The Bottom pair trawling is operated by two vessels, each towing a trawl warp attached to the bridles in front of the two trawl wings. One of the vessels is handling the trawl and takes the catch.
The major negative impact of bottom pair trawls on the biological environment is related to the capture and frequently discarding of non target sizes and species both of fish and non-fish species.
Source: FAO site, 2017