Comparison of Different Light Spectra in Fishing Lamps

Abstract

It is widely recognized that some fish species are attracted to light. Thus, the use of artificial light in some fisheries has been one of the most advanced and successful methods to control fish behavior for capture purposes. In Thailand, fishing with lights utilizes metal halide, incandescent or fluorescent bulbs with various colors. The type of lamp depends on the engine due to the light output requirement for the underwater light intensity. The color of light used differs for different fishing grounds, with the main colors being white, red, green and blue. This research investigated the light spectrum of three types of fishing lamps using a profiling reflectance radiometer system (PRR2006). The lamps tested were: 1) a metal halide light with a spectrum and radiation of about 0.1–0.8 W.cm^-2 and the main direction of the light was 90°–120° and 240°–270°, 2) an incandescent lamp with the spectrum and main direction of the radiation about 0.2–2.0 W.cm^-2 and 120°–240°, respectively, and 3) A fluorescent
bulb with a spectrum that ranged from 0.8 to 2.0 W.cm^-2 depending on the color and the radiation surrounding the cylindrical bulb. The main light color radiated by the metal halide lamp was red and by the incandescent lamp was yellow and orange. The results determined that with metal halide and incandescent, lights, the long wavelength had a high intensity although it was diminished to nearly 0 W.cm^-2 at 10 m below the sea surface. Only the 500–600 nm range of the spectrum could radiate into deeper waters.