Langoustine Demersal Trawling

003A number of measures have been introduced in recent years to increase sustainability in the langoustine trawl sector of the Scottish fleet.

For most of the east coast, highly selective gear (such as the ‘flip-flap’ trawl or variations thereof) are mandatory for a significant element of the fleet, resulting in a significant reduction in discards.

For example, vessels must use a square mesh panel in their nets, designed to release juvenile fish. Current legislation states that panels have to be of a certain length (3m), be in a certain position from the end of the net (15-18m from the cod end) and be of a mesh size of 80mm (95mm in some fisheries).

Significant numbers of the Scottish fleet voluntarily use square mesh panels with a mesh size of up to 120mm which helps a greater number of juvenile fish escape. Some Scottish skippers have even gone as far as putting in two square mesh panels in an effort to reduce their unwanted by-catch of juvenile fish. Scottish vessels use a thinner twine diameter in their nets than other countries involved in the same fisheries and are restricted to using 4mm single twine. Other countries are allowed to use 5mm diameter double or 8mm diameter single twine. By using smaller twine diameters the nets of the Scottish vessels are more selective and have a significantly reduced by-catch, as well as having less impact on the sea bed due to the reduced gear weight.

Some Scottish vessels also use coverless trawls to fish for langoustines. This gear has the top section of the net cut back, allowing the majority of fish species to avoid capture altogether, whilst still retaining the target catches of langoustines. An enthusiastic programme is currently underway of innovation and development of this and several other net designs for the reduction of discards in the langoustine fleets.