100 million sharks killed each year? Research vs. “magic numbers”

According to research published in 2006, an estimated 26 million to 73 million sharks are killed annually for commercial markets. While this number differs from the 100 million figure that is widely used in the media, it is based on scientific research, which still indicates that tens of millions of sharks are killed annually.
An estimated 26 million to 73 million sharks are killed annually for commercial markets, research shows.

It seems the magic number of 100 million sharks killed each year gets quite a bit of use in the world of shark conservation, but is there any actual data to support this number? At least one commenter on this blog has called the number into question, which led met to start looking into the basis for the 100 million “statistic.” Other shark conservation-minded bloggers including Shark Diver’s Underwater Thrills and Luke Tipple have called the 100 million number into question this year, due to a lack of a scientific basis for the number. Despite the lack of any hard data to support the number it is widely used and accepted in the media and in many conservation efforts.

Research conducted by Shelley Clarke estimated the global number of sharks killed annually at 26 million to 73 million. Clarke’s Global Estimates of Shark Catches using Trade Records from Commercial Markets journal article published in 2006 in the Ecology Papers Vol 9 Issue 10 follows a generally accepted scientific methodology and is backed up by solid research.

While “26-73 million” might not roll off the tongue quite as easily as “100 million,” there is data to support the former, while there seems to be no solid data supporting the latter. Considering that I make a point of calling attention to instances of misrepresentation and misinformation in the media with this blog, I think it’s important to point out that the use of the 100 million number is not based on any specific scientific evidence, and I would encourage shark conservationists to reference the global estimates from Clarke’s research. At the end of the day, even the low-end estimate, from Clarke’s study, of 26 million is still alarming number of sharks being plucked from the ocean.

The other lesson to be learned from the lack of scientific data to back up the claim of 100 million sharks killed per year, is that opportunistic filmmakers will use the baseless number as springboard to devalue the entire shark conservation effort, as can be seen in the video below.

The gentlemen in the video have a point when it comes to the magic “100 million” number (and the “90% of the species” statistic), but nowhere in the video do you hear mention of the estimates from Clarke’s study, which would be far less disputable.

When it comes to shark conservation efforts, I recommend sticking with data that can be backed up by science. There’s already enough conjecture and flat-out misinformation out there without shark conservationists adding to it (as a couple of the people in the video above do a fine job in displaying).


  1. nick blackman says:

    When the bulk of shark finning is happening illegally and is sold on the black market why would anyone assume those figures would show up in data for commercial markets. Mafia driven illegal shark finning is not a commercial enterprise and would not go reported as such. If the declared commercial catch rates are horrifically up to as much as 73 million then I would imagine the undeclared catches to put the figure way above even 100 million. It was only in 2002 that the United Nations realized the world catch of global fishing markets was actually going down and not going up. This was due to misinformation and false reporting from the chinese officials -the reality is never going to come out in entirety in any data sheet. Out of sight and out of mind. The majority of what happens to OUR seas goes unnoticed and unreported but it is happening and it has to stop. Whatever the figure may really be I couldnt care less – I know in my blood that sharks are being decimated and I know as a fact that sharks regulate the oceans. I also know as a fact that the oceans regulate our climate as well as absorbing most of our carbon dioxide as well as providing two thirds of the oxygen we breath. If the sharks go and the ocean eco system collapses we may have lost the battle outright and take 90% of life on earth with us on the way out. Not convinced? are you really prepared to take a gamble?? Is it worth gambling over??? You cannot play dice with biology. If in twenty years you stand on a shore with your children looking out over a potentially massively different ecosystem and quality of life for everything and they ask if you were part of the problem or part of the solution what will you say?? But I wasnt sure the figures were right???????

    • George says:

      The whole point of this post is to counter the argument made by those who say that there is no threat to sharks, because the “100 million” number is made up. The fact that this number is unsubstantiated has been used by some as a platform to argue that there is no proof that sharks are being killed by the millions, annually.

      The point of this post is to assert that while the “100 million” number isn’t backed by research, there is, in fact, scientific evidence to suggest that sharks are being killed by the millions for commercial markets, and it’s presented in Clarke’s Global Estimates of Shark Catches using Trade Records from Commercial Markets.

      So, given the option of using a figure that has no research to back it up (which can then be called out as unsubstantiated by those who oppose shark conservation efforts) versus using a figure that it is backed up by research, it is suggested that those who are concerned with responsible shark conservation would opt to use the figure backed up by research.

      At no point in the post was it ever suggested that we should ignore threats to healthy shark populations, regardless of which figure is used.

  2. TAASFA says:

    20 million, 73 million, 100 million whatever the number is it is too many. That’s the point and the point people trying to discredit shark conservationists want to push. They accuse shark conservationists of quoting numbers of sharks killed and/or finned as misleading, but the fact is the numbers are elastic and that is acknowledged. Don’t be put off by the likes of the Shark Con team and Howard Sawyer who are fixated on figures when the real fact is we are losing sharks from our oceans at an unsustainable rate and in a manner most lacking of the basic of animal welfare requirements. Shark Con & Sawyer would be better off counting grains of sand than interfering in the valuable work of shark conservationists.

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