DFPO Denmark North Sea sole
Certified as sustainable in June 2012.
Species: Common sole (Solea solea)
Location: North Sea, FAO statistical area 27, ICES Area IV.
Fishing methods: Demersal Trawl, Set Nets (Gill and Trammel)
Number of fisheries: 1
More about Sole
Common sole is a widely distributed species, extending from the Mediterranean and Northwest African coast, as far south as Senegal, to the Irish Sea, southern North Sea and Skagerrak and Kattegat. In autumn, triggered by falling temperatures, sole leave the shallow inshore waters and migrate to warmer offshore grounds (this represents the end of the fishing season for the fishery under assessment). In severe winters sole populations may form aggregations in deeper, less cold parts of the North Sea and English Channel. The central eastern North Sea (ICES area IVb) where the fishery under assessment occurs is near the northern limit of the species, however these are also some of the grounds with the highest concentrations of sole, and important nursery grounds. Spawning occurs in spring, peaking in May, triggered by rising sea water temperatures. Although it has been shown that spawners return to the same spawning grounds each year, it is not known whether recruits return to the grounds where they were born. Females are batch spawners producing on average around 350,000 eggs (35cm fish) per year. Sole are nocturnal and olfactorial feeders, spending the day buried in the sediment. The blind side othe sole has sensory organs to detect prey. Sole feed on polychaete worms (Arenicola marina, Lanicespp. and Nereis spp.), molluscs and small crustaceans. During the short pelagic phase, larvae feed ocopepod nauplii.
More about the fishing methods
The demersal or bottom otter trawl (single, twin and pair) is a towed fishing gear designed and rigged to have bottom contact during fishing, towed by large trawl vessels, typically in excess of 15m. A demersal trawl is a cone-shaped net consisting of a body, closed by a codend and with lateral wings extending forward from the opening. The two towing warps lead from the vessel to the otter boards which act as paravanes to maintain the horizontal net opening. These boards typically weigh between 0.5–2 t and drag across the seabed . The boards are joined to the wing-end by the bridles which herd fish into the path of the net. On very rough substrates special rock hopper gears are used.
Set net (Gill net/ Trammel net)
The Gill net consists of a single netting wall kept more or less vertical by a float line and a weighted ground line. The net is set on the bottom, and kept stationary by anchors on both ends. Each net is approximately 125 cm high (from the seabed) and 50m long with a monofilament mesh size of 92mm. Typically lengths of nets are joined together, making long nets sometimes up to several kilometres in length. Vessels in this fleet typically carry between 100 and 300 nets
The trammel net used by this fleet is a triple mesh net, anchored to the seabed with a total height of around 1.5m. The inner central mesh is typically 150mm, sandwiched between 2 outer mesh layers (trammels) of 350mm. By having an inner panel of small mesh netting, loosely hung between the two outer panels of large mesh netting, when a fish strikes the net it pushes the small-meshed netting forward through the large mesh, forming a pocket in which it is trapped
Both gill nets and trammel nets are set before dark, generally parallel to the tide. Nets are usually left in the water overnight and hauled during the day.
Approximately 400 tonnes in 2008 and 380 tonnes in 2009.
Sole is mainly exported as chilled fish to the Netherlands, Germany, Italy and Spain.
Actual eligibility date
14 August 2011