Brussels, 10th May 2007. A picture taken from space graphically illustrates the damage that is being caused around the world by trawling, one of the most environmentally damaging and energy intensive of fishing techniques.

Brussels, 10th May 2007. A picture taken from space graphically illustrates the damage that is being caused around the world by trawling, one of the most environmentally damaging and energy intensive of fishing techniques.

This amazing satellite photograph shows a shrimp-trawler fishing off the Louisiana coast. Behind the trawler is a “mud trail”, visible evidence of the disturbance to seabed habitats caused by trawling. A similar picture was published in today’s edition of the scientific journal Nature.

Trawls and dredges kill non-target creatures living on the seabed and destroy coral reefs and other hard seabed habitats; they also stir up sediment which then drifts back to the seabed smothering wildlife. According to Drs. Van Houtan and Pauly, the scientists who published the photograph, repeated trawling can permanently modify the seabed and alter the ecosystem for creatures living in the water column above. They are now working with satellite data to try and quantify the amount of sediment that is churned-up and the scale of the subsequent harm done to marine ecosystems by this kind of fishing.

Trawling is also a very energy-intensive method of catching fish, and the contribution that fisheries make to CO2 emissions should not be underestimated. Recent research has shown that in the conventional trawl fishery for Norway lobster, 9 litres of diesel fuel is burnt per kg of landed lobster; this could be significantly reduced by switching to passive fishing techniques. Another example is the Danish flat-fish fishery where the amount of diesel fuel per kg of caught fish could be reduced by a factor of 15 by switching from beam-trawling to the Danish seine.

The absence of duty on marine diesel and direct subsidies for fuel (estimated at US$4.2-8.5 billion per year globally) promote the use of active instead of passive fishing gear. The most direct and obvious way to encourage a shift towards fisheries with less environmental impacts would be to ban direct fuel subsidies and bring duty levels up to those paid by other users of diesel fuel.

Nature article "Ghosts of destruction" (10/5/07).
European Commission press release on the environmental impact and fuel use in Danish flat-fish fisheries (2/2/06).
Environmental Life Cycle Assessment of Norway lobster caught along the Swedish west coast by creels, conventional trawls and species-selective trawls.

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