Five good reasons to preserve sharks
1. Sharks play a key role in marine ecosystems
Sharks are a key piece in nature’s great puzzle. As top predators, sharks help keep marine ecosystems in balance. Scientists warn of the negative cascading effects of removing sharks from marine ecosystems. In both terrestrial and marine ecosystems, significant removal of top large predatory taxa can create an imbalance between predator and prey abundances and diversity, causing a degraded or negative effect on the dynamics of lower trophic levels or a shift on the entire ecosystems. It is therefore believed that sharks play an important role in regulating structure, function and resilience of marine communities. For example, research has shown that overfishing of sharks in the Atlantic Ocean led to an eight-fold increase in their prey, the cownose ray, which then fed on bay scallops and led to the collapse of the scallop fishery. Conserving sharks is essential for conserving marine biodiversity and human livelihoods.
2. Sharks are worth more alive than dead.
On top of keeping the oceans healthy, shark tourism is a multi-million dollar business. Whale shark watching alone in Australia generates roughly US$4 million per year. Shark and ray watching by divers brings in €17.7 million to the Canary Islands each year and 429 jobs. Shark diving is increasingly popular in many parts of the world. While the tourist industry can make money from live sharks year after year, fishermen make a profit from a dead shark just once.
3. Killing sharks just for their fins is a wasteful (and cruel) practice
Because shark fins command high market prices, many fishermen cut off fins, which represent around 5% of the body weight, and throw the rest of the shark back to die. This practice is known as “finning”. Like killing an elephant for its tusks, shark finning is an extremely wasteful practice. Should fishermen be allowed to throw 95% of their catch overboard? Although finning is illegal in some countries, legal loopholes and the high value of the trade is fodder for illegitimate and illegal fishing practices. Most of the time, when we eat, serve or buy shark fin, we are encouraging these reckless and increasingly illegal practices.
4. Sharks can be toxic
As the oceans become increasingly polluted, methylmercury and other heavy metals concentrate in the flesh of top predators such as sharks and tuna.
Methylmercury, which is the organic form of mercury, is a neurotoxin and can impair brain development in fetuses and children as well as affect the central nervous system in both adults and children. Pregnant women and children are therefore advised not to consume predatory fish such as shark.
Several studies show that Hong Kong residents, who have very high seafood consumption (62kg per capita per year versus the world average of 16kg), have much higher mercury concentrations than European subjects. Hong Kong males with higher levels of mercury were twice as likely to be subfertile than those men with low levels of mercury.
In addition to heavy metals present in shark meat, shark fins are bleached to give a creamy white colour by being soaked in hydrogen peroxide. The finishing touch to preserve the fin involves formaldehyde, a known carcinogen. On top of all this, shark cartilage has not been proven to be “anti-cancer” as millions of people around the world believe it is.
A study by scientists from the University of Miami showed high concentrations of neurotoxins in shark fins. The BMAA neurotoxin found is linked to neurodegenerative diseases in humans, including Alzheimer's and Lou Gehrig's Disease (ALS). The study, published in the Marine Drugs Journal in February 2012, suggests that consumption of shark fin soup and cartilage pills may pose a significant health risk for degenerative brain diseases.
5. We all care about our grandchildren
Caring about our offspring’s future and wanting to leave something behind for them does not make us “activists”. We are fully aware and informed about this severe environmental problem and will not be able to claim ignorance to future generations. When our grandchildren ask us if we played a part in this ecological tragedy, we want to be able to answer: “no, we didn’t”.
Weiger, W., Smith, M., Boon, H., Richardson, M., Kaptchuk, T., Eisenberg, D. (2002) Advising patients who seek complementary and alternative medical therapies for cancer Annals of Internal Medicine: 137(11) pp.889-903.