With our world population ever increasing, so does the proportion of pollution we are generating. It is not only our terrestrial environment that is affected by what we do on land, but also our marine environment.
Once waste of any kind reaches the sea, so begins its journey with tides, currents, and wind.
Research, journals, news reports have all confirmed that our oceans are suffering form increased pollution, acidification, and over-fishing. But what we rarely hear about in the media is how severe our marine eco-systems are being contaminated with toxic chemicals. The reality is, agricultural run-off, industrial waste and sewage pollution is changing the chemistry of our oceans. This is in addition to rising ocean temperature and ocean acidification, which also contribute to a mixing bowl of problems turning the waters of our world into waste sinks where our dirty habits are flushed into unseen depths. That is, until we realize what we put in the ocean filters through the food chain and eventually makes its way back to our dinner plate, bowl of soup, or ‘cancer-fighting’ supplement.
Results revealed alarming levels of neurotoxins present in subjects, further confirming shark tissues have high concentrations of BMAA (Beta-methylamino-L-alanine), a toxin linked to degenerative diseases like Alzheimer’s and Lou Gehrig’s. Contrary to the traditional Chinese belief that sharks ‘don’t get cancer’ and possess properties capable of curing human ailments, sharks actually carry high levels of chemical pollutants and heavy metals such as Mercury and Cadmium. Past publications claimed sharks were immune to cancer (2002 book 'Sharks don’t get Cancer'), thus fuelling an entire industry marketing shark products as ‘boosters’ for human health. However, science based studies have repeatedly discredited these theories, and exposed the reality that sharks are in fact one of the most toxic fish in the ocean. Humans have been reluctant to abandon their hopes that sharks could aid in prevention and treatment of cancer and bone health, and today millions of people are still consuming shark products.Image © MJ Arsenault
This means they feed on an array of smaller fish species, which have in turn fed on even smaller organisms and Algae. Every amount of toxin is passed up through the food chain and is eventually consumed by the shark in the way of a tasty Tuna or Seal. This process is called Biomagnification, and is the result of our top ocean predator ingesting the toxins prevalent in other organisms over a long period of time. In turn, when humans consume shark’s fin or other shark products (i.e. cartilage supplements) we are consuming more toxins than any other fish in the sea!
Biomagnification is literally the ‘magnified’ result of toxins moving up the food chain to become more potent as they are past from one organism to the next.
Instead of dissolving in water, most persistent pollutants entering our oceans do not degrade and lodge themselves in the fatty tissues of marine life. Because of this, toxins become more concentrated over time, as one fish eats another, and slowly spreads higher levels of toxicity throughout the food chain. This is called Bioconcentration. Every predator absorbs the toxins of their prey, and increases the concentration of their own toxicity, until they are devoured and add to their predator’s stores of toxins.Image © eco-odyssey expeditions 2011
Only half a century ago, people believed the oceans were so vast, so deep, that nothing humans could do would ever alter or damage it. This was the age of Industrial Revolution, a time of productivity, development, and advancement. But somewhere along the way we lost sight of our growth, neglected to pay attention to our effect on the oceans, and planted the seed for the environmental collapse we are facing today. Ocean pollution from industry, farming, and land pollution causes inorganic chemicals like PCB’s, Dioxins, and heavy metals (Mercury, Cadmium) to persist, infect, and permeate marine eco-systems from the bottom up, leaving no organism unaffected. Although some pollutants may degrade, disperse; the overwhelming amount of waste entering the waters of our world is no match for what the oceans can do to withstand the devastating effect of pollution.
Yes, sharks are toxic. They are the powerful predators who consume years of accumulated toxins in the food chain, riddling their bodies with unprecedented amounts of chemicals. Researchers at the University of Miami found shark had levels of BMAA as high as 144-1,836 ng/mg (nanograms per milligram). Healthy humans tested for the neurotoxin had little or no traces of BMAA, while those affected with Alzheimer's and Lou Gherig's disease had traces up to 256 ng/mg. These findings could spark interesting debates about the effect of BMAA in our bodies, and how this amino acid, brought on by land pollution and agricultural run-off, has a role to play in degenerative disease and ocean pollution.
It is bad enough that humans now understand and study the effects of ocean pollution, greenhouse gas emissions, and ocean acidification, but worst of all is that industry, and profit-driven economies are still built on practices that make matters worse for our oceans; and ultimately, us. Sharks may carry the most toxins, but species like Tuna, Swordfish and Salmon have increasing levels of mercury, and are not recommended for children or pregnant women. These metals, poisoning our oceans, now pose a threat to human health.
Despite available information and valuable scientific studies, a staggering $3 million was spent on shark cartilage supplements in America in 2011, and the consumption of shark fin soup is dominant in multiple countries around the world, contributing to a global decline in shark populations. And so our mixing bowl of ocean issues continues to fill, bordering an overflow of problems that will not only challenge the survival of entire ocean eco systems, but also threaten the ability of the planet to survive without them.
Without ocean health, our demise is imminent.
Citation: Anahad O'Connor, "Shark cartilage may contain toxin". New York Times, 08.03.12. http://well.blogs.nytimes.com/2012/03/08/shark-cartilage-may-contain-toxin/ Andrea Goth, "Biomagnification: Why a dead shark is more dangerous than a live one". Shark Savers. Karen Franklin & Sarah Grieco, "Shark Fin soup poses risk for Alzheimer's study". NBC San Diego. 2.03.12
This fear-inducing fish, the eternal poster shark for the "Jaws" fuelled anti-shark sentiment, the powerful Great white, also known as the 'White shark' is the ocean's top predator.
The White shark is also the largest of predatory fish, growing to lengths of over 6 meters (20 feet).
This shark is found in every ocean on the planet, and can adapt to sub-tropical and temperate waters alike. These sharks are the most feared of all shark species, and their jagged, exposed, multiple rows of teeth are certainly their most threatening feature.
Great whites have about 300 teeth at any given time, while back rows continually develop new teeth to replace ones lost over time. These sharks predate huge mammals such as seals, and they need strong jaws and sharp teeth to consume such large prey!
Despite the widely held belief White sharks are 'man-eating machines' and 'monsters of the sea', they are actually vulnerable, ancient, vital marine creatures, and deserve the respect of man.