Comparative study of five commonly used gravity type fish cages under pure current conditions

Abstract

Gravity type fish cages have been commonly used in marine aquaculture for years. However, only limited research efforts have been made to assess the influences of different design parameters on the structural responses of gravity type fish cages. The present study first develops and validates an open-source numerical library under the toolbox Code_Aster for the structural analyses of fish cages. Then, the newly developed library is employed to conduct time-domain simulations to investigate the effects of the main design parameters on the cultivation volumes and drag forces. In this paper, five circumferences of the floating collar, five depths of the net bag, five weights and nine current velocities are considered in the parametric study of five commonly used fish cages. Moreover, regression functions are proposed based on the large number of numerical results to provide accurate predictions for the most concerning aspects in the design process for fish cages. Based on the parametric study, recommendations for selecting fish cage types and practical guides for cage construction are given. This study should be of value to structural designers as well as researchers wishing to optimise cage design.