Light and fish
Light and fish
We provided information about Light and Plants last week. This week, we will share a story of Light and Fish with you.

Every summer, it would raise concerns that a fish farm happens a mass stranding caused by the sweltering heat. Generally, light is known to affect fish physiological responses, including their growth and maturation. Particularly, it is known that various light wavelengths affect diverse physiological responses and cause stress in fish. Additionally, the wavelength of green light is reported for its influence in regulating immune systems, accelerating melatonin output of hormones and for alleviating stress in fish exposed to high water temperatures and toxic environments.

According to studies, ROS (reactive oxygen species) level induced by H2O2 concentration increased significantly at higher temperatures. The concentrations of ROS in the green groups were significantly lower (42%) than the fluorescent light groups. As with the H2O2, LPO (lipid hydroperoxide) levels in the green light groups were significantly lower (34%) than in fluorescent light groups (Fig.1). However, fluorescent light can increase a stress caused by ROS and reduce a physical activity (Fig.2). In addition, it is known that an overproduction of ROS can increase the LPO levels, and negatively affect cell viability by causing cell membrane damage, DNA and proteins denaturation, and an acceleration of apoptosis.

This study is expected that the wavelength of green light will reduce the loss of fish and shellfish caused by repeatedly the extremely hot every year. As a result, LED light may be new technical tool to use in the fish-farming industry.

Fig.1. the ROS and LPO (lipid hydroperoxide) levels in green light and fluorescent light

Fig.2. A sun light spectrum and fluorescent light spectrum

Jae Ho Lee, Ph.D. 
Biologist 
* Next week’s topic : Photon and Electron. 
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