Optimization of LED fishing lamp allocation based on numerical modeling in Pacific saury fishery

Artificial light plays an important role in commercial light fisheries as a means to attract fish, such as the Pacific saury and squid. To gain an insight into the optimal allocation of light-emitting diode (LED) fishing lamps in the Pacific saury fishery, we present a mathematical illumination model to describe the illumination characteristics of LED modules installed at different angles. The validity of the numerical model was evaluated against the results of an optical experiment and statistical analysis. The results indicated that the agreement between observed and modeled data was good, with a mean error of 8.83%, and that the light distribution varied greatly depending on the angle. The light intensity of the LED module was distributed in the form of a series of concentric circles in the light field. With increasing angle, the maximum illumination decreased and moved away from the light source; also, the horizontally illuminated distance increased but the rate of increase gradually decreased. The illumination attenuation showed different modes between angles after passing the position at which there was maximum illumination. These results could help to further reveal the effects of LED fishing lamp allocations (e.g., installation angle, height, and interval) on underwater illumination characteristics for the optimization of the onboard lighting system and the regulation of the power of fishing lights in the future.