April 12, 2020

Global Shark Threats

Despite having ruled our oceans for over 400million years , sharks are currently under serious threat. Our unsustainable actions as humans has severely effected shark populations world wide. It is estimated that over 100million sharks are caught and killed each year and shark populations have declined by almost 90% globally. Bycatch, illegal fishing and the demand for shark fins are the driving forces behind the continued exploitation of this species. Highly industrialised fishing fleets and even smaller artisanal fisheries around the world are currently fishing sharks towards extinction. 
Bycatch is the accidental catch of non-target fish species and other marine life. Non-selective fishing techniques such as longlines, bottom trawlers, gill nets are hugely responsible for a staggering amount of marine life accidentally caught and killed via these unsustainable fishing techniques. According to the IUCN, bycatch is one of the most devastating threats facing sharks. Longline vessels, typically targeting tuna, have the highest levels of shark bycatch. Sharks often make up more than a quarter of the total catch. Indonesia is the largest shark fishing nation and catches on average 100,000 tons of sharks per year. The majority of these sharks are caught as bycatch on tuna fishing vessels. 
Sharks are being caught and killed for their fins to feed the demand for shark fin soup. Shark Fin Soup is a traditional Chinese delicacy served at important banquets and symbolising wealth. The shark fin is the most valuable part of the shark – sometimes costing as much as  400$ per kilo. 
This increase in demand for shark fin soup has led to sharks being targeted solely for their fins. Shark finning involves the removal of the shark fin from the body, whilst the remainder of the body is discarded . An extremely wasteful practice. The targeting of sharks for their fins is pushing this species to the brink of extinction. 
Apart from their high value fins, sharks also also being caught for the use of their skins in fashion, cartilage as dietary supplements , liver oils for use in cosmetic products , meat for consumption, and shark teeth / jaws as souvenirs. 
Shark Fins for sale at a fish market
Shark fins for sale at a fish market in Indonesia. Photo by : Etoile Smulders
Shark Fin Soup
Restaurant displaying shark fin soup . Photo by : Etoile Smulders
Despite having worldwide regulations put in place to manage fisheries, limit shark catch numbers, and protect endangered species, there is a lack of enforcement of these laws in international waters. IUU ( illegal , unreported and unregulated ) fishing remains one of the greatest threats to marine ecosystems due to its aggressive ability to wipe out entire stocks of fish and other species.

Other threats such as pollution,  marine habitat degradation due to unsustainable coastal development and climate change are also all factors that are negatively impacting shark populations.


Sharks are long living creatures that grow and reproduce slowly . These biological factors make sharks particularly vulnerable to overfishing . It is hard for shark populations to recover after they have been depleted.


As apex predators , the depletion of shark populations will have adverse affects on the marine food chain and ecosystem balance.  Sharks play a significant role in the ecosystem by controlling and maintaining species lower in the food chain. By removing the sick and weak, they keep the balance between other marine competitors and help maintain species diversity within our oceans. Their existence is crucial to the health of our seas.


So what would happen to our seas if they actually disappeared? Lets look at a case study from the past. On  the east coast of the United States of America, large predatory shark populations, had declined drastically due to overfishing. These sharks are known predators of the Cownose ray, along with other species of rays and skates and smaller sharks.


When the large predatory sharks disappeared  , the population numbers of the animals that they feed on increased ,  because the larger sharks were not there to predate on them and ‘control’ the population. The overpopulation of these species, specifically the cownose ray caused devastating consequences to the shellfish industry in the area. Cownose rays eat shellfish, and now there were simply too many rays and shellfish populations took a massive beating.


All organisms in the ocean are interconnected via the food web. Removing one level, will have dire consequences  for the other levels. This is why its so important to have healthy shark populations. As apex predators, their existence is crucial in order to keep balance within our marine environment.


Written by: Etoile Smulders