Jan 23
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In the News: One quarter of sharks and rays threatened with extinction

A shocking one quarter of all shark and ray species are threatened with extinction, according to the results of a new study.

Great white shark image

The great white shark is classified as Vulnerable on the IUCN Red List

Threat analysis

The paper, published this week in the open-access journal eLife, analysed the threat and conservation status of an impressive 1,041 species of chondrichthyans, a fascinating group of fish species including sharks, rays, skates and chimaeras whose skeletons are made of cartilage rather than bone. The results were rather alarming, revealing that this group is among the most threatened in the animal kingdom.

The paper is the result of collaboration between more than 300 experts from 64 countries, and reports that, while no species has yet been driven to global extinction, at least 28 populations of skates, sawfishes and angel sharks are now locally or regionally extinct. In addition, several shark species have not been seen for several decades.

Reef manta ray image

Reef manta ray parts are highly valued in traditional medicine, posing a threat to this majestic species

Threat hotspots

The study highlights two areas which are currently experiencing a higher than expected level of threat: the Red Sea and the Indo-Pacific Biodiversity Triangle. The latter is considered to be among the most biologically and culturally diverse regions on the planet, yet unfortunately it is also one of the least regulated.

The authors of the paper explain that, “The Indo-Pacific Biodiversity Triangle, particularly the Gulf of Thailand, and the islands of Sumatra, Java, Borneo, and Sulawesi, is a hotspot of greatest residual threat, especially for coastal sharks and rays with 76 threatened species.”

It is feared that, should no national or international action be taken, these species could rapidly become extinct.

Shark finning image

Finning was revealed to be a major threat to many shark species

Major threats

The results of the study revealed that the main threat to chondrichthyans is overexploitation through targeted fisheries and incidental catches. Of particular concern for the future of sharks, wedgefishes and sawfishes is the process of ‘finning’, which is driven by the huge market demand for shark fin soup, a highly sought-after delicacy in China.

The authors of the new research paper state that, “Fins, in particular, have become one of the most valuable seafood commodities. It is estimated that the fins of between 26 and 73 million individuals, worth US$400-550 million, are traded each year.”

Habitat loss is a further threat to chondrichthyans, with 22 species being threatened by the destruction of estuaries and river systems for the purposes of residential and commercial development, and 12 species being placed at risk due to the conversion of mangroves into shrimp farms. In addition, pollution and climate change have been identified as major threats to sharks, rays and their relatives.

Scalloped hammerhead shark image

The scalloped hammerhead shark is classified as Endangered on the IUCN Red List

Additional factors

As well as providing a vital insight into the type and extent of threats to chondrichthyans, the paper also revealed other interesting factors which come into play. It was found that large body size and occurrence in shallow habitat are the biggest factors determining a species’ likelihood of being threatened. The results showed that with every 10-centimetre increase in a species’ maximum body length came a 1.2-percent increase in the probability that the species would be threatened. Dwellers of deep water appear to fare better than their shallow-water relatives, with a 10.3-percent decrease in the probability of being threatened for every 50-metre increase in the minimum depth limit of the species.

 

Read more on this story at Mongabay.com – One quarter of sharks and rays threatened with extinction.

View photos and videos of chondrichthyans on ARKive.

Read more about shark conservation and conservation in the Indo-Pacific Region.

 

Kathryn Pintus, ARKive Content and Outreach Officer

 

Jul 23
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Guest blog: ARKive in the Australian classroom by Barbara Sing

As a Primary Teacher in the Kimberley I have utilised ARKive’s resources over several years as the content is engaging and relevant to the knowledge base of my students; 77% of whom are Aboriginal from many different language groups across the Kimberley; an area three times the size of the UK.

I thought I would share a couple of examples of how I have used ARKive education resources and how they have worked for me and my students.

Keys and classification

Identification keys – sharks and raysWith the implementation of The Australian Curriculum I have found ARKive’s classification resources specifically meet the Year 7 Biological Science content descriptor ACSSU111 which states “There are differences within and between groups of organisms; classification helps organise this diversity” (ACARA).

My students particularly enjoy the ‘Sharks and Rays Identification’ activities as our community is located on the edge of a crocodile infested tidal mangrove habitat and most students engage in recreational fishing and hunting activities. Students of all abilities are able to navigate the identification keys easily and the accompanying presentations on shark and ray identification and classification resources make the lesson preparation seamless. The other activities provided engage students over a series of lessons and I normally conclude the unit by getting my students out of the classroom with a visit to a Munkayarra Wetland. During the visit students use an identification key similar to the ARKive keys to identify macro invertebrates they collected.

Students using classification keys at Munkayarra Wetland © Barbara Sing

Students using classification keys at Munkayarra Wetlands

Human Impacts on the Environment

Human Impacts on the Environment education resourcesAlthough my students have some idea of the impact of plastic in the marine environment the ‘Human Impacts on the Environment’ resource was certainly an eye opener for many of them. The module explores the different ways humans can have negative impacts on the environment and endangered species. I recommend it highly as a resource for Sustainability, Science as a Human Endeavour and also Chemical Science.

Spreading the word

I easily keep up to date with new resources through the ARKive facebook page and share the resources with other teachers and environmental groups.

Thanks for providing a growing useable resource for teachers globally!

Barbara Sing Derby District High School (K-12), West Kimberley, Western Australia

Jun 18
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In the field: The Manta Trust

Manta ray photoWhile the oceans of our planet cover more than 70% of the Earth’s surface, we still know so little about what goes on beneath the waves.  There are vast areas, great depths and even hundreds or perhaps thousands of species that we still barely understand.  Manta rays can certainly be classed as one such species that we know little about and that is why in January 2012, The Manta Trust came into being; a UK registered charity aiming to improve our understanding of these animals and promote their long-term conservation.

What is the Manta Trust?

Manta Trust LogoThe Manta Trust is a growing group of scientists, photographers, film-makers, conservations and advocacy experts who have joined forces to co-ordinate global research and conservation efforts for both manta rays and their close cousin’s, the mobula rays.

Manta ray photoThese rays are among the most charismatic creatures that inhabit our oceans. With the largest brain of all fish, their intelligence and curiosity is often compared to that of a large mammal, making encounters with them a truly unforgettable experience.

However, despite their popularity with divers and snorkelers many aspects of these creature’s lives remain a mystery, with only snippets of their life history currently understood. More worryingly, in recent years a targeted fishery for these animals has developed, causing devastating declines in global manta ray populations.

The Manta Trust brings together a number of research projects from around the globe. By conducting long-term, robust studies into manta populations in these varying locations, we aim to build the solid foundations upon which governments, NGOs and conservationists can make informed and effective decisions to ensure the long term survival of these animals and their habitat. By coupling this research with educational programmes and raising awareness, we hope to be able to make a lasting difference to the future of our oceans.

What are manta rays?

Manta and mobula rays are cartilaginous elasmobranch fishes. Like other rays this means they are a close relative of the shark. However, unlike most rays which spend at least a portion of their lives hugging the seabed, mobulids live pelagic existences – meaning they spend their time swimming in open water.

They’re also completely harmless to humans, feeding on zooplankton, the often microscopic animals which live in the water column and are the base of many ocean food chains.  This food source means that these amazing rays are at the mercy of the oceans, often migrating thousands of kilometres to track down their next meal!

Manta ray photo

Manta rays are also the largest rays in the world.  There are two species of manta, the reef mantas and the larger oceanic mantas that grow to over 7m diameter from wingtip to wingtip.

We believe manta rays to be incredibly long lived, probably living to at least 50 years old or possibly longer! This characteristic, coupled with the fact that they mature late, reproduce infrequently and give birth usually to a single pup at a time, make them very vulnerable to exploitation by fisheries.

Are there any threats to mantas?

Gill plate photoUnfortunately yes, manta and mobula rays are fished for their gill plates, the intricate apparatus which helps them to both breathe underwater and to strain their microscopic planktonic food from the water.

This fishery is quite a recent development, with the gill plates being sold in Asian markets where they are prepared as a tonic to treat a variety of ailments.

Due to the vulnerable nature of these animals this has the potential to have catastrophic implications for their fragile populations.  In fact populations in some areas have already seen declines of up to 86% due to fisheries.

Where does the Manta Trust work?

One of the main aims of the Manta Trust is to unite and co-ordinate work being undertaken with these rays in all corners of the globe.  So far we are working in 17 countries!  By co-ordinating our research in this way the hope is that we can share in each other’s successes (and failures), learning what works and what doesn’t, ultimately achieving global successes for these species.

What does the Manta Trust want to achieve?

Our vision is “A sustainable future for the oceans where manta rays thrive in healthy, diverse marine ecosystems.”  We’d like to achieve this by conducting robust scientific research whilst educating and raising awareness of the issues which face these animals.

We know that good conservation requires a holistic approach. Therefore the Manta Trust researchers and volunteers work closely with tourists, local communities, businesses and governments to ensure the preservation of these amazing animals through a combination of good science, education, community based initiatives and government legislation. As the scope of the Trust’s work continues to grow our goal is to keep expanding these efforts globally.

In March 2013, the Manta Trust was part of a consortium of NGOs behind the successful listing of both species of manta ray on Appendix II of CITES (Convention on International Trade in Endangered Species of Wild Fauna and Flora).  This listing means trade in manta ray parts between the 178 signatory nations will be closely controlled and restricted when this legislation comes into force in September 2014.

Manta Trust photo

This is a huge victory, however much still needs to be achieved for these animals until this legislation comes into force, especially to aid those in the involved fishing industry to transition to more sustainable futures.

How can you help The Manta Trust?

Manta ray photoOne of the best ways you can help is to swim with mantas! By showing governments that manta-based tourism is important and that it provides a sustainable long term industry in which people can earn a living whilst co-existing with these animals, we will be taking positive steps towards long-term solutions for these rays.

If you’ve been lucky enough to swim with mantas why not send us your pictures?  Each manta is uniquely identifiable by the pattern of spots on their ventral (belly) surface.  We are collating manta images from around the world as part of our global IDtheManta database.

You can learn more about it here.  By collecting this information on a global scale we hope to learn more about these amazing and mysterious animals.

We also accept volunteers! Check out our Volunteer page on The Manta Trust website and follow us on Facebook to see the latest opportunities as they are announced. In fact following our work on our blog, website, Facebook and Twitter pages and sharing what we do with your friends is also an amazing way to spread the manta message!

Dec 8
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The ARKive Team’s Favourite Species

The sleepless nights are beginning to show amongst the ARKive team as they decide which species is ahead of the pack. Our last revelation was by Rebecca Taylor with her love for the sensational sea otter, but will this week’s team member favour cuddliness or mind-blowing biological ability?

Rebecca Moran – ARKive Species Text Author

Favourite species? Manta ray

Why? I think I’m mainly fascinated by the manta ray because of its sheer size! It can measure a whopping 6.7 metres across, which would be roughly equivalent to four of me (or any lady of average height!) laid end to end! In spite of its size, the manta ray is extremely graceful, using its large wings to seemingly fly through the water while feeding on tiny planktonic organisms. I’d definitely love to don some flippers and have a snorkel with a manta ray some day.

Favourite image on ARKive:

Photo of manta ray

Manta ray swimming

The manta ray (Manta birostris) is listed as Vulnerable (VU) on the IUCN Red List, and is currently threatened by fishing, both intentionally and as accidental bycatch. This species is now protected in many areas, with total fishing bans imposed by some countries.

See more photos and videos of the manta ray.

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