US aquaculture boom raises concerns

 

 

With half of all fish and shellfish consumed now provided by aquaculture in the US, concerns are being raised over the sustainability of output.

 

By the end of this year, the world is projected to reach an unheralded but historic milestone: half of the fish and shellfish we consume will be raised by humans, rather than caught in the wild, according to media reports.

 

Reaching this tipping point is reshaping everything from the oceans to the livelihoods and diets of people across the globe. It has also prompted a new round of scientific and political scrutiny, as researchers and public officials examine how aquaculture is affecting the world's environment and seafood supply.

 

Researchers said the drive to bring fish 'from egg to plate', has the potential to answer a growing demand for seafood worldwide, as well as reduce some of the imports that compose more than 80 percent of the fish and shellfish Americans eat each year.

 

But without technological advances to improve efficiency, it could threaten to wipe out the forage fish that lie at the bottom of the ocean's food chain and potentially contaminate parts of the sea.

 

And consumers will have to accept that they are eating a different kind of fish than the ones that swim wild: ones that might have eaten unused poultry trimmings, been vaccinated, consumed antibiotics or been selected for certain genetic traits.

 

Although there is still debate about farming's share of the world fish supply - the UN Food and Agriculture Organization (FAO) estimates it stood at 44.3 percent in 2007, whereas the PNAS study says it will reach over half in a matter of months - no one questions that aquaculture has grown exponentially as the world's wild catch has flattened out.

 

Media reports states that this trend reflects global urbanisation - studies show that as more people move to cities, they are consuming more seafood - but it is changing the world's seascape as well.

 

Chinese freshwater fish farms are replacing traditional agricultural plots there, according to Karen Seto of the Yale School of Forestry and Environmental Studies, and Nature Conservancy senior scientist, Mike Beck, said some Chinese bays are so crammed with net pens that they are no longer navigable.

 

Moreover, fishermen such as Shannon Moore, who catches salmon in Washington state's Puget Sound, worries about how farmed fish's parasites are affecting wild stocks.

 

US now rank as a minor player in global aquaculture. It accounts for five percent of the nation's seafood supply but the US$1.2 billion in annual production is 1.5 percent of the world's total. In 2006, China supplied 62 percent of the world's farmed fish and shellfish, according to FAO.

 

But farms are expanding in traditional US fishing strongholds, such as New England, the Gulf of Mexico and the Pacific Northwest, and freshwater fish farms continue to operate in states such as Alabama, Arkansas and Mississippi.

 

Freshwater species such as catfish, trout and tilapia still dominate the nation's farmed fish production but such niche products as oysters with regional appellations and sustainably raised shrimp and caviar now fetch a premium in the US.