Exit Windows as an alternative selective system for the Barents Sea Demersal Fishery for cod and haddock

During a 4-year research period, trouser trawl experiments were performed to assess the cod and haddock selection capacity of a codend fitted with two 130 mm exit windows. These windows, which were 10 meshes high and 45 meshes long, were inserted in the rearmost part of the codend. The results showed that this codend was very efficient in releasing large amounts of undersized fish and the 50% retention length (l50) was far above the minimum landing size (MLS) for both the analysed species (the MLS for cod is 47 cm, 44 cm for haddock). For cod, the mean l50 values varied between 53.6 and 57.3 cm and the mean selection range (SR) values from 6.8 to 9.3 cm. Haddock was measured during two trials with the mean l50 at 50.5 and 50.6 cm; and the mean SR values at 6.3 and 6.0 cm. Total catch weights varied between 0.7 and 6.6 metric tonnes. In some cases an important effect of catch weights upon the l50 could be detected.