This report is a short summa ry of the research activity and results obtained in the project Numsim - Numerical simulation of complex systems involving interaction between elements with large and varying stiffness properties. Main focus of the project has been to develop numerical time-domain simulation models for fisheries and aquaculture systems. The numerical models build on the in-house time-domain simulation framework FhSim. The project has been financed by the Norwegian Research Council (grant 199574/070), The Norwegian Seafood Research Fund (FHF), Multiconsult AS and NOOMAS Sertifisering AS. Research partners in the project have been the Norwegian University of Science and Technology (NTNU), Dept. of Marine Technology and CNR-INSEAN, ltaly. This report covers the research activity at SINTEF Fisheries and Aquaculture.