Sea change

Globally, aquaculture now supplies more than half of all seafood produced for human consumption, but could the industry’s growth have disastrous environmental consequences? Mark Rowe reports
Humans have come relatively late to fish farming. Although the Chinese are documented to have reared inland fish 2,400 years ago, global aquaculture has only become mainstream over the past 30 years. But we’re making up for lost time – aquaculture is now the world’s fastest growing food sector, increasing by 6.5 per cent a year and worth more than US$100billion globally, according to the UN, and now providing half of all the seafood that people consume.

Around the world, aquaculture employs more than 16 million people, the vast majority of whom are smallholders, including 3.5 million fish farmers in Indonesia and five million in China. The UN Food and Agriculture Organisation (UNFAO) reckons  that there are at least 600 species of fish and crustacean being harvested in farms, contributing around 13 per cent of global animal-protein supply. The UNFAO also sees seaweed as an important additional source of non-animal protein.

Positive effects
The case for aquaculture appears strong – the devastation of global fish stocks is well documented, so surely we should all welcome an alternative source of fish protein, aping the way that we’ve bolstered livestock production. Then there’s the swelling global population. ‘Aquaculture is an immense part of the solution,’ says Dr Rohana Subasinghe, a senior aquaculture officer at the UNFAO. ‘Captured fisheries have almost stagnated. But with a global population rising to nine billion, the demand for fish is going to grow. If we don’t meet that demand, either consumption will decline – with implications for human health – or the price will go up.’

These trends underpin the boom in aquaculture, according to Are Kvistad of the Norwegian Seafood Federation (FHL). ‘It’s being driven by the fact that there’s a limit to how much fish you can take from natural stocks from the sea, and we have almost reached that limit,’ he says. ‘There are limits – we can’t just fish and fish, and so we have to look at other ways to produce food. That explains why so many countries are looking at aquaculture.’

Subasinghe’s view is that aquaculture has the capacity – if supported and developed in a regulated and environmentally sensitive manner – to contribute significantly to improving the well being of poor and disadvantaged communities in developing countries, and to achieving several of the Millennium Development Goals, especially those related to poverty reduction and food and nutrition security, environmental protection and biodiversity. Environmentalists such as WWF agree, arguing that, when done properly, some forms of aquaculture can ease the pressure on wild fisheries and provide a much-needed income to coastal communities.

A darker side
But Subasinghe’s qualification – that aquaculture must be ‘environmentally sensitive’ – alludes to widespread concerns about its negative impacts. Fish farms are linked to the spread of disease, the dilution of wild stocks through cross-breeding by escapees, pollution, the devastation of mangroves, concerns over the use of wild fish to feed farmed fish, and conflict with predators such as seagulls, seals and starfish. ‘We’ve seen inadequate governance, which gives rise to environmental and social problems,’ he says. ‘Greed has been a problem. Even if people recognised that there was a problem, they just covered it up. Where you don’t have enforceable laws, development will go haywire. Aquaculture is a commodity, so you need checks and balances.’

Escapees are an intractable concern. WWF has expressed fears that they breed with wild stock and dilute the natural gene pool, potentially affecting the long-term survival and evolution of wild species. Wild Atlantic salmon populations have dropped steeply in the past 30 years – by 80 per cent between 1970 and 2000 – according to WWF, which believes that farmed salmon are putting pressure on the remaining wild populations. At the same time, farmed salmon production in the North Atlantic ocean increased 55-fold and wild salmon now encounter escapees in Norway and along the west coast of Canada.

In Scotland, over the first six months of this year, escapees amounted to 30,986 fish, with holes in nets, equipment failure, human error and bad weather being blamed. Last year, nearly 41,000 fish escaped from Scottish fish farms; in 2011, the total was 416,000.

Norway, too, has had its problems. ‘Back in 2006, we had a horrible year,’ says Kvistad. ‘We had 921,000 escaped fish; we had hurricanes, which explained some of it. Now, we have large fines for fish escapes and improvements to make stronger nets and gear. Last year, we had 35,000 escapes, so it’s down, but we’re aiming for zero. We have to ensure that we keep the fish in the nets. Our main species in aquaculture is farmed salmon, but wild salmon has a big population, so we have to take care of both of them.’

Road to extinction
Elsewhere, in Fiji and on other Pacific islands, badly constructed fish farms are allowing invasive species, such as tilapia and mosquito fish, to compete with native species. A six-year study by Wetlands International (WI) found that 85 per cent of wild fish catchments had been invaded by escapees. ‘Native and endemic fish faunas are being locally extirpated, which, in the context of small islands, can put them well and truly on the road to extinction,’ said a WI spokeswoman.

Wild fish stocks are also exposed to diseases, such as salmon louse and sarcocystis, an emerging disease in rainbow trout that causes sores and affects growth. Global shrimp farming has been hit by early mortality syndrome, which is caused by a particular bacterium and can lead to 100 per cent mortality. The UNFAO says that disease treatment and damage costs the aquaculture industry US$6billion a year.

According to the Salmon & Trout Association (Scotland; S&TA), the migration of wild salmon between fresh and salt water normally keeps sea lice at bay. ‘Adult wild salmon are perfectly adapted to cope with a few sea lice and background levels of these parasites occur naturally in the sea,’ says Guy Linley-Adams, a solicitor working with the Friends of Loch Etive, a charity that’s protesting against the expansion of fish farming (see Scotland’s salmon rows).

However, the advent of salmon farming has triggered a fundamental change in the density  and occurrence of sea lice. The S&TA, citing figures produced by the Scottish Salmon Producers Organisation, says that in June this year, more than one third of salmon farms – 47 farms – on the Scottish mainland and in the Hebrides were in areas where average sea-lice numbers exceeded the industry’s own limit. ‘The salmon smolt [juveniles] come down the river and have to swim through a cloud of juvenile lice, and they simply get killed,’ says Linley-Adams. ‘Even one or two mature female sea lice per fish within a set of cages housing hundreds of thousands of farmed salmon amounts to a rampant breeding reservoir pumping billions of mobile juvenile sea lice out into the local marine environment.’

Location, location, location
The proximity of farmed fish to wild stocks also causes environmentalists unease. Fish farms require the shelter of bays and estuaries to avoid damage from storms and currents, so there are a limited number of suitable locations.

According to Linley-Adams, 30 fish farms in Scotland ‘are simply in the wrong place. When fish farms were first built, for obvious reasons they were placed in sheltered areas, but they were positioned right by the mouths of the rivers where wild salmon smolts enter the loch, putting the farmed and wild fish into direct conflict.’

Norway spends 50 million Norwegian krone (£5.35million) a year tackling the problem of lice and many farms deploy wrasse and lumpfish to  eat the lice that attach to farmed fish. The FHL promotes additional mitigation measures, requiring fish farms to lie fallow for at least two months between rearing cycles to reduce what it describes as ‘infection pressure’.

As with intensive terrestrial farming, WWF and other organisations also worry about the use of antibiotics to treat infections in fish farms, as well as anti-fouling agents such as copper. They also argue that nutrients in unused fish feed and fish faeces can cause local algal blooms. These blooms lead to reduced oxygen in the water, which can, in turn, trigger the production of ammonia, methane and hydrogen sulphide, which are toxic to many aquatic species. The FHL, however, contends that emissions are typically substances that are naturally part of the marine ecosystem, and that fish and benthic fauna utilise uneaten feed and faeces that fall to the seabed.

The wider environment has also suffered tremendous damage from aquaculture. The mangroves of Asia – vital nurseries for wild fish stocks, sources of wood for building and buffers to storm surges – have been battered by oil palm plantations but also razed to make space for shrimp farms.

About a fifth of all mangroves have been lost since 1980, mainly cleared to make way for farms that often get choked with waste, antibiotics and fertilisers, according to a UN study released last year. Unsustainable practices include the reliance on high-nutrient chemical inputs that severely degrade the land quality; after five to ten years, shrimp ponds are abandoned and investors establish new ponds in other mangrove areas. ‘The short-term benefits of this shifting aquaculture tend to be reaped by an elite of investors, while rural communities permanently  lose their natural resources,’ wrote the authors of the report.

‘Mangrove ecosystems are rare – they cover a small area of the globe,’ says one of those authors, Dr Hanneke Van Lavieren of the UN University’s Institute for Water, Environment and Health. ‘That makes them even more at risk from aquaculture and development. You find mangrove forests in areas perfect for shrimp farming. The water is brackish, they create sheltered areas, the water is flushed naturally. But the intensive nature of aquaculture makes it unrealistic for mangroves to carry out their natural role of filtering out pollution.’

Fishmeal concern
Just what we use to feed farmed fish is another concern. Most farmed marine fish and shrimp species are carnivorous. They’re either fed whole fish (mainly in the case of tuna) or pellets made of fishmeal and fish oil.

In both cases, the fish used as feed are generally caught from the wild, according to WWF. The amount of feed needed is staggering – WWF says that 22 kilograms of wild-caught fish is needed to produce just one kilogram of farmed tuna; four kilograms of wild-caught fish is needed to produce one kilogram of farmed salmon.

Many of the fish used as feed – mostly anchovies, pilchards, mackerel, herring and whiting – are already fished at, or over, their safe biological limit. So instead of relieving pressure on the marine environment, says WWF, aquaculture actually contributes to overfishing.

Norway takes 30 per cent of its fishmeal – mainly stocks of anchovies – from the southern Pacific off Peru and Chile. Global dumping of fishmeal, according to the FHL, amounts to about 20 million tonnes a year, enough raw material to increase aquaculture in Norway tenfold.

More sustainable and nuanced practices are now being encouraged. For fish feed, the International Fishmeal and Fish Oil Organisation (IFFO) has developed a certification programme that complies with the UNFAO’s codes for responsible fisheries. By 2015, the IFFO hopes that 40 per cent of global meal and oil production will be certified.

‘The growth of aquaculture has to be sustainable, both economically and environmentally,’ argues Kvistad. ‘It’s the major challenge. If you don’t have good enough controls, then you have a problem with escapees, disease and access to feed and raw materials. You have to ensure that these raw materials come from sustainable fisheries and plants.’

Signs of hope
Encouragingly, Van Lavieren is confident that the environmental record of fish farms is improving. ‘In the past, we saw mangroves as having little ecological value – they were just mosquito-infested swamps that we wanted to cut down anyway,’ she says. ‘That has all changed.

‘The Philippines, Vietnam and Indonesia now recognise that aquaculture has been unsustainable,’ she continues. ‘They were left with vast areas of degraded, polluted and unusable wastelands. I’m not saying there’s no longer any bad practice, but I don’t see people coming in  and just chopping down mangroves and putting intensive systems in place now. The countries have paid the price through loss of income and diseased shrimps.’

Another potential landmark was reached in 2010, with the establishment of the Aquaculture Stewardship Council (ASC) by WWF and the Dutch Sustainable Trade Initiative. As with the Forest Stewardship Council (for wood) and the Marine Stewardship Council (MSC; for fish), the aim is that a product displaying the ASC label will be guaranteed to have come from sustainably farmed sources.

The MSC is providing advice on establishing a chain of custody between aquaculture producers, seafood processors and retail and food-service companies. So far, the ASC has certified 454 products sold in 22 countries, including the UK,  the USA, Taiwan, Spain and Australia, and certified farms in Costa Rica, Honduras, Malaysia, Ecuador, Indonesia, Taiwan and Vietnam.

‘ASC is entirely voluntary,’ admits Chris Ninnes, the body’s chief executive. ‘It’s too early in our history to quantify the reduction of impacts, but we set some pretty challenging benchmarks on feed and rigorous standards for effluent and chemicals. I’m not suggesting that the ASC is a panacea, but as more and more farms become certified, it becomes a tool that can encourage others to raise standards.

‘Aquaculture has to come to terms with the impacts of the stuff that feeds the fish,’ he continues. ‘A lot of it is drawn from various commodities and a lot of fish oil and feed is used, and the state of some of these fisheries is poor, especially in Southeast Asia.’

Another major issue, warns Ninnes, is the cumulative impact of aquaculture. One fish farm in a sheltered bay will have limited or isolated impacts, he says, but hundreds set up adjacent to one another, often with little or no regulation, is a different issue. ‘What is the current capacity the environment has for a certain amount of aquaculture?’ he asks. ‘That requires several agencies because of the geographical scale involved. When should the water be left fallow, what are the impacts of disease treatments?’

A question of capacity
Despite these caveats, the MSC believes that aquaculture can be a force for good. ‘Aquaculture has a role,’ says the MSC’s Kate Wilcox. ‘There’s a huge amount of fish farming, and it has a strong role in feeding the world and providing livelihoods. We firmly recognise that we both have a role in helping retailers and consumers make sustainable choices. Robust standards are about minimising the impacts and the concerns that different groups might have.’

The ASC claimed a breakthrough this summer when it secured a global standard for the salmon-farming industry, and it will now work with third-party entities to certify salmon farms that are in compliance with the standards. Yet others argue that certification has serious limits.

Barely five per cent of global aquaculture production is certified, according to the Institute of Aquaculture at the University of Stirling. What’s more, the institute argues, the potential for further growth is limited by the fact that demand for certification is firmly oriented towards Western markets, whereas most seafood is consumed elsewhere, notably in Asia, where most fish and shrimp farming occurs.

This means that many fish farmers will, in effect, have two markets: a certified, high-standard system that sells into the minority Western market; and a lower standard, mass market business for the rest of the world. ‘Certification has a part to play, but it also has serious limits,’ says Professor David Little of Stirling’s Sustainable Aquaculture Research Group, who was involved in the research. ‘Consumption of farmed fish in the global north is small compared to consumption in the global south. If you want a global impact, don’t kid yourself you will do it by getting supermarkets in Europe on board if you don’t address the Asian market. Aquaculture is growing most quickly in exactly the places where there are most people, and where many people are very poor.’

Little argues that the West instead needs to change its mindset towards the pressures that lead to mass production of farmed fish in the developing world. The UNFAO estimates that China produces 70 per cent of all farmed fish, while Asia as a whole accounts for 91 per cent. ‘The approach seems to me almost neo-colonial, telling producers what to do rather than engaging with local governments, NGOs and community groups,’ Little says. ‘The main concern in Asia is still about eating more, rather than environmental impacts.’

A shift in the mindset of major retailers and supermarkets would do a good deal in terms of raising standards in a meaningful way, Little suggests. ‘The big global supermarkets have huge investments in Asia, and they have the potential of a lot of market muscle to move through some of the agendas, but I don’t see that happening,’ he says. ‘They’re quite content to protect their global reputation in Europe and North America because consumers are more aware there. But I think they take the view that it isn’t good for their business in Asia to do that there.’

New horizons
Despite the seemingly positive steps of recent years, there’s one extremely large challenge looming – aquaculture is going to have to get much bigger, very quickly, if it is to keep up with demand. Global farmed fish production stands at around 140 million tonnes a year; by 2030, this will have to top 260 million tonnes. Experts believe that to do this, the industry must tap into places where aquaculture is either embryonic or non-existent.

Brazil is set to become a big player, according to the UNFAO. ‘Two thirds of the world’s fresh water is in the Amazon, so much more can be done with aquaculture in that part of the world,’ says Subasinghe. ‘The Yellow River in China is probably already at maximum capacity of production, so it won’t have much room for expansion. African countries such as Ghana, Uganda, Kenya and Mozambique have excellent potential.’

According to Subasinghe, the industry will also need to be inventive – doubling or even tripling the uses of a fish farm. ‘There will be multiple uses for fish farms, with oysters and molluscs feeding off the waste from the farmed fish, taking the excess nutrients from the shrimps,’ he says.

The nature of aquaculture will change significantly along the way, suggests Ninnes. ‘Aquaculture will diversify and there will be some increase in the number of species that are farmed,’ he says. ‘The operations will be increasingly efficient and that will not just be driven by standards but because it makes business sense to be efficient with resources and energy use. Many businesses are still in the transition phase where they don’t quite see the value of these steps. Aquaculture isn’t going away, it will grow above other trends of protein production.’

Bargaining power
But there are pitfalls as aquaculture expands, according to Subasinghe. ‘There’s a trend in commodity production to become more and more corporate,’ he says. ‘If that happens in aquaculture, we lose the value. It isn’t only the fish we need, we also need the employment. We have a responsibility to make sure aquaculture contributes to a better world, higher incomes and livelihoods, not just producing fish but producing fish in an environmentally and socially acceptable manner. We have to work with small-scale farms, so that they have bargaining power. But aquaculture will be much more sustainable than it was 20 years ago. We’ve learnt from the mistakes.’

And development may bring some surprising farmed species to our dinner plates, points out Kvistad. ‘Cod has been tried in farms, but people can’t make money just yet – there are so many wild cod in the Barents Sea, and farmed juvenile cod require different feed,’ he says. ‘But cod will be an interesting subject one day.’

Despite her documentation of the damage caused to mangroves by aquaculture, Van Lavieren, too, is a supporter of sustainable fish farming. ‘It makes good sense to use aquaculture,’ she says. ‘It isn’t a bad practice per se, and it’s one of the good ways to provide food. There’s no way we can depend on wild fish or shrimps.

‘The mind boggles when you look around and see what we’ve done with farming – growing crops in the middle of the desert in Qatar in a sustainable way,’ she continues. ‘In that respect, humans are very inventive. The problem is that we get to the point of real environmental damage – we learn the hard way before acting. I’m not saying there are no threats left, but I’m optimistic. It’s a fact we’re going to farm fish, so let’s do it sensibly.’

Box: Scotland’s salmon rows
Although the Scottish government sees aquaculture as a major source of revenue, the expansion of fish farms hasn’t pleased everyone, and new plans for bigger farms are being met with fierce opposition. The Salmon & Trout Association (Scotland) says that fish farming is ‘destroying west Highland and Hebridean wild salmon and sea trout stocks’ and has pushed iconic sea trout fisheries such as Loch Maree beyond recovery. Salmon abundance (adults returning to Scottish coasts) is now less than 20 per cent of that seen 50 years ago, according to the association.

Now, opponents are gathering to fight plans for an expanded rainbow trout farm on Loch Etive, south of Glen Coe. Proposals by Dawnfresh for a 14-pen rainbow trout farm have been revised in the face of criticism, but the new plans for ten 80-metre-circumference cages fed by a permanently moored feeding barge, remain fiercely opposed.

‘Loch Etive already has five fish farms and local people are worried that this proposal will tip the loch over the edge from being a tourism destination into something much more industrialised,’ says Guy Linley-Adams, a solicitor who represents the Friends of Loch Etive.

Box: Farming wild caught fish
The global appetite for bluefin tuna has had a devastating effect on the fish’s population in the Mediterranean and off southern Australia, according to WWF. But far from taking pressure off the fish, aquaculture has, until now, merely exacerbated the problem.

Typically, more than half the catch in the Mediterranean is farmed, but this merely involves catching wild tuna – many of them juveniles – fattening them up in cages and exporting them to Japan for sushi. According to the European Commission, despite global initiatives to limit exploitation, bluefin tuna populations have fallen by around 80 per cent since 1970. In 2010, the breeding stock of Pacific bluefin tuna was estimated to be about 22,000 tonnes, less than a third of the estimates from 15 years earlier.

Recent moratoriums could help rebuild stocks, and in September, the Northern Committee of the Western & Central Pacific Fisheries Commission, whose signatories include Japan and the USA, agreed to reinforced regulations that limit Pacific quotas, the first such regulation to designate a numerical target.

The European Commission argues that bluefin breeding would speed up the recovery. Until now, however, scientists have been unable to rear the fish in captivity. But earlier this year, a European initiative, known – in classic Euro-jargon – as SELFDOTT (Self-sustained Aquaculture and Domestication of Bluefin Tuna), achieved a breakthrough that could set the tuna on the path to recovery.

Researchers at the Spanish Institute of Oceanography managed to glean a viable mass of eggs from captive bluefin tuna. The resulting larvae grew to a weight of one kilogram in a little more than three months. The growth was achieved in floating cages without the use of hormones and the researchers expect many of the juveniles to reach adulthood within four years and then go on to reproduce.

November 2013

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