The most common use of light in fisheries is as fishing lights. Fishing with fishing lights uses the fish behavior that is attracted to and localized by light stimuli. In Japan, it has been used in various forms for a long time, and more
than 30 species of fish have been targeted. The light source began with the torch in earlier times and later changed to oil lamps, incandescent lamps, halogen lamps, and metal halide lamps as light-emitting technology progressed. In recent years, Light Emitting Diode (LED) has been gaining attention as a new light source. Compared to other light sources, LED lamps have a longer life, which reduces labor and costs related to maintenance
and management, and they are smaller and occupy less space. Furthermore, its characteristics are very different from those of light sources previously used in the fishing industry, and it can emit light at specific wavelengths. For example, incandescent
lamps emit a large proportion of long-wavelength components of visible light to infrared light, while LED light can produce specific light with a narrow wavelength range of 460–500 nm for blue, 500–570 nm for green, and 610–780 nm for red, and is
characterized by high energy efficiency. Many researchers believe that these characteristics of LED lights and the color preference and light sensitivity of fish can be used to control fish with lower energy consumption and effectively guide or repel
Studies conducted on the use of LED light
1. Use in squid jigging fishery and saury stick-held dip net fishery
In the case of squid jigging fishery, the results of a practical test showed that the use of blue LED lamps instead of halogen lamps for a part of the fishing lamps for squid, which are highly sensitive to blue light, reduced fuel costs
and increased the catch (Demonstration Test of Energy Saving by LED Fishing Lights on a Medium Size Squid Fishing Boat. 有限会社旺貴水産, Ishikawa, 2010). In addition, the conversion to LED lights is underway in saury stick-held
dip net fishery, where light is actively used as in the case of squid jigging fishery.
2. Use to reduce bycatch
Codends equipped with LED lights and a special escapement port on trawl gear have been reported to reduce bycatch of Chinook salmon (Oncorhynchus tshawytscha) and fish of the genus Sebastes by guiding fish to the escapement port by light (Larsen et al., Fisheries Research, 2018; Hannah et al, Fisheries Research, 2015; Lomeli et al., Fisheries Research, 2012) Many other utilization studies have been conducted.
In addition to the fisheries industry, this technology is also being considered as a technique for preventing fish from wandering into water intake facilities, using the fact that Chinook salmon
and red seabream (Pagrus major
) tend to avoid red lights (Cooke et al., Conservation Physiology, 2018).