Subscribe to our blog today to keep up to date!

Email updates

Sign up to receive a regular email digest of Arkive blog posts.
Preferred frequency:

Arkive twitter

Twitter: ARKive