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Sharks and rays threatened worldwide – overfishing to blame

We have heard a lot of about sharks recently. In particular Western Australia’s plan to cull threatened white sharks has stirred up plenty of protest from the community, and a frenzy of media coverage…

Sawfish are the most endangered members of the shark family. Flickr/Kaptain Kobold

We have heard a lot of about sharks recently. In particular Western Australia’s plan to cull threatened white sharks has stirred up plenty of protest from the community, and a frenzy of media coverage and commentary (see Conversation articles here and here and here).

But new research is showing that there are hundreds of species of sharks and rays that face an increased risk of extinction, not just the couple of species that grab the media spotlight.

A new study published today in the journal eLife has for the first time estimated the risk of extinction across all 1041 species of sharks and rays that make up an entire class of vertebrates. This first-ever study undertaken by the International Union for Conservation of Nature (IUCN) Shark Specialist Group took the expertise of over 300 scientists around the world to complete.

Bleak picture

The results paint a bleak picture of the status of this important group of ocean predators. Approximately one quarter of the known species are estimated to be threatened according IUCN Red List categories and criteria, mostly as a result of overfishing.

Possibly even more concerning is the result that 47% of species were assessed as Data Deficient, meaning that we don’t have enough information to properly assess their status. Clearly there is a need for a lot more science to help manage a group that is obviously under threat.

Many people who hear these grim statistics will think of shark finning (where the fins of sharks are cut off at sea and the bodies dumped) as the likely reason for the declines. While finning is a major factor in the decline of some populations it is far from the main reason that many of these species are threatened with higher chances of extinction.

We don’t know nearly enough about thresher sharks. All three species are listed as Endangered on the IUCN Red List. Flickr/Raven_Denmark

Why? Because more of species that are globally threatened are rays (107 species vs 74 species of sharks), most of which do not have fins suitable for the fin trade. Incredibly, five of the seven families that are most threatened are rays. One of the shark families is the angel sharks, which also have flat, ray-like bodies.

Warning signs

That there is such a crisis for rays has come as a shock, even to many involved in the study. Could we have predicted such a perilous status for rays? Possibly.

It turns out that since the mid-1970s the landings of rays reported to the UN Food and Agriculture Organisation has consistently been higher than sharks. So now the challenge will be to get the rays the attention that they need so that we can start to address these declining populations.

The benefit of the global analysis is also that we can identify geographic regions where the threats are greatest. The three areas where humans have had the greatest effects on shark and ray populations are western Indonesia/Thailand, the Red Sea and the Mediterranean Sea.

While these three areas are the hotspots of concern, there is nowhere that sharks and rays have not been affected – this is truly a global problem. So while some countries have worked hard to secure the future for many of their shark and ray populations (such as Australia, New Zealand and the US) by having science-based catch limits, many others have little or no regulation.

Reversing the trend

Given the diversity of the species, and differing capacity of countries, reversing the declines of sharks and rays will not be simple. Some countries have well developed science-based management while others lack the resources for comprehensive or even basic fisheries management.

Angel sharks might not have valuable fins, but they are still targeted. They’re the second most threatened group of sharks. Flickr/Philippe Guillaume

Few situations, however, would not benefit from improved data collection, particularly with respect to prompt and accurate reporting of species-specific catches.

Through the International Plan of Action for Sharks, the UN Food and Agricultural Organisation provides not only directives for completing valuable national and regional plans, but also technical guidance and the promise of more tailored assistance toward conservation for developing countries.

Globally, completion and full implementation of these key plans remains patchy. Their development, however, should not stand in the way of the urgent need to control – and in most cases – reduce fishing mortality of sharks and rays (from targeted and incidental catches). While these challenges may seem daunting, key steps can make a difference.

The real take home message from this new study is best summed up by Sonja Fordham, IUCN SSG Deputy Chair and president of the Washington, DC-based Shark Advocates International, a project of The Ocean Foundation:

Significant policy strides have been made over the last two decades, but effective conservation requires a dramatic acceleration in pace as well as an expansion of scope – to include all shapes and sizes of these exceptional species. Our analysis clearly demonstrates that the need for such action is urgent.

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19 Comments sorted by

  1. Wade Macdonald

    Technician

    This article would be better if it didn't use emotive terms like 'crisis' then make a statement like this...

    "Possibly even more concerning is the result that 47% of species were assessed as Data Deficient, meaning that we don’t have enough information to properly assess their status. Clearly there is a need for a lot more science to help manage a group that is obviously under threat."

    then straight after state...

    "Many people who hear these grim statistics"

    If you don't know the status of half the species out there because of a lack of science then you cannot also claim that things are in crisis or grim or under threat.

    You either know or you don't know!

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    1. Brad Farrant

      Adjunct Research Fellow in Early Childhood Development at University of Western Australia

      In reply to Wade Macdonald

      Wade,

      Perhaps you missed this bit - "The results paint a bleak picture of the status of this important group of ocean predators. Approximately one quarter of the known species are estimated to be threatened according IUCN Red List categories and criteria, mostly as a result of overfishing."

      My understanding is that in addition to the quarter of species that estimated to be threatened there could be many more in the "47% of species were assessed as Data Deficient".

      Justifies the crisis tag for me.

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    2. Wade Macdonald

      Technician

      In reply to Brad Farrant

      Yes the same IUCN list that puts many animals on the threatened list but doesn't truly know there status. Southern bluefin tuna in NSW are classed as threatened but the reality is that bluefin have only ever been seasonal to NSW and the population varies with ocean currents, temperature variability and many other factors. The species was only ever transitional yet climate change is ignored over blaming fishing and models under estimated the biomass by 30%.

      It seems this article and and many others are quick to call overfishing as responsible even here in OZ. To few people are aware that pollution in particular and the resultant habitat loss are major contributing factors as well as natural variation.

      I can't speak about overseas matters but here blame is often misplaced on fishing.

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  2. Neville Mattick
    Neville Mattick is a Friend of The Conversation.

    Grazier: ALP Member at A 4th Generation Grazing Station

    Thank you for this depressing article Colin and I mean that in a very good spirit of the education it brings.

    Personally I rarely eat anything (knowingly) from our Ocean's and totally despise Cats.

    I reckon since we swim in their space - we are fair game!

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    1. Michael Shand

      Software Tester

      In reply to Neville Mattick

      I too have stopped buying sea food, I cut down on other meats as well.

      Of course, if I attend a BBQ and the host has already bought the prawns then me eating them or not makes no difference and so I chow down

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    2. JB Rawson

      Writer

      In reply to Michael Shand

      Although, Michael, if you say no thanks and then explain why you'd rather not eat the prawns, next time your host might not buy the prawns either. Or, the host might beat you with a stick and tell you to lighten up.

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    3. Michael Shand

      Software Tester

      In reply to JB Rawson

      Much of my social circle are just mindlessly apathetic about everything.

      NSA targeting academics that hold unfavourable political views as revealed by snowden.....ehhhh, doesn't bother them

      Climate Change degrading the quality of life and threatening the survival of our species, Koala expected nearly extinct in 2050 due to heat....ehhhhhh doesn't bother them

      Income Inequality affecting hundreds of millions, no politician even attempting to address tax havens or loop holes for decades, inhumane…

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    4. JB Rawson

      Writer

      In reply to Michael Shand

      It is hard to know when to speak up and when to be considerate of other people's feelings...

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    5. Wade Macdonald

      Technician

      In reply to Neville Mattick

      Neville if rays around southern Australia are endangered then I must be living on mars. There are rays everywhere, so much so it's often no point trying to catch finfish in some regions.

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    6. James Hammond

      Ecologist

      In reply to Wade Macdonald

      Anecdotes are just that.

      Do these abundant rays represent a cross-section of all species that occur in Australian waters?

      Could the rays that you see belong to the few generalist species that do well even with significant disturbance?

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    7. Wade Macdonald

      Technician

      In reply to James Hammond

      Sure the species I am talking about are widespread and not confined to specific bays or estuaries like others. However, these species that are only known to exist in small specific areas are prone to extinction, biomass variation from our landbased activities or natural, man made disasters.

      SA doesn't bottom trawl our two gulf systems within 3nm from the coast but we do have major problems with degradation of habitat.

      The categories in the IUCN redlist are rigged. 6 terms of threatened level categories, 1 neutral and two infer no research. To sway statistics I could put in 6 positive terms and 1 neutral term and claim sharks and rays are in a great state globally.

      Have a look at the category terminology yourself as to deny its bias is to deny an obvious agenda being pushed.

      http://www.iucnredlist.org/details/60122/0

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    8. James Hammond

      Ecologist

      In reply to Wade Macdonald

      "The categories in the IUCN redlist are rigged. 6 terms of threatened level categories, 1 neutral and two infer no research. To sway statistics I could put in 6 positive terms and 1 neutral term and claim sharks and rays are in a great state globally.
      Have a look at the category terminology yourself as to deny its bias is to deny an obvious agenda being pushed"

      I really can't comprehend what this means. There are 6 possible categories of 'extinction risk' that a living species can fall into…

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    9. Wade Macdonald

      Technician

      In reply to James Hammond

      Near threatened eh?

      Near plague...where is that one?

      Give me a break, if you are going to go research something it's the species that needs it the most.

      So what category do we place mice in when the mouse plague is over and numbers are 5% of last years abundance?

      Do we claim it must be those nasty farmers again! That is what I suspect is going on here with this article.

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  3. JB Rawson

    Writer

    So I should add skate to my list of fish to not eat, alongside 'flake'?

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    1. Wade Macdonald

      Technician

      In reply to JB Rawson

      From some parts of the world you can say no but most local seafood including flake (usually gummy shark) is caught from a sustainable fishery.

      It's easy to ban yourself through fear of what you don't understand so you asked a good question.

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  4. Andy Saunders

    Consultant

    I suspect the bottom picture is of a wobbegong, not an angel shark...

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  5. Imelda J

    RN Bsc Dip Journ

    I would like to see all wildlife placed on a Threatened Species List, and only taken off the list when it is proved they are not at risk.

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    1. Wade Macdonald

      Technician

      In reply to Imelda J

      Are you inferring that we should remove all the categories on the IUCN list that don't reflect a threatened status level and just claim its all threatened to push agendered statistics?

      And I thought the IUCN were worse than Australian environmental zealots. Clearly the IUCN are only conservatively bias then.

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