The peril of Madeira’s sharks

Sharks still belong to one of the animals people are most afraid of encountering but the sad truth is that there aren’t many sharks to encounter anymore. The dangers faced by sharks are countless and include habitat destruction, climate change, chemical pollution and prey depletion. The biggest dangers faced by sharks worldwide, however, are by far those directly or indirectly caused by fishing activity. 

Many countries worldwide still commercially fish for sharks to sell the meat on the market and the fins to restaurants preparing the infamous shark fin soup. Awareness campaigns, such as the one set up by Rob Stewart, have revealed the gruesome practice of shark finning with terrible images of finless sharks being discarded into the ocean and left to bleed to death. On average 73 million sharks a year are slaughtered for shark fin soup and the practice has become so lucrative that organised crime groups, such as the Taiwanese mafia, have infiltrated the business to keep up with the demand. Shark meat is still being sold under false names, event people in Europe. In Germany, for example, shark meat is sold under the name “Schillerlocke”. The tragedy in this is not only that populations of sharks are heavily exploited, the meat is also dangerously saturated with heavy metals. Pelagic sharks, such as the Mako shark (Isurus oxyrinchus), the Hammerhead shark and the Blue Shark (Prionace glauca), are also highly-sought after trophies in Big-game fishing. While many stick to simply catching and releasing the animals, the sharks are often left severely injured or even die during the strenuous battles with sports fishermen on board.

Even if sharks aren’t the actual targets of fishing activity, they still fall victim to it. The overexploitation of their prey populations often drives the animals to opportunistically snap at bait on fishing lines. Most sharks cannot continue to ventilate their gills if they stop swimming, so entanglement in fishing gear, whether it’s a net or a long-line, is a sure death-sentence for the majority of these animals. This sad reality is more than visible by the local public in Madeira; Smooth hound shark (Mustelus mustelus) carcasses as well as those of juvenile Smooth Hammerhead sharks (Sphyrna zygaena) often randomly turn up on beaches or rocky shores. The critically endangered deep-sea shark populations surrounding Madeira and the Portuguese mainland, with their low fecundity and slow growth rate, are particularly vulnerable when it comes to by-catch. The Portuguese have set certain regulations to help reduce by-catch on their long-lines with a maximum time of 36 hours per fishing set. Unfortunately, the stark decrease in the equally vulnerable Black scabbard populations around Madeira forces fishermen to increase their amount of sets during a fishing trip.

I remember going diving in the Maldives, on a dive called the Hammerhead dive. I went on that dive twice a week for three weeks and there wasn’t a single Hammerhead in sight. The dive master in charge told me that, ten years ago, you would fine dozens of Great Hammerheads (Sphyrna mokarran) gliding at depths of 15m. Often you’d even see the occasional Tiger shark (Galeocerdo cuvier) slipping into the groups, patiently waiting to strike one of the weaker, sicker Hammerheads. Shark-finning was officially banned in 2010 in the Maldives but the effect of the exploitation at the time was devastating and is still  visible.

To give provide you with one last horrific statistic to break the man-eater image you may have of the shark; while sharks kill 6 people on average each year, human are responsible for killing over 100 million sharks annually. After hearing this, I think you should be convinced that every shark encounter is a lucky strike and should be cherished.

By Paula Thake