one in two fish from a farm
Friday, September 11th, 2009
They say ‘eat more fish’. And we are.
But with dwindling populations of large, tasty wild fishes, we are now getting more than half of our global annual omega-3 fix from fish farms.
So says a study in the journal PNAS, by a team of researchers led by Rosamond Naylor from Stanford University in the US.
Wild fish catch in Sabah, Malaysia by Helen Scales
Are farmed fishes a problem? They are when they are fed on the millions of tiny fish that are scraped up from the seabed every year and made into fishmeal and fish oils.
And most farmed fish (and crustaceans) are avid fish-eaters. That goes for shrimp, salmon, tuna and many of our favourite eats.
For every kilo of salmon on the supermarket shelves, around 5 kilos of smaller wild fish are used (or 1 to 5 pounds for US readers!).
Far from taking pressure off wild populations, this merely shifts the focus of exploitation to a different point in the oceanic food web.
Can’t we eat vegetarian fish instead? Well yes, we can. Tilapia and Chinese carp are traditionally raised on plants.
But (why is there always a but?), since the early nineties, fish farmers – including many in China – have begun boosting yields by adding fishmeal to tilapia and carp diets.
Now, at a global scale, farms rearing vegetarian fish use more fishmeal than shrimp and salmon farms combined.
So, is there an answer to this fishy issue? Clearly health-conscious seafood lovers will still want their fish.
Naylor and colleagues recommend that the amount of fishmeal used by fish farms could be cut down without harming the product or productivity too much.
Part of the solution will be tighter regulations on fisheries that contribute to fishmeal production, like anchovies and sardines.
And there could also soon be alternatives to fishmeal and fish oil on the market, including extracts from grains, live-stock by-products, as well as GM plants and microorganisms that could be harvested for that all-important long-chain omega-3 fatty acid.
They say ‘eat more fish’. And we are.
But with dwindling populations of large, tasty wild fishes, we are now getting more than half of our global annual omega-3 fix from fish farms.
So says a study in the journal PNAS, by a team of researchers led by Rosamond Naylor from Stanford University in the US.
Wild fish catch in Sabah, Malaysia by Helen Scales
Are farmed fishes a problem? They are when they are fed on the millions of tiny fish that are scraped up from the seabed every year and made into fishmeal and fish oils.
And most farmed fish (and crustaceans) are avid fish-eaters. That goes for shrimp, salmon, tuna and many of our favourite eats.
For every kilo of salmon on the supermarket shelves, around 5 kilos of smaller wild fish are used (or 1 to 5 pounds for US readers!).
Far from taking pressure off wild populations, this merely shifts the focus of exploitation to a different point in the oceanic food web.
Can’t we eat vegetarian fish instead? Well yes, we can. Tilapia and Chinese carp are traditionally raised on plants.
But (why is there always a but?), since the early nineties, fish farmers – including many in China – have begun boosting yields by adding fishmeal to tilapia and carp diets.
Now, at a global scale, farms rearing vegetarian fish use more fishmeal than shrimp and salmon farms combined.
So, is there an answer to this fishy issue? Clearly health-conscious seafood lovers will still want their fish.
Naylor and colleagues recommend that the amount of fishmeal used by fish farms could be cut down without harming the product or productivity too much.
Part of the solution will be tighter regulations on fisheries that contribute to fishmeal production, like anchovies and sardines.
And there could also soon be alternatives to fishmeal and fish oil on the market, including extracts from grains, live-stock by-products, as well as GM plants and microorganisms that could be harvested for that all-important long-chain omega-3 fatty acid.