In the FishValue project (VærdiFisk) the main goal was to increase the biological and economical sustainability of the Danish Mixed fishery by increasing the gear selectivity and improve the quality of whole and processed fish. A horizontally divided codend was developed in the project to separate four fish species from Nephrops (Nephrops norvegicus) in an upper and lower compartment, respectively, to avoid physical contact between fish and animals with hard or spiny body surfaces. Focus was given to design and placement of a grid in the lower compartment to obtain an effective separation. Square meshes of different mesh sizes in the upper and lower compartment were used to investigate if it is possible to customise the selection of fish and Nephrops separately while retaining the most valuable catch. Quality assessments of the catch were performed to measure whether catch from the two compartments increased quality of whole fish and fish fillets, compared with the standard codend in which the catch components were mixed.
Design and placement of a grid in the lower codend gave an effective separation of all the species investigated when compared to the first version of the experimental codend. Catch from the upper compartment showed a significant quality improvement for whole fish, fillets and Nephrops compared to the standard codend. It was possible to customize the selection of fish and Nephrops separately and at the same time retain the most valuable catch using different mesh sizes of square meshes in the upper and lower codend. In fact, the horizontally divided codend had 10% higher catch rate of Nephrops compared to the standard codend. This more efficient fishery gives less fuel consumption per kilogram Nephrops caught, and may, if evaluated over longer time periods, imply less impact on the sea bottom than when fishing with the standard codend.
This project was coordinated by DTU Aqua and funded by the Danish Ministry of Food, Agriculture and Fisheries and the European Fisheries Fund (EFF).
Research area: Fisheries Technology