Should scientists avoid publishing shark migration data because it helps fishermen? Spoiler: No


I work with a lab that satellite tags sharks to study their migration patterns, such as this large female tiger shark in the Bahamas

Our lab satellite tags sharks to study their migration patterns, such as this large female tiger shark in the Bahamas. Note the tag on the dorsal fin

In recent weeks, some conservation activists have been promoting an idea that I would like to respond to as a member of the scientific community. They claim that scientists shouldn’t publish data about shark migrations, movement, or population dynamics because such data helps fishermen to find areas where there are lots of sharks and kill them. This  misguided anti-science paranoia demonstrates a fundamental lack of understanding about how conservation policy works.

Fishermen are neither having trouble finding sharks nor relying on the scientific community to learn where they are. In fact, this is exactly why such studies are needed.

Shark migration and habitat usage data are critical to developing effective management plans. One of the ten guiding principles of the U.N. International Plan of Action for Sharks is to “determine and protect critical habitats.” As we can’t stop all shark fishing in the entire ocean*, the goal is to identify the most important habitats (i.e. nursery areas, mating aggregation locations, etc).  and focus conservation efforts on those. We can’t effectively protect sharks if we don’t know where they are, when they are there, and (ideally) what they are doing there.

Detailed data on population dynamics are critical for developing science-based sustainable catch limits. If managers don’t know how many sharks are in a population, they can’t accurately determine how many can be sustainably fished (and in many cases, just saying “don’t fish for them at all” is a cop-out that ignores the reality of the situation*).

Finally, detailed population data is also necessary for determining which species are the most threatened. If we weren’t monitoring population sizes, we wouldn’t know that some species are in need of additional legal protections. Indeed, most strong legal protections (Endangered Species Act, CITES, certain RFMO rules including quota reductions, etc) can’t be implemented without detailed scientific data showing that the species is declining in population.

Without scientists studying and publishing data on shark migration patterns and population dynamics, conservation policy would be crippled, but commercial fishing would still be doing just fine.

*Yes, I am aware that some countries are Shark Sanctuaries where no commercial fishing for sharks is allowed. If fishing is prohibited in an area, it’s unclear what negative impacts the publication of tracking data could have. However, most countries are not Shark Sanctuaries, and many areas, including international waters, will never be. If your goal is “no one in the world ever fishing for sharks anywhere” rather than protecting particularly threatened species and opposing unsustainable overfishing, you’re going to be disappointed.

For more information on the applications of satellite tags to shark research, please see our lab’s review paper on the subject.


  1. Chuck Bangley · July 1, 2013

    It’s been my experience that almost 100% of the time the fishermen already know the sharks are there. Heck, most of the sharks I’ve tagged were caught in areas fishermen told us about (and areas they avoid because they’re not allowed to keep those particular species). Even the most field work-loving scientist is never going to get out on the water as often as a full-time fisher, so the idea that somehow we’re keeping sharks safe by not publishing where they’re at is laughable at best.

  2. Brian · July 1, 2013

    Excellent rebuttal. I’ve heard that argument before but always had a hard time believing that fishermen use scientific data to figure out where to fish for their target species. I’m sure they have a pretty good idea.
    Isn’t that also part of the problem with this kind of activism? It demonizes commercial fishermen instead of looking to collaborate with them. I would imagine that many fishermen have a different kind of knowledge that could be very useful to the scientific community.

    • David Shiffman · July 1, 2013

      Many scientists are collaborating with commercial fishermen. And by collaborating, I mean what you describe, not “telling them where the sharks are so they can go kill them all”.

    • Mike McCallister · July 2, 2013

      We collaborate heavily with commercial fisherman for lots of our reproductive biology research. In fact the grants that fund the work REQUIRE a commercial fishing partner in order to be considered for funding. We charter them and/or pay them for sharks that they catch. They are already gonna catch them anyway (and know where to go to get them!)…we use that to be able to help us collect samples when we are unable to fish, or in areas we can’t get coverage from.

  3. Pauline Devine · July 1, 2013

    I’m not sure if publishing this data does add to the numbers of sharks killed by fishermen. But I am sure they have a perfectly good idea where to find them for themselves but what about when they’ve depleted a ‘stock’ of sharks at a specific location and they need to move on to another known habitat, scientific data may come in useful then? And what about non-commercial shark fishing for sport? This is for pleasure and the so-called thrill of it. Do we really want to add to numbers killed by this purely selfish pursuit? Why do fishermen or anyone else need to know the scientific facts? Keep the scientific data among the scientists. Let them interpret and cascade down where and how many sharks can be caught. Although why it’s necessary at all is beyond me. The ocean or it’s inhabitants are not there for us to plunder, they simply exist like we do. I’ve never eaten shark in my life, I have far too much respect. Shark fishing exists for monetary gain and pleasure alone. And if it’s a cop out to wish shark fishing didn’t exist then I may as well just lay down and die right now and stop fighting against everything I believe is wrong.

    • David Shiffman · July 1, 2013

      “Why do fishermen or anyone else need to know the scientific facts? Keep the scientific data among the scientists. Let them interpret and cascade down where and how many sharks can be caught”

      This is a remarkably inaccurate description of how science works.

      ” And if it’s a cop out to wish shark fishing didn’t exist then I may as well just lay down and die right now and stop fighting against everything I believe is wrong.”

      You can “wish” whatever you want, but it’s willful ignorance of reality to think that this could happen on a global scale.

    • Megan · July 2, 2013

      Science shouldn’t be contained to scientists when so many of the applications for scientific data lie in other fields. Specific to this article, policy making and commercial fishing can both use this information (hopefully in order, policy before fishing). If policy is made protecting regions and species, then it is from the sharing of scientific data that commercial fishers can harvest marine life within the scope of regional/national laws.

    • Austin · July 1, 2013

      Just a quick note to Paula that sort of underscores the entire message of the article.

      “Keep the scientific data among the scientists.”

      This is a very dangerous and Renaissance-era idealogy. Communicating science beyond simply the scientific community has become increasingly important practice, and is especially common among the newer generation of scientists and graduate students. Many scientists don’t – and won’t – sit in an ivory tower anymore – the information needs to get out there. The fisherman are the easiest (and incorrect) scapegoat in this scenario. Instead, I would argue that greater conservation and awareness would be achieved by sharing shark migration data. It is an awesome tool in which people can feel like they are part of the discovery.

      Tracking animals like sharks with sophisticated real-time technology can be one of the most fascinating aspects of animal conservation, and we scientists aren’t the only ones who think that. I have had many experiences with fishermen, the public, relatives, strangers, bartenders, and even flight attendants who are just as amazed to learn about where our animals are going and why they may be doing so.

  4. Dashark · July 1, 2013

    That’s a remarkably inaccurate description of how the real world works! 🙂

    With all due respect, you (once again) make generic statements that are obviously based on your experience in the US.
    The fact is that the vast majority of countries are nothing like the US in that any management of fish stocks, let alone sharks, is nonexistent to woefully inadequate as amply demonstrated by the global crash of stocks.

    As an example, I can promise you that if I published the time and location of fish spawning aggregations throughout Fiji in the local press, every single Fijian fisherman would cough up the money for the fuel and drive there. And whereas the local fishermen may well know of, and exploit the event, that additional pressure would be simply devastating. In fact, those researchers studying spawning aggregations in the developing world make it a point to never publish the precise coordinates.
    Same-same for divulging the location of natural shark aggregations, something we in the shark diving industry have learned the hard way insofar as many of the original shark diving sites have been fished out because they were publicized but not protected.

    As you hopefully know, I don’t indulge in anti-science paranoia.
    I’m all for collecting those data that I consider to be vital, like I suspect are most (educated) shark conservation activists; and contrary to many of them, I’m also very much in favor of well managed shark fisheries.
    But I share their reservations that are not against the science per se, but against the publishing = publicizing of the data in cases where there is no adequate management – which globally is the overwhelming majority, this notwithstanding of the (voluntary) IPOA-SHARKS that is generally not, or only poorly implemented.

    Blog post here

    • David Shiffman · July 2, 2013

      Thanks for commenting, Mike.

      Nothing that you’ve said changes my central point, “Without scientists studying and publishing data on shark migration patterns and population dynamics, conservation policy would be crippled, but commercial fishing would still be doing just fine.”

      I’m not explicitly objecting to the idea that publishing data could possibly result in some individual sharks being fished, though this isn’t a common occurrence in the grand scheme of things. Some fishermen may move to exploit a newly publicized system if appropriate policy safeguards aren’t put in place (I’m sure several of us have anecdotes about this happening on a small scale), but it’s not like that couldn’t happen otherwise. Fishermen find aggregations sites on their own all the time. Most fishermen I talk to know a lot more about where sharks (or whatever fish they catch) are then scientists, divers, and conservationists do, which makes sense- there are more fishermen and more fishing boats than there are scientists and research vessels, and they’re out every day.

      What I’m objecting to is the converse- that by not studying these things and publishing the data, you’re helping sharks somehow. The reality is that not studying important aspects of shark biology and ecology (and by important, I mean research priorities identified by teams of expert natural resource managers and scientists, not what you personally “consider to be vital” ) leaves us ill-equipped to make effective science-based policy decisions. Not studying where sharks are is protection only until someone randomly stumbles upon them, but science-based policy, if well designed and well enforced, keeps the species protected long-term.

      To be sure, different places have different rules. My experience is based in the U.S. and the Western World, but I regularly communicate with scientists and NGO experts elsewhere and am well-read on global fisheries and conservation policy. For example, Fiji, as you may know, is in the process of (and from what I hear, almost done with) adopting an NPOA-sharks based on the IPOA-sharks guidelines I linked to above. Fiji is also a participant in RFMOs that require this kind of data in order to implement conservation policies (areas where fishing is banned, seasonal closures, reduced quotas, etc.) The U.S. and the E.U. also donate a great deal of money and technical expertise to the developing world to help with capacity building.

      As far as making sure those guidelines are implemented and enforced goes, there’s a big role for local NGOs as well as local activists like yourself.

    • Dashark · July 3, 2013

      Hah – may I be smelling somewhat of a straw man here? 🙂

      Granted there is an extreme fringe out there – the most egregious example being the pseudo- and anti-scientific nonsense spouted by some of those frothy anti-OCEARCH fanatics.
      If you are addressing those stupidities, totally agree.

      But in general terms, the more pragmatic, educated Shark conservation activists (yes it may sometimes seem a contradiction in terms but they do exist!) are all in favor of research into philopatry and population dynamics, and often even finance, enable and partake in it – yours truly being one of them!

      Your central point, I believe, is not the contentious issue here.
      As per my post linked above, some people including me question the wisdom of publishing those near- or real-time tracks – not always but certainly in some cases.
      Yes they are great outreach tools and certainly make donors happy – but they are essentially raw, unfiltered data that lack any mediation by the researchers (until which time they are also not yet adequate tools for formulating management and conservation policies), and they are inherently susceptible to abuse.

      Your tracks are probably unproblematic as your Sharks are likely to be migrating within relatively well managed waters – but how about the following.

      IMO, the tagging expedition of GWS in SA by OCEARCH et al was extremely important, albeit I believe being unnecessarily brutal and not adequately flanked by an according education campaign among the local populace.
      I understand that we know very little about the life history of those Sharks, especially when it comes to their nurseries, and if the life history of the NE Pacific GWS is any indication (which is not necessarily a given), possible mating and offshore foraging aggregations.
      From (most likely incidental) catches in Mozambique, we know that some Sharks visit that country where they are not protected, but we lack the data to determine the extent, frequency, reason and final destination etc of those migrations and are thus unable to formulate adequate protection policies there.
      With that in mind, satellite telemetry appears to be the ideal vehicle for filling those knowledge gaps.

      Now those tracks are online and thanks to OCEARCH’s stellar technology, I and everybody else discovers that, say, Kathryn is presently just offshore Taolagnaro, Southern Madagascar.
      I’m not saying that some nefarious fisherman will rush there and kill her – but what if Toalagnaro, or some reef in Mozambique were a newly discovered major aggregation site, and all SA GWS migrated there at some predetermined time – wouldn’t it be better to withhold that information pending the establishment of adequate conservation measures?

      Remember that the SOFA was not discovered by fishermen but by satellite telemetry – but those first tags were PATs, the data thus delayed and first mediated by the researchers, and luckily, the area is way too large and remote to warrant any targeted fishery.

      Or MDs app.
      Apparently, there may be a newly discovered GWS nursery in Mexico, a country where on top of plenty of incidental catches of juveniles, there is an illegal targeted trophy fishery for large GWS – publicize it, or set in place proper conservation measures first?

      I’m sure you hear me.
      Like many if not most of my peers, I’m thus not at all anti-SPOT-tagging, let alone anti-science – I just believe that like always, one has to weigh the pros and cons and that sometimes, it may be advisable to exert an excess of caution.

      Or am I missing something here?

      The Fiji NPOA?
      I could write entire books about it and am highly skeptical – that being the euphemism of the year!

      But the proof is of course in the pudding
      So far, Fiji has been officially exporting 130mt of fins/year, all apparently from “bycatch” largely by the foreign distant water fleets – read this.
      So, let’s see the next batch of numbers – anybody taking bets?

  5. Simon Pierce · July 2, 2013

    This is a great topic! I’m hearing this concern raised more and more…

    We were regularly working with commercial fishers in Australia, and they know a lot more about where to find specific (commercially-targeted) species in different seasons/conditions than we could ever learn over the course of a regular scientific project. By working directly with the fishers, there was a hugely positive knowledge transfer – but most of the knowledge on shark movements was coming from them, not us.

    Things do work differently in the developing world, but there’s still a major benefit to helping fishers have a better understanding of the system, and vice-versa.

  6. Dashark · July 2, 2013

    @Simon: absolutely!
    The ideal end result of our efforts is that everybody agrees on sustainability, the more as it is beneficial both to the fishermen and to conservation alike – and of course reaching that agreement implies having a dialogue and exchanging information, etc!

    But were you to discover, say, a new Manta cleaning station off Tofo – would you proudly post it in some paper and in the media, or would you maybe try and get it protected first?

  7. Ila France Porcher · July 3, 2013

    I think that what you are interpreting as an attack on science, is simply the recognition that science is objective, and seeks the truth. Whether the scientific findings will be used for “good” or “bad” lies with others, and over this use, the scientist has no control.

    The method used by the scientific community today involves publishing in journals, and the information is freely available. Further, since scientists are judged by the number and quality of papers they publish, there is quite a pressure to do so. Have you ever heard of a scientist who would refuse to publish information just because it would be used to kill sharks?

    They would quite rightly say that as scientists, how their information is used is of no concern to them. Animals, including sharks, have always been killed in large numbers for science, and the state of the world as it is today, dominated by one species, in which the others are used for its benefit, has come about with the constant support and help of mainstream science, working hand in hand with fisheries, industry, etc., even though the resulting situation is not beneficial for the biosphere.

    Instances in which scientific findings have been used for destructive purposes are legion, and most of them were not foreseen by the scientist who initially made the discovery. For example, it is very unlikely that those who worked out the principles of quantum mechanics could have foreseen the atomic bomb resulting from their work, even in their worst dreams.

    So the problem is the pretense that the information will be used for shark protection, when in fact the scientist has no power to protect the sharks at all, and the information is more likely to be used to kill them, than to protect them, given the natural behaviour of our species.

    And the information is used to kill them. Shark fins are the most valuable sea food, and money is god. Therefore, wherever sharks are, there are going to be people with dollar signs in mind, trying to kill them.

    Given the numbers of sharks being slaughtered, and the degree to which the trade is in criminal hands, I feel that your conviction that if you only know where all the sharks are, you and your colleagues will be able to manage and protect them, is unrealistic and absurdly optimistic. One place after another, where sharks have been found to be, has been fished out.

    Even the countries that have declared themselves to be shark sanctuaries, are still battling to save their sharks, because of the problem of enforcement, and the criminal nature of the trade. Illegal trade in wildlife parts is at a peak and climbing.

    The anecdotes you cite about fishermen knowing more about where the sharks are than scientists may be true locally, there in America, at least before the scientist has done a study, but it does not apply to shark finning fleets strung across the ocean searching for sharks. Those fishermen are looking for sources of information to maximize their take, and of course they use any information available, from local lore, to diving information, to scientific announcements.

    The big companies in Asia out looking for sharks are not run by dummies.

    So, should you publish information that will be used to kill sharks? That is entirely your choice as a scientist. Just as it is the right of those who think of sharks as animals, not numbers, to protest, given the actual situation sharks are facing globally, and the devastating loss of sharks that results when you do.

  8. Melissa · July 4, 2013

    I think it is quite clear that this research is needed and that it must, without doubt, be distributed to people involved in policy development. However, I agree that the concerns about publishing real-time and unreviewed location data on publicly available platforms can be risky. In some scenarios, it is almost certainly not a problem. In other scenarios, the results could be devastating. It really is a case-by-case scenario.
    Researchers studying animal movements must be made aware of the consequences of publishing such information. In Australia we had (may still have?) a successful program that published near real-time locations of male crocodiles. These animals are generally solitary, and they are protected in Queensland. The study animals resided entirely within this state, and in an area with very few people. Therefore they were at low risk of exploitation. This is a successful program. However, I believe very few programs, especially international programs, are capable of similar success and protection.
    I’m afraid I’m not convinced by this article and the real-time publication of shark locations. As far as I am aware, sharks are gregarious animals that cross international waters and are commercially exploited. Therefore, I think there are grounds for concern, and I hope the researchers here have considered all the relevant factors. In this article, I get the sense they are justifying publication based on the need for the research, but this issue goes deeper than that – it is more about where and when the information is published. I see very few reasons for real-time data. Delays of even 1-2 weeks may make a big difference for the study subjects and their populations, but have little impact on future conservation and management actions.

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