Fish Farming Continues to Grow as World Fisheries Stagnate

World seafood production neared 160 million tons in 2006, the last year for which there are data.¹ (See Figure 1.) The growth over the previous year was entirely due to increased fish farming, or aquaculture, which increased by more than 3 million tons, an annual addition that has been fairly consistent over the last 10 years.² In contrast, fish caught in the wild declined for the second year in a row and dropped to almost 4 million tons below the peak catch in 2000.³

About 75 percent of the fish caught and produced each year are destined for human consumption.⁴ This adds up to about 16.5 kilograms of fish per person annually on a global scale.⁵ In 2004, more than 2.6 billion people depended on fish for at least 20 percent of their animal protein.⁶

People in China eat the most fish, with an average 25.8 kilograms live weight equivalent per person, compared with a figure of only 8.2 kilograms in Africa.⁷ People in North and Central America eat 18.6 kilograms, while Euro­peans consume 19.9 kilograms a year.⁸ Not surprisingly, people who live in coastal areas eat more fish than others in the same country or region; in Oceania, per capita consumption is 23.5 kilograms.⁹ Differences within continents are also common: in the United States, the average fish consumption is 24.2 kilograms while in Mexico it is 11.6 kilograms; in Spain, the figure is 42.9 kilograms, compared with 34.3 kilo­grams in France, 29.5 kilograms in Sweden, and 19.8 kilograms in the United Kingdom.¹⁰

Globally, total seafood production grew at a slower rate than meat output for 8 of the last 10 years.¹¹ But aquaculture growth continues to far outpace all other animal food sectors, with average annual rates of 8.6 percent over three decades, compared with 2.8 percent for meat production during the same period.¹² Projec­tions indicate that seafood demand will con­tinue to grow along with population and incomes, especially as people in developing countries increase their overall consumption of animal products.¹³

The world's fisheries have remained relatively stable over the last 15 years: about 50 percent are being fished at full capacity, 25 percent are underfished, and the remainder are overex­ploited, depleted, or recovering.¹⁴ As a result, the U.N. Food and Agriculture Organization predicts that maximum wild fish capture has already been reached.¹⁵ Most of the stocks of the top 10 fished species are being fully fished or are overexploited, and studies have indicated that even in the most stable fisheries there have been declines in the most valuable species, such as tuna.¹⁶

Asia and the Pacific region dominate global aquaculture production, accounting for more than 90 percent.¹⁷ China is by far the world leader, with more than 45 million tons pro­duced in 2006-about 70 percent of global output and more than half of the total global value from aquaculture.¹⁸ The next closest producer is India, with just over 3 million tons.¹⁹ The only country outside this region in the top 10 producing countries is Chile.²⁰ (See Figure 2.)

At the same time that wild marine catches face further decline or stagnation, aquaculture production offers further growth potential. In China, more than three quarters of the fish supply comes from aquaculture, while the average for the rest of the world is 20 percent and rising.²¹ Sub-Saharan countries in Africa have the largest untapped potential because of resources like clean water and unused land.²²

Historically, most of the world's aquaculture has focused on species that are relatively low on the food chain, including seaweeds, shellfish, and herbivorous or omnivorous species like carp.²³ However, recent trends indicate stronger growth rates in carnivorous species like shrimp and salmon will continue, especially as demand increases.²⁴ (See Figure 3.)

Due in part to this trend, growth in aquaculture now drives global fishmeal and fish oil production. Until recently, fishmeal and fish oil were used primarily for pig and poultry production; today nearly 50 percent of fishmeal and 87 percent of fish oil is used in aquaculture.²⁵ In 1948, only 7.7 percent of wild-caught fish were reduced to fishmeal or fish oil, but that number has grown to 37 percent.²⁶ Because fishmeal and fish oil depend on overly taxed marine fisheries, increasing production on a large scale is unlikely.²⁷

Increasing the use of fishmeal and fish oil in aquaculture raises health and environmental concerns. The rendering process used to pre­pare these products concentrates the toxins found in the fish, including carcinogenic dioxins, which accumulate up through the food chain to people who eat contaminated fish.²⁸ This problem is seen clearly in farmed salmon, which consistently have significantly higher levels of dioxin than their wild counterparts.²⁹ Another troublesome toxin that accum­ulates in fish is mercury, which is especially dangerous for children.³⁰

Dependence on rendered fish also decreases the efficiency of farming fish, as fish-derived feed products require more energy to produce than plant-based ones.³¹ For farmed salmon, as much as 90 percent of all energy inputs go into providing food for the salmon.³² Indeed, farmed salmon can require five times more energy per edible protein unit than farmed shellfish.³³

Fish farms themselves, especially ones that raise carnivorous fish, can be a large source of water pollution, including nitrogen and excess nutrients that can create toxic blooms and dead zones.³⁴ Because fish are often raised in high densities to maximize profit, they can require antibiotics and other treatments for diseases, most of which end up in the water.³⁵

These problems have led some researchers and fish farmers to consider alternative prac­tices that would minimize environmental harm while allowing increased aquaculture produc­tion. For example, integrated fish farming works at the ecosystem level, using a combination of fish, shellfish, and aquatic plants to filter wastes and provide a self-sustaining source of food.³⁶ Integrated fish farming has been used outside major urban areas to raise fish for food and treat human wastes at the same time.³⁷

With an ongoing food crisis and a growing world population, seafood production could potentially play a vital role in addressing food security and meeting development goals. Fish is highly nutritious and can be an important source of vitamins, minerals, and protein, even when consumed in minimal amounts.³⁸ A recent World Bank survey showed that small-scale fish farming consistently pays off for workers by raising income, creating stable work, and increasing food supplies.³⁹ However, not all seafood production is created equal: overfishing is linked to poverty, leading to fewer jobs and taking away an important source of income in developing countries.⁴⁰