Physiological response of the eye to different colored light-emitting diodes in Japanese flying squid Todarodes pacificus

Abstract

To effectively introduce light-emitting diode (LED) lights into Japanese flying squid Todarodes pacificus fisheries, information is required regarding how LED lights affect physiological responses of the squid eye. In order to examine the effects of LED emission-color on squid eyes, we observed the pupillary constriction and migration of black-screening pigment in the retina. The pupils constricted in all squid after exposure to LED lights; the pupils gradually opened and pigment migration occurred. Both of the physiological responses to LED light were affected by blue, green, and white lights, which have wavelengths close to the visual pigment sensitivity peak in T. pacificus (482 nm). However, response rates were much lower under red colored LED, which comprises wavelengths that are far from the visual pigment sensitivity peak. Thus, the eyes of squid responded sensitively to light which included the wavelengths close to the visual pigment sensitivity peak of T. pacificus and responded little to the light which did not include these wavelengths. These results suggest that the eyes of T. pacificus react in different ways to various LED light colors, where the first reaction to a lighting change is the pupillary response, and pigment migration occurs only if the illumination continues.