Sharks – ruthless killers or just misunderstood?

Sharks – ruthless killers or just misunderstood?

Defining Sharks

Sharks! We all know what they are. However are sharks ruthless killers or just misunderstood? Many movies have been shown portraying them as evil, blood hunger creatures, such as Jaws. However, those types of films did any favours for the general shark population. Now don’t get me wrong, I’m not saying that shark attacks on humans are right; however, they have been stereotyped in the incorrect light, and I think we need to hear the shark’s side of the story as well.

Sharks - ruthless killers or just misunderstood creatures?
Hammerhead sharks usually swim in groups known as a school.

Sharks are one of the most evolutionary different fish lineages and play critical functional roles in marine environments. Sharks have evolved in a diversity of marine habitats, withstanding extreme ecological change and five mass extinction events.  Although most often associated with marine habitats, some species occupy brackish and even freshwater habitats, and in many systems shark species are considered meso – or apex-predators. As apex predators, sharks are critical to ocean health by keeping ecosystems stable. They remove the sick and weak from the marine ecosystem, keep fish populations in check, prey on invasive species and help coral reefs thrive. Fish-hunting sharks weed out weak and sick individuals, ensuring that the fish population remains healthy and at a size that the habitat’s resources can support. These predators can even help to preserve their ecosystems through their presence alone, tiger sharks Galeocerdo cuvier that live in seagrass meadows scare away turtles and keep them from overgrazing the vegetation.

Sharks also play a role in regulating oxygen production in the ocean, by feeding on fish that devour oxygen-generating plankton. Coral reef environments are another excellent example of sharks’ importance for overall biodiversity and ecosystem health. If the sharks disappear, the smaller fish explode in population, because nothing’s eating them, their food – plankton, microorganisms, little shrimps – all of that will be eaten, so all the little fish ultimately starve.”

When that happens, algae and bacteria move into the reef, covering the coral so that it can’t photosynthesise. “The coral will die, leaving just its skeleton behind, which eventually turns into limestone. Then, in come the animals like starfishes and sea urchins; we call those grazers. So instead of a bunch of different species — sharks, bony fishes, invertebrates and molluscs — you end up with a reef with four to five species in it, tops. That’s a dead reef. 

Sharks serve another critical role in ocean food webs: They are food for marine carnivores. Dead great white sharks that washed up on South African beaches without their livers were thought to have been victims of orca attacks. And video footage recently showed a dogfish shark (Squalus clarkae) feeding frenzy on the bottom of the Atlantic that ended with a grouper swallowing one of the sharks whole. Even octopuses are known to feed on sharks.

Shark Attacks

Human-wildlife conflicts result from the negative impacts of interactions between wild animals and people. Mitigating human-wildlife conflicts is a growing challenge, particularly since the overlap between wildlife and humans is increasing. Over the past three decades, the number of unprovoked shark bites on humans has grown around the world. This increasing trend has been documented in multiple countries and has been anecdotally linked to increasing recreational activities, particularly surfing.

Sharks - ruthless killers or just misunderstood creatures?
A lucky survivour shows his surf board where the shark bit into his surf board.

 The vision of white sharks is very acute, and even the smallest objects on the surface are detectable from relatively large depths. The theory of mistaken identity has been proposed to explain why sharks likely bite surfers. It states that a surfer resembles a seal when seen from below and therefore might accidentally get bitten. Although questioned in the past, this theory has never been adequately tested and, until proven correct, should merely be seen as an assumption and not be used factually. Shark bites on humans have been documented throughout history: La Réunion, a French volcanic island located in the tropical Southwest Indian Ocean. From 2010 to 2017, 23 shark bites occurred around La Réunion, including nine fatal events. This situation had a dramatic impact on ocean-based recreational activities and has created what the media described as a “shark crisis” involving ocean-users, scientists, and management authorities. A suite of environmental variables was selected to represent the environmental conditions given the presence of shark bite events on surfers; these include depth, moon cycles, cumulative rainfall, cloud cover, water turbidity and wave height. Although most of these interactions result in minor injuries akin to that of a dog bite, only about six of the 75–100 unprovoked attacks that currently occur worldwide each year result in human mortality. Despite its relative rarity, shark attack is a cultural phenomenon that draws intense public interest in the popular media with myths and misconceptions routinely perpetuated on television, in magazines and newspapers and social media. Three shark species that attract much of that attention are the bull shark Carcharhinusleucas, tiger shark Galeocerdocuvier, and white shark Carcharodoncarcharias. These species are of interest to biologists because they are large, migratory species of cosmopolitan distribution; however, they are also widely-known species in the public sphere owing to their depiction in movies, charismatic megafauna status, and for their association with reports of fatal shark attacks. According to the yearly worldwide shark attack summary only 130 shark attacks were reported.

A shark attack surviour being rushed to hospital.

Shark fin soup

“It’s bizarre and tastes more like glass noodles. It is in a great broth, but you can have anything in there, chicken or pork belly. The only thing that’s spoiling the dish is the shark fin”. This was Gordan Ramsey’s response (a 3 Michelin star chef) when he tried shark fin soup for the first time. He made a documentary about shark fin soup a couple of years ago, highlighting the trade in regards to the sheer amounts of shark fin which is traded, the level of ease it is to acquire a shark fin and eat it in a restaurant. He also showed the brutality of cutting the sharks fin off on the boat and throwing it back into the water where it will die.

Sharks have become commercially valuable for their fins, meat, liver oil, gill rakers, leather. Shark was once considered the less valued bycatch of more profitable fisheries stocks, such as tuna and cod. The rising demand for products, coupled with the decline of valuable fisheries, however resulted in rising catches and retention of shark and ray species. Shark fishing is often described as a relatively recent phenomenon, driven by a lucrative and booming market for shark fin that flourished with the expanding Asian upper classes during the last 30 years. Yet humans have eaten sharks for thousands of years, and coastal communities have fished them since ancient times. In China, shark fins have been traded as a commodity since the Sung Dynasty to make a prestigious soup historically reserved for royalty.

Sharks - ruthless killers or just misunderstood creatures?
Sharkfin soup.

China’s massive economic growth in the 1980s brought with it an attitude of ‘to get rich is glorious’ that resulted in a surge in demand for shark fin, regarded as a fruit of prosperity. This transformed artisanal shark fisheries in source countries into commercial fishing and gave rise to the contentious practice of shark finning, where a shark’s carcass is dumped back into the sea after its fins have been cut off. I don’t think we would be too impressed if a shark came out the water, into our home with a sharp knife, cut our leg off and then swim back into the ocean as if nothing happened. Today, fishing sharks for their fins is the primary driver of global declines in their populations. Indonesia ranks as the world’s largest shark producer, with a reported average annual production of over 106,000 t or 13% of world shark captures. During the same period, global imports of shark fin to trade centres in China averaged an annual volume of 16,815 t with a value of (US$377.9, £308.5, R5719.3 million per year).

Sharks - ruthless killers or just misunderstood creatures?
Sharks fins drying out on top of a building.

Luckily reports suggest that shark fin prices and import volumes to Hong Kong dropped steeply in 2012 for which several reasons have been proposed. These include campaigns aimed at reducing demand by raising awareness of the effects of finning on diminishing shark populations social dissent prompting a ban on shark fin soup at official banquets concerns about food safety and fake shark fins leading to reduced demand changes in custom commodity codes (where shark fins are labelled as shark meat) that disguise continued trade and diminishing supplies following global declines in shark stocks.

The United States Congress is currently considering a nationwide ban on buying or selling shark fins, which are consumed as part of shark fin soup. Such a nationwide ban would build on a movement that began in a few states including California, New York, and Texas, and now includes a total of 12 states. A nationwide ban on buying or selling fins would tell international trading partners that the United States will not support their shark conservation efforts regardless of future improvements to their fisheries sustainability. Furthermore, banning the sale of shark fins in the United States would likely not result in a significant direct reduction in global shark mortality, because the United States exports approximately one per cent of all the shark fins traded globally, and imports an even smaller percentage of the global fin trade. The UN estimates that 73 million sharks are killed for their fins every year.

A bucket of shark fins being taken off a shipping vesel.

Conservation efforts

Twenty-four per cent of all known species of elasmobranchs (sharks, skates, and rays) are currently threatened with extinction. The cumulative extinction risk for these species is substantially higher than for most other marine vertebrates due to their life history (slow growth, late maturity, and low fecundity). These features make sharks particularly vulnerable to increased mortality from fisheries.

Existing data are often sourced from fisheries logbooks (reported by fishers and onboard observers and taken from landing reports), which may be incomplete, have a low taxonomic resolution, and be influenced by technological changes in fishing gear and preferences for target species. Over the last few decades, population declines of oceanic sharks have been mainly attributed to longline fishing in the North Atlantic, Pacific, and Indian Oceans. There is international concern over the conservation status of pelagic sharks concerning shark bycatch by a multinational fishing fleet operating in the SAO. A coastal nation such as Brazil, Uruguay, South Africa, and Namibia have historically allowed their ports to be used by International fleets from Asia and the European Union to build their fleets and meet quotas. These fleets changed their target strategies over time due to market demands, technological advancements, and declines in abundance of commercial species. Although countries such as Brazil, Uruguay, and South Africa have been creating favourable conditions for many fishing fleets to expand in the area, proper monitoring of these fleets has been inconsistent.

There have been considerable improvements in the management of shark and ray fisheries. First, Indonesia reports the largest landings of shark and rays to FAO and has made considerable progress in the taxonomic resolution of their landings in the past decade. Several species have recovered under strict management regulations. For example, Great White Shark populations increased in California after a prohibition on catches was implemented in 1994. Spiny Dogfish also recovered under strict catch quotas in the United States and the fishery re-opened in 2011.

Sharks - ruthless killers or just misunderstood creatures?
Ragged toothed shark (Carcharias taurus)

Canada has become the first nation to ban the import and export of shark fins, in an effort help preserve a predator under threat. The country is the largest importer of shark fins outside Asia, though shark finning in the domestic fishery has been illegal since 1994. “We’re not the biggest player, but we’re a player,” executive director Josh Laugren, with Oceana Canada, which lobbied for the legislation, told the BBC. “[The bill] is both meaningful in its own right in terms of the trade of shark fins but also hopefully leads the way for other countries to follow suit.” Canada imported more than 148,000 kilograms of shark fins, the majority of which went into shark fin soup. Most came from Hong Kong and China and were likely from finning. Canada is the largest importer of fins in the world, outside of East Asia.

Take-Home Message

Saving a species from extinction requires the same mindset as tackling climate change. One person is not enough to alter its course; all of us need to change how we do things. Try not to support restaurants that serve shark fin soup, spread awareness about the cruel practices of obtaining that shark fin and that shark species are in decline, raise your children to love sharks and not fear them. Last of all when you visit an aquarium or see a shark in the wild from a safe distance, appreciate these ancient creatures and the proper role they play in keeping the ecosystem in balance. Its not only sharks that are being overfished, for more information, click on this link https://conservationcaptured.com/2019/04/26/the-great-ocean-plunder/

 References

https://www.livescience.com/what-if-no-sharks.html?fbclid=IwAR1tiAXWxD-KrWmkniWuRkTIO5u2uvrS9P-6TXDD8ykTSVc6enPArz1B8DY

https://www.floridamuseum.ufl.edu/shark-attacks/yearly-worldwide-summary/

Barreto, R., Ferretti, F., Flemming, J. M., Amorim, A., Andrade, H., Worm, B., & Lessa, R. 2016. Trends in the exploitation of South Atlantic shark populations. The Journal of the Society for Conservation Biology, 30(4), 792–804.

Bombieri, G., Nanni, V., Del Mar Delgado, M., Fedriani, J. M., López-Bao, J. V., Pedrini, P., & Penteriani, V. 2018. Content analysis of media reports on predator attacks on humans: Toward an understanding of human risk perception and predator acceptance. BioScience, 68(8), 577–584.

Davidson, L. N. K., Krawchuk, M. A., & Dulvy, N. K. 2016. Why have global shark and ray landings declined: Improved management or overfishing? Fish and Fisheries, 17(2), 438–458.

Hueter, R. E., & Shiffman, D. S. 2019. Rebuttal to “Response to ‘A United States shark fin ban would undermine sustainable shark fisheries’ I.F. Marine Policy 104 (2019) 85–89.”

Jaiteh, V. F., Loneragan, N. R., & Warren, C. 2017. The end of shark finning? Impacts of declining catches and fin demand on coastal community livelihoods. Marine Policy, 82, 224–233.

Lagabrielle, E., Allibert, A., Kiszka, J. J., Loiseau, N., Kilfoil, J. P., & Lemahieu, A. 2018. Environmental and anthropogenic factors affecting the increasing occurrence of shark-human interactions around a fast-developing Indian Ocean island. Scientific Reports, 8(1), 1–13.

Midway, S. R., Wagner, T., & Burgess, G. H. 2019. Trends in global shark attacks. PLoS ONE, 14(2), 1–13.

Ritter, E., & Quester, A. 2016. Do White Shark Bites on Surfers Reflect Their Attack Strategies on Pinnipeds? Journal of Marine Biology, 2016(2).

Shiffman, D. S., & Hueter, R. E. 2017. A United States shark fin ban would undermine sustainable shark fisheries. Marine Policy, 85, 138–140.

Photo Credits

U.S News and World Report

Blogspot.com

Pixels.com

Tasteessence.com

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