Endangered Sharks: A Crisis in Our Oceans

Endangered Sharks: a crisis in our oceans

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Sharks are feared by humans, but there are many more threats to them than they pose to us. There are more than 1000 species of sharks and rays, but as many as a third of these are currently facing extinction. That’s around 300 species that could soon be lost to our oceans.

While sharks might have a bad reputation, they’re actually integral to the ecosystem. They improve biodiversity and, being apex predators, are essential in keeping other populations in check.

Why Are So Many Sharks Endangered?

As much as it pains me to admit, it’s humans that are the main cause of endangerment in sharks. With things like habitat destruction, pollution, and overfishing, we only have ourselves to blame for their declining numbers.

Overfishing

Why are so many sharks endangered: overfishing

In some places, shark is a favorite meat of humans and is used to make things like shark fin soup. While this is considered a delicacy with medicinal properties in China, it’s now become a popular dish in high-end western restaurants so the demand for shark meat has increased.

What’s even more concerning is that DNA tests have shown that there is shark meat present in foods that we don’t expect, such as fish and chip shops in the United Kingdom. And it’s being taken one step further with many pet food products also containing ‘ocean fish’ the ingredients of which are sometimes endangered shark species.

In countries like Costa Rica, more than 7000 hammerhead sharks are fished and brought ashore every year, despite two out of the three species being critically endangered.

But they’re not only fished for their fins and meat, sharks are also targeted for the oils they produce as well as for their cartilage. Squalene is the name for the oil produced in a shark’s liver, and it’s popular for its antioxidant properties. Around 90% of squalene use can be attributed to the cosmetic industry, but many people aren’t even aware that this is what is in their skincare products.

Worryingly, more than 100 million sharks are fished annually, meaning that around one third of all species are now at risk! And this doesn’t account for the pirate fishing that takes place around the world.

Even where commercial fishermen are catching other species, sharks are often accidentally caught in the nets. While they may be released, it’s not uncommon for them to become so tangled that they end up being strangled to death.

What’s more, baited drum lines are set up along coastal areas to prevent sharks from entering swimming waters. However, although these lines are supposed to be ethical, there’s more than enough evidence to show that sharks are being killed as a result of them.

Potentially the saddest reason for overfishing is shark culling. This is done for several reasons, but in many cases, it’s out of pure hatred for these creatures. In many situations, people perform shark culls in the belief that they are protecting their fishing equipment for local people, when in reality, all they are doing is decreasing shark populations so much that they’re driving them to extinction.

Climate Change

Why are so many sharks endangered: climate change

Our oceans play an integral role in the reversal of climate change by capturing carbon that would otherwise be in the atmosphere. However, it’s something of an ironic situation since the inhabitants of the oceans are already being affected by climate, and it’s not looking good.

There are several issues that affect ocean dwellers because of climate change, including alterations in the water chemistry, rising temperatures, and erosion. One of the ways that many fish are dealing with rising temperatures is by moving further from the equator. While sharks will need to follow suit in order to have access to enough food, they evolve much more slowly which means they may not be able to handle conditions as readily as other species.

According to projections, it’s thought that sharks may have to move as many as 40 miles (64 km) per decade towards the poles. This takes them away from waters that are warming and into cooler conditions. Not only this, but sharks’ migratory patterns are also being affected by climate change.

Habitat Destruction

Why are so many sharks endangered: habitat destruction

With more than 1000 shark and ray species, it won’t come as a surprise that they can be found in a variety of different ocean habitats. However, one of the major threats to these creatures is the rapid destruction of their natural habitat, forcing them out.

A lot of shark species move into estuaries when raising their young, but with these areas being destroyed or removed for things like housing, they’re faced with having to go elsewhere. Similar issues are happening in breeding grounds, such as coral reefs which are becoming less diverse due to phytoplankton dying off in acidic waters. The coral reef feeds on this phytoplankton which other species feed off the coral. Without the plankton, the entire food chain is affected. The result of this is less food for sharks.

On the island of Bimini in the Bahamas, mangroves are being destroyed which spells bad news for the lemon shark. Much of the damage to their habitat can be attributed to the local fishing methods, which are damaging things like corals and sponges.

Marine Pollution

Why are so many sharks endangered: pollution

Our oceans are being polluted just as much as our atmosphere and this is having a devastating effect on shark populations. There are two large garbage islands in the Pacific and Indian oceans, with an area larger than the state of Texas. As the rubbish in these islands degrades, the resulting chemicals are being released into the ocean and poisoning sharks and other species. What’s more, studies have shown that there are traces of various chemicals in sharks, such as the angel shark in Brazil. Toxins such as methyl-mercury are being found in sharks, and not only is this dangerous for the individual, but it can also affect the shark’s ability to breed, further decreasing the population.

What is the Importance of Sharks?

Importance of sharks

While many of us probably don’t spend a lot of time thinking about the importance of sharks, there’s no denying that they are vital to marine ecosystems.

Tourism

Many places in the world rely on tourism to thrive, and where there are shark infested waters, there’s an instant tourist attraction. People flock to these areas for a chance to get up close and personal with nature’s toothed predators through cage dives and SCUBA. In some parts of Australia, shark tourism brings in $17.7 million of regional profit, and across the entire United States, shark tourism accounts for $300 million annually!

Medical Research

Did you know that sharks could hold the key to controlling or curing medical conditions such as cystic fibrosis? These large fish have been noted not to become sick as often as other species and scientists believe that this is because of the antibacterial and anticoagulant properties of the shark’s tissues.

Research is now being performed to see how we might use this in medicine, and there are also studies taking place to see how shark skin could be used to ward off bacteria and pathogens in medical settings.

Controlling Ocean Populations

Sharks are apex predators meaning that nothing eats them; they’re at the top of the food chain. While that might be a scary thought, these creatures are incredibly important in keeping other ocean populations under control. Without sharks feeding on smaller species, there would be a population boom that wouldn’t be healthy for the oceans.

Ocean Health

The ocean holds a lot of carbon, and this is important for climate change but also the health of the ocean. Sharks help to keep carbon levels in check as they hold massive amounts of this compound in their bodies. When they die and sink to the bottom of the ocean becoming food for scavengers.

Endangered Shark Species

With more than a third of shark species facing some sort of threat, it can help to further understand the issues that these species are battling. Below, I’ll discuss some of the worst-affected shark species and what’s causing their endangerment.

1. Great White Shark (Carcharodon carcharias)

Great white sharks (Carcharodon carcharias) are now considered to be vulnerable and much of this is as a result of fishing.

The great white shark is one of the most easily recognisable shark species and also one of the largest. Measuring up to 16 feet (4.9 meters), these are huge creatures, and the largest recorded specimen weighed more than 4,400 lbs (1,995 kg)!

Great white sharks are found in all of the world’s oceans and tend to stay around coastal areas, although they will go into the open ocean and have been found at depths of up to 3937 feet (1200 meters).

These giants are now considered to be vulnerable and much of this is as a result of fishing. It is suggested that they’re now more threatened than tigers with one scientist claiming there are only around 3500 left in the wild.

2. Great Hammerhead (Sphyrna mokarran)

According to the IUCN red List, the great hammerhead is considered to be critically endangered.

According to the IUCN red List, the great hammerhead is considered to be critically endangered. Out of all the hammerhead species, the great hammerhead is the largest and can grow up to 15 feet (4.6 meters) in length.

The shark takes its name from the hammer shape of its head, and these fish are usually found in tropical waters no more than 40 degrees north or 37 degrees south.

The main threat to the species is fishing and in places like Mexico, it is a victim of bycatch. As such, it’s thought that numbers have halved since the 1990s.

3. Scalloped Hammerhead (Sphyrna lewini)

The main threat to the scalloped hammerhead is overfishing, particularly illegal fishing and bycatch.

Another hammerhead species that is at risk is the scalloped hammerhead which is also considered to be critically endangered. It first received this status in 2018, and numbers continue to decline; it’s thought that there are as few as 200 left in the oceans.

Smaller than their great cousins, scalloped hammerheads only grow to around six feet (1.8 meters) and are often found around coasts in both temperate and tropical waters. As is the case for many shark species, the main threat to the scalloped hammerhead is overfishing, particularly illegal fishing and bycatch.

4. Pondicherry Shark (Carcharhinus hemiodon)

Pondicherry sharks (Carcharhinus hemiodon) are so rare these days that the last recorded sighting occurred in the 1970s.
Zoological Survey of India / Wikimedia Commons / CC BY-SA 3.0

A small shark that grows no more than 3 feet (1 meter) in length, the Pondicherry shark is found in the Indian Ocean. While once common off the coasts of India, numbers have declined so much that these sharks are now a rare sight. Being critically endangered, it is estimated that there are fewer than 250 left in the wild.

These sharks are so rare these days that the last recorded sighting occurred in the 1970s. There was a suspected sighting in Sri Lanka in 2019, but this was not confirmed.

5. Pelagic Thresher (Alopias pelagicus)

Populations of pelagic thresher (Alopias pelagicus) sharks are in decline.

Pelagic threshers are mid-sized sharks that usually measure around 10 feet (3 meters) in length. There are three species of thresher shark, and the pelagic is the largest of the three. They’re found typically in Indo-Pacific regions, although they are often confused with the common thresher, so it can be difficult to determine their true distribution.

In terms of numbers, it’s thought that populations are in decline, although there is no information on exactly how many individuals are left. That said, the situation is concerning enough that the species is listed as critically endangered.

6. Dusky Shark (Carcharhinus obscurus)

One of the main threats to the dusky shark is overfishing, and humans are sourcing them for their livers and skins.

The dusky shark is found all over the world, although it is more common in tropical or warm temperature waters. Females can have a litter of up to 14 young, and while this does seem like a high number, it’s seemingly not enough to boost the population and the dusky shark is now listed as endangered, with numbers still declining.

One of the main threats to the dusky shark is overfishing, and humans are sourcing them for their livers and skins. On top of this, they’re often the bycatch of tuna fisheries.

7. Oceanic Whitetip Shark (Carcharhinus longimanus)

Oceanic whitetip sharks (Carcharhinus longimanus) are now critically endangered as a result of overfishing.

The oceanic whitetip shark is another fish that produces a lot of young, with up to 15 pups in a litter. Much like many other sharks, this species is typically found in coastal areas, but it’s not unusual to see them in the open ocean. They prefer warmer temperate waters and tropical regions.

Oceanic whitetip sharks are now critically endangered as a result of overfishing. But it wasn’t that long ago, in the late 60s, that these sharks were described as one of the most abundant. Since then, reports have shown that there has been a decrease in numbers of up to 70%.

8. Whale Shark (Rhincodon typus)

Whale sharks are now considered to be endangered according to the IUCN Red List, and it’s thought that there are somewhere between 100,000 and 200,000 left in the wild.

The whale shark is the largest type of shark, and the largest type of fish currently on record. While they typically grow to around 40 feet (12 meters), the largest specimen was reported to be more than 61 feet (18.6 meters) in length. Not only are they massive, but whale sharks also have incredible longevity and may live up to 130 years.

Whale sharks are now considered to be endangered according to the IUCN Red List, and it’s thought that there are somewhere between 100,000 and 200,000 left in the wild.

9. Basking Shark (Cetorhinus maximus)

Basking sharks are the second largest species of shark after the whale shark and are also considered to be endangered with numbers still on the decline.

The basking shark is probably most well-known for its unique appearance since they have large, gaping mouths which they keep open during feeding. However, contrary to popular belief, they don’t swim around like this all of the time.

Basking sharks are the second largest species of shark after the whale shark and are also considered to be endangered with numbers still on the decline. The populations that are left are found in temperate and boreal waters, usually in coastal regions.

10. Daggernose Shark (Isogomphodon oxyrhynchus)

The main threat to Daggernose sharks is artisanal fishing for Spanish mackerel where the sharks are caught as a bycatch.
Naturalis Biodiversity Center / Wikimedia Commons / CC0

The daggernose shark is considered to be critically endangered across its entire range. However, this has never been a very widespread fish and is typically found in mangroves and estuaries around the northeastern parts of South America. The main threat to these sharks is artisanal fishing for Spanish mackerel where the sharks are caught as a bycatch.

These fish also have a unique appearance with a long dagger-like snout, as their name would suggest. They can live up to 20 years but are not large sharks and don’t usually exceed 5 feet (1.5 meters) in length.

11. Caribbean Reef Shark (Carcharhinus perezi)

Caribbean reef shark numbers are still in rapid decline, and while some of this can be attributed to overfishing, they are also victims of habitat loss of the coral reefs in which they live.

Occurring in the tropical parts of the western Atlantic, the Caribbean reef shark is now considered endangered on the IUCN Red List. They are generally found in shallow waters and are often mistaken for several other species, including the dusky shark and the blacktip shark, among others.

Caribbean reef shark numbers are still in rapid decline, and while some of this can be attributed to overfishing, they are also victims of habitat loss of the coral reefs in which they live. However, efforts are being made to protect them, and in US waters, it is now illegal to fish them.

12. Sand Tiger Shark (Carcharias taurus)

As of 2020, the sand tiger shark has been listed as critically endangered.

One of the most distinctive features of the sand tiger shark is its small eyes which are totally lidless. They’re a relatively widespread species of shark and can be found in North and South American waters as well as around the coasts of South Africa, Japan, and Australia. As their name suggests, sand tiger sharks frequent sandy shorelines.

As of 2020, the sand tiger shark has been listed as critically endangered. There are a number of things that have led to their continuing decline, including being a target for fishermen because of their skin as well as the fact that these sharks reproduce at a very slow rate.

13. Bonnethead Shark (Sphyrna tiburo)

In 2019, the bonnethead shark was listed as endangered and it’s thought that numbers are still declining although there is a species recovery rate of around 44%.

In 2019, the bonnethead shark was listed as endangered and it’s thought that numbers are still declining although there is a species recovery rate of around 44%. In recent years, numbers have decreased by as much as 79% around the world and up to 80% within the last three generations alone.

Bonnethead sharks have a flat head which is where they get their name and are usually found around the coasts of America on both sides of the country. The species prefers coastal areas with sandy or seagrass floors as well as estuaries.

14. Pacific Nurse Shark (Ginglymostoma unami)

The Pacific nurse shark was listed as endangered in 2019 on the IUCN Red List.

Pacific nurse sharks are opportunistic fish that often hunt along the seabed for bottom-dwelling fish. They are most commonly found from Baja down to Mexico and Costa Rica and are medium sharks that only grow to around 9 feet (2.7 meters) in length.

The Pacific nurse shark was listed as endangered in 2019 on the IUCN Red List.

15. Ganges Shark (Glyphis gangeticus)

One of six species from the same river shark family, which includes the bull shark, the Ganges shark is now critically endangered, and it’s thought that there are only around 240 left in the wild.
Müller & Henle / Wikimedia Commons / Public Domain

Sometimes confused with the bull shark, the Ganges shark is a species that is found exclusively in the Ganges River in India as well as the Brahmaputra River that runs through India and Bangladesh. Many of the shark’s feeding habits are still largely unknown, but it’s thought that they mainly feed on fish.

One of six species from the same river shark family, which includes the bull shark, the Ganges shark is now critically endangered, and it’s thought that there are only around 240 left in the wild.

16. Zebra Shark (Stegostoma tigrinum)

The zebra shark, found in tropical Indo-Pacific waters, is listed as endangered.

The zebra shark, found in tropical Indo-Pacific waters, is listed as endangered. However, there seems to be a ray of hope for this species since researchers from Swansea University have discovered a potential new breeding hotspot which has resulted in a push for the protection of this habitat off the coast of Africa.

These sharks are one of the more docile species, and it’s not uncommon for humans to be able to approach them in the water for interaction. However, the most common and upsetting interaction with humans comes in the form of fishing, where the zebra shark is targeted for its meat and liver oil. Although some countries, like Australia, have put a stop to fishing for this species.

17. Blue Shark (Prionace glauca)

The blue shark is considered near threatened.

The blue shark is fortunately not as under threat as some of the other species I have discussed, but it’s still considered near threatened. While it isn’t known exactly how many are left in the wild, it is thought that numbers are continuing to decline.

The main reason for this is overfishing, and it’s thought that the blue shark makes up 60% of all shark catches combined.

Sometimes called the great blue shark because of its relatively large size, this species is normally found in cooler waters. One of the most amazing things about the blue shark is its lengthy migration from the northern parts of North America down to South America. However, where it is found in warmer waters, the blue shark will normally retreat to deeper parts of the ocean.

Protecting Endangered Sharks: What’s Being Done?

What's being done to protect endangered sharks?

While many shark species are currently under threat, there are things we can do to help them recover and protect those that are left in the ocean.

Sustainable Fishing Practices & Regulations

There are some countries that have already taken action to protect sharks from overfishing. For example, in the United Arab Emirates, a ban has been placed on the import and export of shark meat in an effort for conservation.

In the United Kingdom, an invention has been created which is designed to emit electrical impulses from fishing nets to scare sharks away and prevent them from becoming a bycatch.

Changes to the type of fishing gear we use, such as the net attachment described above, can be effective in protecting sharks. For example, certain fishing lines can be impossible for sharks to bite through so, in Fiji, fisheries have replaced these lines with monofilaments that the sharks can chew through to escape in the event that they get caught. Similar measures are being taken in the US and Canada, where harmful fishing equipment is being banned.

But there’s still more that can be done including putting limits on the fishing of certain shark species. Under global trade rules, more and more shark species are being added to a list of protected species in an effort to quell their capture for their meat and fins. The latest addition was the raft shark and more than 200 countries have gotten on board with protecting it.

International trade of sharks is regulated by The Convention on International Trade in Endangered Species or CITES, and in the latest efforts, more than 75 shark species are being added to the protected appendix. Moreover, there are some countries, such as Palau, that are creating shark sanctuaries; areas where shark fishing is prohibited. After Palau created the first sanctuary, several other Pacific nations followed suit.

Marine Protected Areas

With many shark species native to Pacific waters, more and more countries in these areas are getting on board in creating protected areas for these fish to thrive. Samoa has recently created a shark sanctuary that covers more than 49,421 sq miles (128,000 sq km), which brings the total Pacific marine protected areas to more than 17 million sq miles (44 million sq km).

In recent years, more focus has been placed on creating Important Shark and Ray Areas or ISRA. These are areas of habitat that support more than one shark species, and while they are not governed in the same way as Marine Protected Areas, the criteria for them is being used to shape decisions and learn more about the vulnerability of sharks.

The sad news is that, at the current time, while there are a lot of MPAs, the size of them simply isn’t large enough to offer sharks the protection they deserve. However, with more areas being added, like the protection now offered around South Africa to protect the mako shark from fishing, there is hope for the future.

Shark Fin Trade Regulation

One of the biggest reasons for shark fishing is for their fins, but this is also one of the main causes of their endangerment. At the latest CoP meeting, more than 100 species of shark were added to the protected list to ensure that the global fin trade is sustainable.

The very act of shark finning is disturbing and abhorrent. In many cases, the sharks are fished before having their fins and tails removed and are then disposed of in the ocean to meet a painful and distressing demise. However, with the requirements of MSC fisheries being enforced, this is a practice that will come to an end. Fisheries suspected of finning will be suspended, and as many as 21 countries have now banned finning in its entirety.

Education

I think a lot of people would admit that they don’t know enough about the issues faced by sharks, and this often leaves people blissfully unaware. This is why education is so important especially when it comes to talking about why sharks are not a danger to humans.

Yes, there are shark attacks, but these animals kill less people annually than things like hippos, crocodiles, snakes, and even mosquitoes. In most cases, shark attacks on humans are a result of mistaken identity.

It’s also important to teach people about how humans are impacting shark populations and what will happen should these creatures become extinct. With a greater understanding of things like plastic in the ocean and overfishing, the public will be more easily able to play a role in reversing the damage.

In some parts of the world, people’s livelihoods rely on things like fishing, but this is causing serious damage to the shark population, whether intentional or not. It’s vital that we work with these communities to find safe ways of commercial fishing or alternative ways of living where sharks are not put at risk.

A lot of people are not aware of the choices they make regarding seafood consumption and items containing shark products, such as skin care. Learning more about this is an incentive for people to make better, more educated choices leading to a decreased demand for shark products.

Sustainable Tourism

Shark tourism is big business in several countries around the world and it’s really important that eco-tourism remains a priority. Studies in the Philippines have shown that those taking part learned enough about sharks to positively change their opinions on these fish. Moreover, eco-tourism is a viable way for locals to earn an income and can help to support conservation efforts.

Sadly, there is still a lot of work to do where tourism is concerned since many attractions are being managed in a way that is detrimental to the sharks. For example, chumming is one way that organizers will attract sharks to an area for tourism. However, this practice is known to negatively impact the local habitat thanks to decaying meat and fish that is left behind. This can decrease the health of coral reefs and affect the balance of the ecosystem.

Restoring Shark Habitats

Shark habitats are being spoiled by various factors, but by restoring them and giving these magnificent creatures places to feed and breed, we may see a rise in their numbers. There are currently efforts to restore mangroves and coral reefs and this has started with replacing lost vegetation in areas like Pangatalan Island, where more than 12,000 mangrove trees have been replanted since 2011.

The Coral Triangle in the western Pacific is home to more marine species in terms of concentration than anywhere else in the world. But the habitat here is in need of restoration and as such, three new projects are now underway including the addition of artificial reefs.

In Australia, seagrasses in Shark Bay were significantly damaged by a heatwave back in 2011. However, restoration efforts are now in place to aid the natural recovery of these seagrasses and improve local shark habitats.

But it’s not just about what we can do to repair the damage that has already happened, it’s vital that we take action to prevent damage in the future. Things like reducing plastic pollution are incredibly important.

Researching & Monitoring Shark Populations

Understanding more about sharks and their global populations gives us a clearer picture on what we need to do to protect them. While numbers are rapidly declining in the present day, it appears that shark populations haven’t been stable for some 250,000 years! Recent genome sequencing in mako and hammerhead sharks has demonstrated this decline over the last quarter of a million years.

Further studies are being undertaken by Canadian researchers who are using tags and receivers to track the habits of sharks on a global scale. They hope that by gathering this information, they’ll better be able to manage and sustain aquatic life in the future regardless of the changing environment. Similar electrical monitoring is taking place in Alaska.

What’s even more encouraging is that shark researchers from around the world are coming together to share information and ideas as part of the Global Shark Movement

With more than 40 teams from 26 countries, the idea is to study sharks to find ways to manage threatened species and improve biodiversity in the ocean.

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