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112> Chapter 055.13 > Different fishing techniques and their impacts on theenvironment> GILLNETS are anchored at a fixed position in the water. Thereis a low level of bycatch of other species because of the specificsites selected for the setting of gillnets. However, turtles, marinemammals and seabirds can become entangled in these nets.> PURSE SEINE NETS are used to encircle a school of fish. Thenet is then drawn together to retain the fish by using a line atthe bottom, allowing the net to be closed like a purse. There isa low level of bycatch of other species as purse seines targetschools of one species. However, dolphins or turtles are oftencaught as bycatch. Modern purse seines therefore have escapemechanisms.> PELAGIC TRAWLS are funnel-shaped nets that are towed byone or two vessels. The fish are scooped up and captured inthe “cod end”, i.e. the trailing end of the net. Bycatch of otherspecies can be a problem in some areas, depending which speciesis being targeted for trawling.> BOTTOM TRAWLS work in a similar way to the pelagic trawl,but are dragged along the seabed. They are one of the mostimportant techniques used in deep-sea fishing. The nets candamage underwater habitats such as cold-water coral reefs.> BEAM TRAWLS are bag-shaped bottom trawls that are mountedon a heavy metal beam and towed along the seabed. Thisdestroys many fauna living in and on the seabed> LONG-LINES consist of a long main line, up to 100 km inlength, with a large number of short lines (called snoods)carrying thousands of baited hooks. Bycatch is a problem.Dolphins, sharks, turtles and seabirds become trapped on thehooks