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Dryad

Data from: Behavioural red-light sensitivity in fish according to the optomotor response

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Jul 09, 2021 version files 31.37 KB

Abstract

Various procedures have been adopted to investigate spectral sensitivity of animals, e.g., absorption spectra of visual pigments, electroretinography, optokinetic response, optomotor response (OMR), and phototaxis. These works have led to various conclusions about animal vision. However, visual sensitivity should be evaluated consistently for a reliable comparison. In this study, we retrieved behavioural data of several fish species that used a unified procedure for the OMR test and compared the sensitivities to near-infrared light. Besides cavefish that lack eyes, some species were not appropriate for the OMR test because they either stayed still or changed swimming direction frequently. Eight fish species out of 13 species tested were OMR positive. Detailed analyses using goldfish, zebrafish, guppy, medaka, stickleback, and cichlid revealed that all the fish were sensitive to light at λ ≥ 750 nm, where the threshold wavelengths varied from 750 nm to 880 nm. Fish opsin repertoire enabled the perception of red light. In contrast, the copy number of long-wave-sensitive (LWS) genes did not necessarily improve red-light sensitivity. The duplication of LWS and other cone opsin genes that have occurred extensively during fish evolution might not aid increasing spectral sensitivity, but provide some other ophthalmic function, such as enhanced spectral discrimination.