Sustainable aquaculture?

By Julian Sudre

It does not take a lot of expertise to camouflage a problem with more quixotic projects. For all that, in times of dire warnings of fish stocks depletion in our seas and oceans, intervention was the source of all secrets. Well, maybe not quite. Finding alternatives to overfishing has shown that aquaculture is following the way of biofuels and yes, human intervention is in all its splendour a remedy that leaves a lot to be desired.

When scientists raised concern about chemicals used in farmed fish that were tested for 14 toxic chemicals known to be carcinogens, such as polychlorinated biphenols (PCBs), dioxins, dieldrin and toxaphene, not only we knew something was up but such move to farm fish and especially salmon at that time demanded answers and fired up bad blood from fish consumers. Surely, the answer is not far to look: the very thing that governments are good at is - clutching at straws. Salmon consumption has increased by 40 per cent in the last 20 years. The annual growth rate in the EU is 14 per cent and much higher in the US. At the same time salmon prices have plummeted, putting the fish alongside herring as the cheapest fresh fish in most shops.

Evidently so as to sustain a profit, Britain's $2bn fish market is no small beer and having recourse to aquaculture was second nature to the Government's ethos. On March 28, EU regulations enacted a law that would make it compulsory to label fish by distinguishing them from wild and farmed after reported fraudulent selling and labelling in these particular markets. Wild fish eat less-processed diet than farmed fish, which alters the balance of the chemical variants, known as isotopes, of which they consist.

According to the Sea Fish Industry Authority, more than 4000 tonnes of sea bass and 1700 tonnes of sea bream were consumed in Britain in 2006 and celebrity chefs have been a part of their publicity. On top of that we have seen the fashionable emergence of sushi restaurants which have flourished all over the world. The converted sashimi-eaters and carnivorous farmed salmons are to be spawning new dynamics in the fish industry. Today, close to 40 per cent of seafood comes from aquaculture. What's particularly detrimental to the ecosystem is the fact it takes a lot of input in the form of other, lesser fish - also called trash fish or reduction fish - to produce the kind of fish we prefer to eat directly. To create 1 kg (2.2 lbs) of high-protein fishmeal, which is fed to farmed fish (along with fish oil that also comes from other fish), it takes 4.5kg (10 lbs) of smaller pelagic , or open-ocean, fish.

Other niggling trends such as the rapid expansion of other species now being farmed, which have much higher feed requirements. Ranched tuna - that is corralled from wild and then fed in anchored pens - dine on live pelagic fish such anchovies, sardines and mackerel. It takes about 20 kg (44lbs) of such feed to get 1 kg of tuna ready for a sushi bar near you. This system was ironically called a reversed protein factory and if the current trend continues, demand for fish oil will outstrip supply within a decade and the same could happen for fishmeal by 2050. Noteworthy is the staggering 37 per cent of all global seafood now ground into feed, up from 7.7 per cent in 1948 according to recent research from the UBC Fisheries Centre. One third of that feed goes into China, where 70 per cent of the world's fish farming takes place. China devotes nearly 4000 sq miles of lands to shrimps farms.

But fish farming also affects the habitat of the fish as they are tightly packed - 50 000 fish in a two-acre area - undeniably damages their fins and scales as they rub against each other and the sides of their cages and becomes sickened with various forms of diseases and infections by parasites which may result in fish lice, fungi, intestinal worms, bacteria and protozoa. British Columbia's Broughton Archipelago received international media attention because of the occurrence of such sea lice where two species were found.

In the same vein, the use of gallons of water in aquaculture each year is one of the main environmental problems, and the release of organic wastes (that, for in instance, act as plants nutrients for harmful algal blooms) and toxic effluents into the oceans have definitely raised worried eyebrows amongst environmentalists.

Last but not least, it is important to note that the business of aquaculture in the long term deteriorates the social well-being of local communities by "poaching" trash fish used for feed production - often the main food for local people - and more to the point, encroaching their rights of food security alongside the displacement of coastal communities.

Now, feasting on fish is incontestably healthy if one is not vegetarian, but gone are the days of enjoying epicurean extravagance without philosophising on the repercurssions of our actions if the fish is farmed.