Sharks have been on the planet for more than 400 millions years – before the dinosaurs were here, even before trees existed. They have evolved into more than 500 different species in all different sizes. While we often hear “shark” and picture “Jaws” the grey, torpedo-shaped shark is not representative of all species.
Sharks are fish – a specific type of fish called elasmobranchs, which have skeletons made from cartilage and not bone. Like other fish, they have gills that they use to filter oxygen from the water but have multiple gill slits whereas most other fish have just one. Most species of shark have muscles in their cheeks that expand and contract to move water over their gills helping them breathe. For those species that do not have these muscles, constant motion is essential to move water over their gills and keep them from suffocating.
Sharks range in size from the largest fish on Earth, the whale shark, which can grow to 18 m (61ft) to the dwarf lantern shark which can rest in your hand as an adult. Different species of shark can be found in all of the world’s oceans at varying depths. Some migrate thousands of miles to breed and feed while others have a relatively small range.
The longest living vertebrate on Earth is the Greenland shark which lives over 270 years!
Most sharks are apex predators; they are at the top of the marine food chain. Sharks have a sense we don’t, electromagnetism. With their six senses, sharks keep populations of prey species in check. Removing them in large numbers can have ripple effects that throw entire ecosystems out of balance.
To give a simple example, on reefs, sharks eat other predators, which eat plant-eaters. Without sharks, the other predators will overpopulate and overeat the plant-eaters. Without these plant-eaters, plants will grow out of control and suffocate coral reefs. In this way, sharks directly or indirectly affect all levels of the food chain and maintain balance in the entire ecosystem.
Another example: sharks tend to eat weak and sick animals that are easy prey. This keeps disease rates low and helps to stop the spread of disease which keeps their prey species healthier. In addition, like other apex predators, sharks eat many different species. When one species becomes harder to find, sharks switch and eat another. In this way, they maintain a balance, not allowing any species to overpopulate but not depleting any either.
It’s not just marine species that sharks protect, they help all of us by making oceans fight climate change. Tiger sharks swim in shallow seagrass meadows, keeping sea turtle and dugong populations in check and thus avoiding overgrazing. This maintains the health of seagrass ecosystems which capture 35x more carbon than tropical rainforests.
For these reasons and so many more, these apex predators are essential to keep the largest ecosystem on Earth, the ocean, healthy.
Sharks are often portrayed as a threat to humans. But while sharks might kill an average of 6 humans each year, in that same year, humans kill an average of 100 million sharks. That’s 2-3 sharks killed per second. Today ⅓ of shark species are threatened or endangered due to human activity. There has been a 70% decline in shark populations in the last century; for some species, more than 90%.
While bycatch, entanglement, and habitat loss pose threats to shark populations, nothing causes as much damage to sharks as overfishing. Countries all over the world participate in shark fishing with the top four (responsible for 35% of the annual catch) being: Indonesia, India, Spain, and Taiwan. The remainder of the top 20 shark fishing nations are responsible for another 45%: Argentina, Mexico, Pakistan, USA, Japan, Malaysia, Thailand, France, Brazil, Sri Lanka, New Zealand, Portugal, Nigeria, Iran, the UK, and South Korea. Sharks are sought for fins, meat, leather, liver oil and cartilage as well as jaws and teeth. While fins may be the main driver for the shark fishing industry, it is by no means the only one. Shark meat is in high demand, particularly, but not only, in Europe.
Shark Finning
Adding to the overfishing problem, with shark fins in high demand, the cruel practice of shark finning is widespread in order to increase the catch and save room on the boat. Shark finning involves slicing the fins off the shark while the animal is still alive. The shark is then thrown back into the sea to suffocate, bleed to death, or starve. This saves space on the boat as only fins are kept and not the entire body.
This practice is illegal in many areas, but current controls on shark fishing and shark finning are insufficient; there are not enough regulations and enforcement is lacking. This wasteful practice provides high value fins for shark fin soup in Hong Kong and China. This soup is served at special occasions as a luxury item in Chinese culture. Sadly, the fin provides no taste but only texture (and status) to the soup.
Reproductive Strategy
One reason shark species are threatened is that they are very slow breeders, taking years to reach reproductive age. Additionally, many species produce very few pups in a litter, and may take a year or more between litters. This is a sharp contrast to bony fish that may release hundreds of eggs at a time and can spawn annually or more frequently. Sharks are very susceptible to overexploitation and fishers are not giving shark species enough time to reproduce and recover.
Habitat Loss
Coastal development is also contributing to the reproductive problems of shark populations. Some species of shark rely on mangrove ecosystems and coral reefs for breeding, nursing young, and hunting. As these ecosystems disappear, so do shark populations.
First and foremost, spread awareness about sharks and their valuable contributions to the marine ecosystem. The media and entertainment industries have trained people to fear sharks which allows a level of indifference to how they are treated. This cannot continue. Humans are a much bigger threat to sharks than sharks are to humans. And only by realizing that can we begin to make real changes and protect these essential animals.
Demand an End to Shark Finning
This practice is cruel, wasteful, and unethical. Fished sharks must be returned to land with their fins attached. This not only allows limits to be enforced, but also ensures that the entire animal is used and not carelessly discarded. Complete bans on the removal of shark fins at sea, without exceptions, must be enacted regionally and nationally. It is only by treating these species’ with respect that we can ensure their long-term survival.
Lobby for Greater Shark Protection
Public perception and public pressure have a great deal of power, especially in the age of social media. Corresponding with lawmakers, news editors, and publically on social media and through tourism channels, can make a difference. Vocal support for shark conservation from the public is essential to ensure these animals are protected. Your voice matters. Support shark fishing regulations and the creation of marine protected areas that can benefit shark species.
Don’t Buy Shark Products
Don’t buy shark souvenirs. In tropical coastal areas, shark teeth and shark jaws are popular souvenir items. A shark likely died for that souvenir.
Many cosmetics include squalane, which comes from shark liver oil. Squalane is popular as a base for moisturizers, deodorant, lipstick, and other cosmetics because it is non-greasy. Consider the impact of non-oily cosmetics on the ocean and the planet before you buy.
Don’t Eat Shark Meat
Do not eat shark fin soup and do not patronize restaurants that serve it. Avoid shark steaks. Mako, thresher, and blacktip shark steaks are popular in the US. But, avoiding shark meat isn’t always simple. Be aware that shark meat is much more prevalent that you may realize. It is not always called “shark” on a menu or at the market. Since sharks are fish, shark meat is often generically marketed as “fish” and used in frozen fish fingers. Fish and chips often includes shark meat in the UK and Australia. In Germany shark is smoked and sold as “Schillerlocke.” Hakarl, a delicacy in Iceland and Greenland, is made from Greenland and Basking shark. Ask what meat you are buying or eating.
Support Shark Tourism
Many regions of the world have managed to curtail shark fishing by putting a higher value on live sharks: the tourist dollar. Plan vacations around shark-tourism. Snorkel or dive with sharks to support this alternative to fishing. Choose responsible, locally owned operators who employ local staff to ensure that the community benefits from keeping these animals alive. Make sure your guides follow procedures and local codes of conduct intended to protect the animals.
Support Shark Conservation Organizations
There are so many organizations acting as the voice of shark species. They need your support. Many of these groups are very involved in lobbying governments and regulatory bodies. They often have petitions and seek public input — use your voice and spread the word.
We must all act together to save the apex predators that a healthy ocean needs.
Many organizations do amazing work to educate people about the importance of sharks and the threats to them and their habitats. Learn more about some of these organizations, their work, and what you can do:
Gili Shark Conservation
OceanCare
Project AWARE
SeaKeepers
Shark Guardian
Happily there are many successes in shark conservation. Sadly, many many more are needed to save these amazing animals. Here are a few that inspire me.
Tubbataha Reef, Philippines
During a recent research expedition, the Tubbataha Reefs Natural Park was found to host an incredibly high number and variety of reef sharks. A protected area since 1993, Tubbataha has given shark species time to recover. The park is remote and rules are enforced, again proving that nature can restore itself if humanity gives it a chance.
From Shark Fishing to Shark Tourism – Isla Mujeres, Mexico
In 2008, off the coast of Isla Mujeres, Shawn Heinrichs heard about large numbers of whale sharks in waters near this fishing village. In 2009 he returned to find over 300 whale sharks feeding together. Mexico designated the Whale Shark Biosphere Reserve to protect them. Fishermen were no longer able to fish for sharks. Now, fishermen are employed as captains and guides instead of fishing, making a much better living.
UK Shark Fin Ban
In May 2021, the UK Government launched their Action Plan For Animal Welfare including a ban on the import and export of detached shark fins to “protect the iconic shark species.”
Misool Marine Reserve, Raja Ampat, Indonesia
The Misool Marine Reserve began in 2005 as a partnership between the local communities and a private resort owned by passionate conservationists. The Reserve leased the area, which was once home to a shark fishing camp, and designated it as a no-take zone (no fishing, collecting eggs, or shark finning), the first in the region. The area has seen an increase in fish by an average of 250% (some sites surpass 600%), 25 times more sharks than outside of the reserve, and 25 times more manta sightings. The ocean can heal itself if left alone!