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SHARKS: Predator or Prey?

What's up with sharks?

Sharks are apex predators at the very top of the food chain and play an important role in regulating the balance of our oceans. They are slow to mature and produce very few offspring. This means that things like shark culling and de-finning are particularly bad for shark populations.

What is de-finning?

De-finning is a practice where the fins of a shark are cut off while still alive. The bodies are often dumped back into the ocean after their purpose has been served. All sharks which suffer this fate have no chance of survival[1] as they either bleed to death, suffocate or are slowly eaten alive by other creatures as they sink to the ocean floor.

What is culling?

Culling is the term for a policy where sharks are caught and, depending on the government, either released or killed. In Western Australia, a ‘catch-and-kill’ policy[2] was implemented in a misguided attempt to ‘protect’ beachgoers from sharks. Under this policy, sharks within a designated kill-zone were authorised to be killed on sight.

Other culling policies include using nets around beaches, however entanglement in the nets poses a real risk to injuring sea creatures. These injuries not only result in lowering the life-span of sharks, but also killing other endangered marine animals such as dolphins and sea turtles.

Why are sharks being targeted?

The demand for shark finning is driven by its position as a key ingredient in shark fin soup, a local cuisine in certain cultures. The soup itself is very expensive and acts as a symbol of wealth. As a key ingredient, demand for shark fins is soaring but the amount of sharks in our oceans are rapidly and unsustainably being depleted to fulfill that demand. According to research[1], this global fin trade has led to the deaths of anywhere in the range of 63 to 273 million sharks worldwide each year.

In terms of culling, the media frenzy sparked by the portrayal of sharks in movies and books like 'Jaws' have unforntunately led to a fear of sharks in the general public. This has led to many governments implementing culling measures as a misguided attempt to help ease the fears of beachgoers. Despite these measures, culling has generally had no effect on curbing the frequency of shark attacks according to results in Hawaii and NSW[3]. In reality, shark attacks are extremely rare, especially considering the millions of hours humans are spending in the water worldwide, each year.

Death Rate of Sharks Caught in 2000

The data from the above chart was taken from research[1] which includes estimates of the number of unrecorded, de-finned and discarded sharks. This death rate includes the number of all de-finned sharks, as well as a proportion of sharks that died shortly after being released due to fishing injuries. Unfortunately, this data only covers sharks that were caught in 2000. It is highly likely that the current actual fatality rate is actually much higher due to unrecorded fishing injuries, the deaths from culling and an increase in de-finned sharks due to higher demand.

Average Human Deaths in Unprovoked Shark Attacks

Across 10 years of recording unprovoked human shark attacks[4] and despite their fearsome reputation in the media, an average of only 6 people worldwide have died each year from shark attacks. This number is extremely low and has generally not seen any significant change despite an increase in culling policies, the amount of humans spending time in the water and better measures for recording shark attacks. When you consider the hundreds of millions of beachgoers every year across the world, an average of only 71 attacks and 6 deaths per year is extremely low.

It should be noted that the above chart only covers the ratio of deaths in recorded, unprovoked shark attacks. In reality, the chances of getting attacked or dying while at the beach is much, much lower. In fact, the probability of dying due to a shark attack is actually much less likely than being killed by a lightning strike![5]

Fatality Rate of Sharks vs. Humans

Why do sharks even matter?

As apex predators, sharks serve a very important role in keeping the population in check. By weeding out the weaker prey, sharks keep the population healthy and prevent prey populations from growing out of control and wreaking havoc on the environment. As culling and de-finning lead to shrinking shark numbers, there would be nothing to balance out the higher numbers of their prey. This would then cause higher competition for food amongst members lower on the food chain in a cascading waterfall effect and the eventual collapse of the ecosystem.

It is of the utmost importance to conserve our shark populations, both for their important role in the ecosystem, and for their significance as one of the oldest living species on earth.

What can we do?

When we go to the beach, it’s important to keep in mind that we are entering the habitat of sharks and as such, we should open ourselves to the slight possibility of an attack and take the necessary precautions. It is our responsibility to ensure our own safety and we should not support shifting the blame onto sharks which are particularly vulnerable to extinction.

Rather than focusing on pre-emptive killing measures which have been proven to be ineffective, we should instead be focusing on taking personal precautionary measures such as setting up shark spotting programs, not swimming during higher risk, low-light periods, and not venturing out too far into the ocean.

Credits

[1] Worm B, Davis B, Kettermer L, Ward-Paige CA, Chapman D, Heithaus MR, Kessel ST, Gruber SH (2013) ‘Global catches, exploitation rates, and rebuilding options for sharks’. Marine Policy 40: 194–204. [Online].
[2] Australian Marine Conservation Society. (Undated). ‘Shark Culling’. [Online].
[3] Kempster R, Collin S. (2013). ‘How to prevent shark attacks’. [Online].
[4] International Shark Attack File. (2016). ‘World Locations with the Highest Shark Attack Activity’. Florida Museum of Natural History. [Online].
[5] International Shark Attack File. (2016). ‘18 Things More Likely to Kill You Than Sharks’. Florida Museum of Natural History. [Online].
Interactive Bubble Chart Code: Michael Currie
Data Sources: [1] Global catches, exploitation rates, and rebuilding options for sharks and [4] World Locations with the Highest Shark Attack Activity

Website by: Jessica Tong (2017)