Assessment of natural density of distribution for fish by the catches at light stations

Abstract

Algorithm for calculation of illumination produced by shipboard lights at the sea surface and underwater is developed and implemented with Microsoft© Office Excel software. The surface illumination is calculated for the fishing vessel STR-420 with the light equipment for saury fishery. Irregularity of the lighting around the vessel is shown that depends on the lamps arrangement. Optimal scheme of the lamps arrangement is proposed for a new saury trap with the catch volume > 7000 m³. The optimal arrangement provides more regular lighting and therefore larger illuminated area for attraction of fish with positive phototaxis, as saury. Relationship between natural density of saury distribution and its catch per trap is determined for this trap.