- Trawling kills dolphins and other large fish, incidental to the catch.
- All fishing creates by-catch, which includes fish, sharks, marine mammals, dolphins, seals, turtles and sea birds. These are thrown back into the sea, dead or dying. This can be delayed until the point of returning to port.
- Purse Sein nets in the Eastern Tropical Pacific deliberately target dolphin schools, because tuna swim between those schools. This also catched whales and whale sharks. Not studied in the Pacific, Indian and the Atlantic (but expected to be similar). Since 1959, an estimated 7 million dolphins have been killed in the Eastern Tropical Pacific.
- When small purse sein nets using light attraction are used, small fish, juveniles and endangered species are killed as by-catch
- Drift nets can be strung together and can stretch over 60kms. The by-catch was so dire that the UN has banned drift netting in the high seas. Now nets less than 2.5km are permitted, but in the EU, all driftnetting was banned in 2002
- Long lines of up to 150km with thousands of baited hooks dangle from them. In this case, the by-catch is birds, which try to eat the bait, and are drowned when caught. In Australian waters, up to 300,000 are killed each year. 26 species of bird, including 17 species of albatross are in danger of extinction, because of long lines
- Bottom Trawling can be done in waters up to 2km deep. It covers 50% of the continental shelf which is analogous to clearfelling forests of 150 times the forest area on land. It is a long beam that drags a net, with tickler chains scouring the sea floor before it. 15 million square km are trawled annually. It destroys habitat and diversity. Turtles and other endangered species are by-catch.
- Trawling destroys coral, habitat for bio-diverse fish populations
References for the ArgumentsEdit
- The National Oceanic and Atmospheric Administration state of the coast report (US) estimated that 27 million metric tonnes of by-catch occur in commercial fishing worldwide annually. 48,000 turtles are estimated to be caught by shrimping.
- Evidence for 7 million
- Conservation Biology Institute