The World’s Shark Population Has Declined 70% Since the 1970s – What Can We Do Differently?

“Sharks are beautiful,” says Venezuelan biologist and diver Elena Salim Haubold, who has dedicated her professional life to the conservation of these marine animals. Based on the Caribbean island of Sint Maarten, she facilitates encounters between sharks and tourists during the diving trips.

A new study raises the alarm that the population of oceanic sharks and rays have declined more than 70% since the 1970s. I spoke with Salim Haubold about the reasons behind that as well as the ways to change it. Our conversation has been edited and condensed for clarity.

Elena Salim Haubold with a blue shark (Prionace glauca) in Pico Island, The Azores, Portugal. 

In 2014 she traveled around the world for a year to meet and learn from the leading experts in the diving industry as European Rolex Scholar.

Ieva Zamaraitė: In 2013, scientists estimated that every year humans kill around 100 million sharks. Why is this happening and what consequences does it have for the marine ecosystem?

Elena Salim Haubold: There are more than 500 species of sharks. Populations of these species in some regions are being depleted. This means that one species might be doing well in one part of the world but declining in another. Some of the species that are in decline are critical for the marine ecosystem, since they are top predators that play a crucial role in regulating other species and communities. Sharks that qualify as top predators at their adult stage include the great white shark, tiger, bull, oceanic white tip, great hammerhead, mako, and dusky shark.

Sharks, whatever species they may be, all play a role in maintaining a healthy marine ecosystem, and without them the ocean would be a very different place. Sadly, sharks face many threats. Some species are being threatened by overfishing, which can either be due to targeted shark fishing or as a result of bycatch. The most documented and horrible example of exploitation is the shark finning industry, where sharks are caught and have their fins cut off while they are still alive before being tossed back into the ocean to drown.

Even when not targeted intentionally, sharks are also caught and killed by fishing fleets that trawl the oceans with giant nets, catching everything in their path. It is by far the most destructive fishing method because these vessels kill a huge amount of marine life and discard most of it back into the ocean, only keeping what is part of their quota.

Another threat is the pollution in the oceans, such as oil and plastics. Sometimes dead sharks are found to have a stomach full of plastic and other waste they have consumed throughout their lifetime. Harm also comes from the microplastics that they ingest from their prey because it accumulates in their bodies, possibly having detrimental effects on their health. Often, sharks and other marine life also get trapped in nets and other materials that have been discarded and dumped at sea.

Habitat degradation is also a problem and was the focus of my work at the Bimini Shark Lab in The Bahamas. My project was to research a group of juvenile lemon sharks that lived in the mangrove forest. They use these sheltered areas to hide from predators and feed on the species that are sustained by the mangroves, and their site fidelity is very high. This means that they spend most of their juvenile stage in the same area, which is essential to their development and survival. Unfortunately, during my research, a deep channel was dredged in the middle of the bay, and six of the seven lemon sharks I was tracking disappeared. More than likely, big sharks or other predators ate them because they were unable to come into the safety of the nursery area. This instance is just one small example of how human development can impact nature.

Elena Salim Haubold with a Caribbean reef shark (Carcharhinus perezi) called "Jav" in Sint Maarten.

Elena Salim Haubold at work with her dog Blacky.

What happens with mangroves also happens with coral reefs, which brings me to another point – ocean acidification, which is linked to climate change. Scientific research is revealing that higher water temperatures and CO2 levels in our oceans are having a detrimental effect on many species of marine life. We are just beginning to understand the long-term implications of this phenomenon, but a recent study has shown that ocean acidification not only degrades sharks’ habitats but also reduces their growth rate and ability to hunt effectively. Sharks rely on healthy reefs, but if the water is too warm, corals expel the algae living in their tissues, causing them to turn white and die (coral bleaching).

It is also relevant to know that sharks are vulnerable to fishing pressures because of the way they reproduce, which is very different from other fish. Sharks’ reproductive strategy has more in common with birds and mammals: they produce a few eggs or give birth only to a small number of relatively large and well-developed juveniles that have a high probability of reaching sexual maturity (see r/K selection theory).

As a biologist and a diver, you see sharks as beautiful animals that are easy to fall in love with. However, they are often portrayed in the media and movies, such as the classic Jaws, as dangerous, even killers and monsters. What is the truth, and what is the myth? And how does this image affect shark conservation?

The movie Jaws is considered a classic, but in retrospect it was devastating for sharks. I think humans have a deep-seated fear of animals and environments that we cannot conquer, and the movie Jaws sadly convinced millions of people that if you encounter a shark, it will try to eat you.

We should treat sharks the way we treat large predators on land. Most people are aware that a lion or a bear has the potential to do harm, but we study their behavior and learn to live with them because we understand they have an essential role to play in their environment. If we could start to look at sharks in that way, I think it would ultimately be beneficial to their conservation in the future.

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You practice free diving, but what do you think about diving in cages? What can you tell me about the ethics of shark diving?

Shark diving can be a controversial topic and one of the most hotly debated arguments is the practice of diving inside a cage. I think cage diving is the only safe and responsible way to dive with great white sharks. I have dived with many species of sharks, such as tiger and bull sharks, without the protection of a cage, but the great white is really in a league of its own due to the fact that it regularly hunts and preys upon large marine life, such as seals, that are comparable in size to humans.

Although they are certainly not the monsters, Jaws has made them out to be. To swim with white sharks without protection takes years of experience, and even then it is not without risk. The cages allow an average diver or tourists to come face to face with one of the ocean's apex predators in complete safety, and this activity was really the very beginning of what we now consider the shark diving industry.

Of course, there are rules and guidelines that should be followed to ensure the practice does not cause harm to the animals, and responsible operators will act based on scientific research and with both their guests and the sharks safety as a priority. This is true with any type of shark tourism, inside or outside of a cage, and any company that does not comply should be considered unethical.

A blue shark (Prionace glauca) in Pico Island, The Azores, Portugal.

A great hammerhead shark (Sphyrna mokarran) in Bimini, The Bahamas.

A Caribbean reef shark (Carcharhinus perezi) in Sint Maarten.

When practicing shark diving, the most important thing is safety – both for the sharks and divers. It is important to never allow guests to freely touch them, and trained guides must be a part of the group. It is also crucial to me that the interactions with sharks are respectful. Professionals who work with sharks on a daily basis will touch and handle sharks to a varying degree depending on where you dive and with what species, but it is certainly not something that should be attempted by anyone and, in my opinion, should be avoided as much as possible. Any negative interaction between sharks and humans is always portrayed as the shark’s fault, which annoys me a lot, so the goal should be to show sharks to people in their natural environment while disturbing them as little as possible.

It is a big responsibility to take guests who don’t have much experience to dive with sharks – you don’t want anything bad to happen to the guests or the sharks, as any accident has the potential to have a negative impact on shark conservation for years to come. There is nothing worse for sharks than the headline “Shark Attack.”

What do you think about using bait for shark diving? Does it have the ability to disturb the sharks’ natural feeding habits?

I understand why some people disagree with baited shark dives, because when I didn’t know anything about sharks, I was also against shark feeding. It required many discussions with scientists, hours of reading and research, and then just a handful of dives to change my opinion about it. The truth is that without attracting sharks in some way, it would be very difficult to get close to many of them. Of course, there are some places in the world where you see natural aggregations of particular shark species, but most of the world's famous shark dives would simply not exist without using bait.

By attracting sharks, we can bring these animals close enough to divers so we can learn more about them. Some species of sharks learn quickly how the process works. They come for a “snack,” swim around the divers, and then peacefully leave. You can condition them to come at a certain time of the day, but if they don’t want to, they won't do it. There is a lot of controversy about this so we should look into the data and the research being done about it. Although shark provisioning can change their local movements, scientific research has proven that it doesn’t affect their migration patterns or reproductive behavior.


Shark provisioning has been happening for years in many countries like South Africa, Australia, Fiji, Mexico, Portugal, and most famously in The Bahamas, where it eventually compelled the government and the local people to respect sharks and declare the entire territory as a shark sanctuary. A recent study suggests that The Bahamas is the largest shark diving economy in the world – it contributes with approximately $109 million annually to The Bahamas’ GDP. Therefore, I think that shark provisioning, when done properly, is beneficial for the sharks and their habitat.

Your interest in shark conservation stemmed from your exploration of sharks through research. But then you moved into the ecotourism industry. Why did you make that change?

One of the most important things I learned in all those years thinking about shark conservation and talking to scientists, divers, owners of dive shops, and people in governments and other organizations is that conservation has to be made profitable. But, although I left the academy behind years ago and went into shark ecotourism, I still, of course, find the science very important.

I think these two worlds should be more closely linked. Many scientists are working towards shark conservation and getting valuable information that shows, for example, the areas where a shark population is being depleted, but when they try to show it to the government or the people destroying the habitats, those governments or people usually don’t care about the data. Also, many scientists are struggling to conduct research because of a lack of funding, as some universities do not consider sharks a priority compared to other subjects. On the other side, many shark diving operators make a lot of money, but some of them don’t know much about the biology and ecology of sharks – where they migrate, where they give birth, etc. So I think there should be more collaboration between the scientists and the tour operators, and that is the goal of our dive business here in Sint Maarten. We want to learn more about the sharks we dive with on a daily basis and share this knowledge with our guests. Also, how can you know if you are helping sharks if you don’t measure the effects of what you are doing? When we go shark diving, we collect data for our studies in the future. In the long term, we want to have a scientist who works with us so we can make a valuable contribution to shark conservation in the region.

Elena Salim Haubold swimming with a group of sicklefin devil rays (Mobula tarapacana) in The Princess Alice Bank, The Azores, Portugal.

What do you see as the most effective way to protect shark populations?

One of the most important lessons I learned about protecting sharks is to not to focus on a single species, but on their entire habitat. For example, you won't make a big difference if you forbid fishermen to catch a certain shark species but still allow them to catch the fish that the sharks feed on. Sometimes it can be easy to protect sharks since they are charismatic animals. However, there are other species that people don’t care about, such as sea cucumbers, that may be just as important for the ecosystem. That is why I believe we should continue to protect patches of the ocean, called marine protected areas (MPAs), to allow the entire environment to recover. It is the best-known way to protect the oceans. Still, the problem with protecting sharks is a very complex one due to the number of species and their behaviors. For instance, reef sharks are known for high site fidelity, and so establishing an MPA will benefit them more than other migratory species that travel thousands of kilometers from one side of the world to another because each country has its own laws and rules and level of compliance.

The documentary Shark Water shows how illegal fishing was still taking place in one marine protected area in Costa Rica. How can the implementation of MPAs be made effective?

Enforcing the rules and preventing illegal activity from taking place is a huge challenge that is better managed in some places than others.

I visited Cocos Island in Costa Rica, the one from the movie Shark Water, as part of my Rolex scholarship year, and at that time, I thought that the Costa Rican government was very efficient in conservation. But soon after I arrived, I discovered that the problem was far bigger than I had imagined. I stayed on the island for a month and lived with a group of park rangers, amazing people who were very passionate about protecting nature. However, they faced many problems that prevented them from doing their job. For example, they were supposed to go out every night to check the protected area, and if they found fishermen, they had to confiscate their boat. However, in one month, they were only able to patrol for 13 nights because there was always a problem that prevented them from going out. They had three boats, two of which were damaged, and the third one always needed repairing. Plus, they often didn’t have fuel. In other words, the government didn’t provide them with the support they needed to do their job.

Elena Salim Haubold with a great hammerhead shark (Sphyrna mokarran) in Bimini, The Bahamas. In 2009 she did her bachelor thesis dissertation at the SharkLab in Bimini Biological Field Station in The Bahamas where she studied the effects of nursery habitat loss on juvenile lemon sharks. At that time she worked with her mentor Dr. Samuel H. Gruber, the founder of the SharkLab who was one of the most prominent researchers in the shark field.

Elena Salim Haubold with a tiger shark (Galeocerdo cuvier) in Tiger Beach, The Bahamas. The first time she learned that it was possible to swim with sharks was in 2007. By chance while watching TV, she saw a documentary about a diver Cristina Zenato in a chainmail suit interacting with sharks. Two years later, in The Bahamas, Cristina Zenato took Elena Salim Haubold for her first shark dive.

Later that year, I went to Fiji and saw exactly the opposite of what I found on Cocos Island. I visited Beqa Adventure Divers, a private dive company that established, and currently manages, a protected sanctuary for sharks called Shark Reef Marine Reserve. The dive masters and the captain of this company, all locals, did a course with the government to become park rangers. So, when they are at the marine protected area and see a fishermen’s boat there, they can give them a fine. Their incentive for protecting the sharks is even stronger than that of the guys from Costa Rica because, if the sharks are gone, then no tourists will come to dive with them and consequently, they will lose their jobs. I learned that ideally there needs to be a link between conservation and the financial benefit of local people.

I saw a short documentary about a man who used to traffic turtles but stopped when he got a job in a local turtle ecotourism camp. He said that it never crossed his mind that he could earn money without actually killing turtles. From your experience, how important is it to collaborate with people who are illegally fishing the sharks?

For me, at a young age, it was difficult to understand how I could be friends with fishermen or poachers. I used to see them as the enemy, but with time, I learned that instead of trying to confront them, aspiring conservationists should seek to work together with them, try to talk to them and understand what their needs are, and see if you can provide a better alternative. Using confrontation might provide a short-term solution to the problem, but once you are gone, they or other fishermen will eventually come back. In many places, like Palau and Maldives, many people who used to fish have become tour guides, which allows them to have a better job with a higher income.

Another model I really like is the shark diving industry in Playa del Carmen, Mexico, consisting of more than 40 companies. Even though those diving companies are competitors, they got together and started collecting money between themselves to give to the fishermen as compensation for not fishing the bull sharks they work with.

A tiger shark (Galeocerdo cuvier) in Tiger Beach, The Bahamas.

In general, the lesson I learned is that if you want to protect animal species, you first have to take care of the people who live in the area, understand them, and try to offer them something better that doesn’t involve killing the animal you are trying to help. My dream was to do a project in Venezuela, my homeland, where there are more than 60 species of sharks, but I couldn't, because of the current economic situation. How can I go to someone who is struggling to survive and expect them to worry or to care about sharks without being able to offer them anything in exchange? They want to put food on their tables for their families before anything else.

The tourism industry is usually sensitive to crises such as COVID-19, which has hit the whole tourism industry very hard and especially those countries that rely on tourism. How does this situation affect the project you have just started in Sint Maarten?

Nobody ever expected to be faced with the current situation, so everything is new and uncertain. Of course, the countries that rely on tourism are suffering more than anyone, and as I mentioned before, it is hard to get people to worry about the marine environment and sharks when they have so many other problems.

Our dive company is finally open for business despite the pandemic, but it has been a slow process. It's hard to believe we have been dealing with COVID-19 for such a long time, but we continue to push forward and hope for a return to some kind of normality soon. Things are slowly getting better every day, so we are trying to stay positive and continue with our plan: to have a responsible shark diving company in Sint Maarten, and at the same time, support scientific research and offer an educational experience. In other words, teaching people facts about shark ecology, behavior, reproduction, and conservation. There are still so many things to learn about sharks.

A great hammerhead shark (Sphyrna mokarran) in Bimini, The Bahamas.

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