Fish are friends, not food

Today there are countless threatened species. Many of these are top predators, the removals of which have the potential to trigger detrimental trophic cascades. One top predator that is threatened by human pressures is the shark.

 

Great White Shark (Melissa Smith 2013)

DID YOU KNOW Sharks are 200 million years older than dinosaurs and the largest known shark was 20 metres long (Defenders of Wildlife 2013).

Sharks are beautifully aerodynamic creatures, designed for stealth and grace in the water. Their stealth, sense of smell and razor sharp teeth are the reasons they rule the oceans, as a top predator, around the world (Defenders of Wildlife 2013).

Nevertheless, while many sharks eat marine animals such as fish and seals, many more feed on crustaceans, molluscs and plankton. Unfortunately, all sharks have copped a bad reputation, as a result of media sensationalism and ignorance.

 

Finding Nemo (Finding Nemo 2003)

 It is the human-created stereotypes that have planted the immediate fear for sharks. But the truth is, most sharks are harmless to us. 

Indeed, Bruce, Anchor and Chum from Nemo are a better representation of the average shark: " I am a nice shark, not a mindless eating machine...", well said...  

In Western Australia, sharks are now being culled as a result of humans’ fear. The culling of sharks in these waters is random and uncontrolled, which means any shark can be caught and killed, whether or not they are a threat to humans. Remember, not all sharks attack people. 

Sharks are also being caught for their fins. This practise is a major contributor to overfishing, as well as being cruel and wasteful (sharks are thrown back into the water once the fins are removed).

Hammerhead sinking to ocean floor after being de-finned (Western Australians for Shark Conservation 2014)

Aside from the direct action being taken against sharks, there are indirect effects that are contributing to the rapid decline of sharks worldwide. Climate change, pollution and habitat destruction are some examples (Save Our Seas Foundation 2014).

But what does this all mean? What are the consequences?

Because they are slow in developing, and have low reproductive rates, sharks are slow to recover from rapidly changing environments or external pressures. A decrease in shark populations lead to  trophic cascades. This has been seen on several occasions. Off the coast of North Carolina, USA, shark populations were severely depleted due to human pressures. In a healthy ecosystem, the sharks preyed upon Cownose rays, which in turn fed on scallops. The coastal human population also relied on the scallops. Once the shark numbers faded, there was an excess of rays, which severely damaged the local scallop community. Not only did the removal of this shark population lead to a unhealthy ecosystem, the livelihoods of the people who relied on the scallop population were negatively impacted (Save Our Seas Foundation 2014). 

It is clear that sharks are important for the health of our oceans and for our own wellbeing. We must prevent the decline of shark populations by stopping culling, shark finning and by preserving their habitats and reducing pollution.

Sign the petition to end shark culling here: http://www.marineconservation.org.au/petitions.php/9/save-wa-sharks-stop-the-cull

Sources

Defenders of Wildlife 2013, Defenders of Wildlife, Washington, DC, viewed 8 April 2014, <http://www.defenders.org/sharks/basic-facts>

Save Our Seas Foundation 2014, Save Our Seas Foundation, Switzerland, viewed 8 April 2014, <http://saveourseas.com/threats/predatorloss#3>