Trawling 'ploughs' the deep sea floor Habitat damage Bottom
trawling by fishermen may be even more damaging than previously
thought, affecting the seabed as seriously as intensive
ploughing of farmland erodes the soil, say Spanish scientists.
Bottom trawling - dragging nets across the sea floor to scoop up
fish - stirs up the sediment lying on the seabed, displaces or
harms some marine species, causes pollutants to mix into
plankton and move into the food chain and creates harmful algae
blooms or oxygen-deficient dead zones. "Bottom trawling has been
compared to forest clear-cutting, although our results suggest
that a better comparison might be intensive agricultural
activities," they write in a study published on the journal
Nature. During the 20th century, more intensive farming
techniques and changes in land use reduced the diversity of
landscapes almost everywhere, say the researchers. Ploughing up
land exposes the top soil to erosion by wind and water,
destroying or weakening nutrients in the soil which