26 August 2013
Source: The Independent
Author: Lewis Smith
It might sound like a fisherman’s tale, but trawlers have to work 25 times harder to catch the same quantity of fish today as they did 150 years ago, scientists have calculated. Fish populations in UK coastal waters are a fraction of what they used to be, and by analysing historical records researchers have calculated that for the effort put in, a modern trawler catches only a small fraction of what its sail-powered predecessors could expect to catch.
The introduction of bottom trawling, whereby metal or wooden bars fixed to nets are dragged over the seabed, was identified as the key factor in the dramatic decline in fish numbers in UK waters. Scientists used the records of two 19th century Royal Commissions to provide the first quantitative estimates of the impact of bottom trawling – which is more efficient but less selective, and also damages the seabed habitats relied on by many marine species – and reveal that it was a “turning point” for UK fish stocks.
They calculated that for the same effort, modern trawlers caught 25 times fewer fish than their counterparts in 1860.