For fish farms, size doesn’t always matter


Lindsey Partos, SeafoodSource contributing editor, reporting from Paris

Published on
March 28, 2010

New research from Scotland questions whether bigger fish farms automatically leave a greater environmental footprint than their smaller counterparts.

Following their investigation of 50 Scottish fish farms, University of Aberdeen scientists concluded that the size of a fish farm should not be the only yardstick when measuring aquaculture’s environmental impact.

Funded by the Scottish Aquaculture Research Forum, the study found that farms do not necessarily have a greater effect on the sea floor than smaller farms. Fish farms generate organic waste in the form of uneaten food and fish feces that sink to the seabed. If allowed to accumulate, they can be detrimental to the organisms that live there.

“Our study joins the growing body of evidence that suggests that the environmental impact of a fish farm cannot be predicted by its size alone,” said lead researcher Dr. Daniel Mayor of the University of Aberdeen’s Oceanlab.

According to the study, the location of a fish farm, and not just its size, is crucial when measuring a farm’s environmental footprint. However, the effects of other factors — such as the speed of the seawater current and water depth — on the actual quantities of fish farm wastes reaching the seabed are less clear cut.

Europe consumes more than 5 million metric tons of farmed fish annually but produces less than 1 million metric tons.

“It is clear that fish farming provides one solution to the increasing global demand for food, but the real challenge is how to feed the world with fish without destroying our coastal environment,” said Dr. Martin Solan, a co-author of the study.

Scottish fish farms are licensed and regulated by the Scottish Environment Protection Agency (SEPA). According to scientists, “sophisticated mathematical modeling techniques” are used to determine the quantity of fish permitted on a fish farm and to predict the maximum tonnage of fish that a particular location can sustainably support without breaching strict environmental criteria.

The study, titled “Factors Affecting Benthic Impacts at Scottish Fish Farms,” was published in 15 March edition of Environmental Science and Technology.

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