Salt with your Shark Sir?

Sharks may not be the first thing that you think about while waiting for your fish'n'chips, but it may well be what's being served. Rock salmon, huss, flake; all are pseudonyms for types of shark, many from around our local waters.

The seas around the UK boast a great variety of sharks. Huge Basking sharks to smaller dogfish, sleek predatory Blues, Makos and even the occasional Hammerhead. You may not be able to see them through the murk, but they are there.

Eating shark in this country is certainly not new. In the sixties 35,000 dogfish a day were being landed in Plymouth alone. This over-fishing soon led to the decimation of our dogfish populations (catches have been falling since the 1980's) and demand is now met by imports from the US.

The other great pressure on the shrinking shark populations is the rapidly growing shark-fin trade. This is generally assumed to be an eastern phenomenon, but the decline of existing fish stocks, coupled with the spiralling price paid for shark fins, has changed all that. Recent figures show that nearly 30% of fins imported to Hong Kong, the centre of the fin trade, now come from Europe

In the Spanish fishing port of Vigo we watched around 4,000 sharks being landed and sold in just one morning. Most of those were Blue sharks, mainly juveniles yet to breed, but there were also Makos, Threshers and Porbeagles. No wonder the angling club of Great Britain's' catches have dropped from 3000 to 86 a season

Around the world sharks are under threat, with 25 species now on the ICUN list as endangered or vulnerable. The UN has warned that "Unless action is undertaken promptly, the future of many shark populations is very bleak".

So it's just another conservation story, what does it matter?

It could just be that the sharks have a card up their sleeve, and it is one that we gave them - mercury. Mercury is a largely atmospheric pollutant, which means that it gets almost everywhere. In the sea it becomes methyl mercury, which is highly toxic to humans and can lead to blindness and sterility.

Mercury accumulates up food chains and, as apex predators, sharks are very near the top. Unfortunately for us we are at the very top. The US FDA recently warned pregnant women and children not to eat shark because of its high mercury content. Shark fins from Bangkok market were found to contain up to 42 times the permitted level of mercury. The shark fin industry is obviously very worried about this; if shark were poisonous then this would end their industry even faster than extinction caused by over fishing.

So what can be done? Well don't eat shark (or swordfish) until it has been proven safe, especially not if you are pregnant. Support the SharkTrust (www.sharktrust.org) and sign their online petition, they'll even send someone to your dive club to give you a shark talk.

There is no proof yet that UK shark populations carry excess amounts of mercury, but growing concerns on both health and environmental grounds are causing many to examine more closely what is coming with their chips

Sune Nightingale