Visual acuity and spectral sensitivity of Jacopever Sebastes schlegeli

Abstract

Understanding the behavior of Jacopever Sebastes schlegeli to visual stimulation is important and requires determination of visual sensitivity through the use of effective stimulation. In the present study, we measured the visual acuity, visual accommodation and spectral sensitivity of Jacopever. Visual acuity was calculated from the maximum cone density in the retina. In five specimens, the total length ranged from 17.6 to 24.5 cm and the calculated minimum resolving angles and visual acuities were 9.5-10.7 min and 0.09-0.11, respectively. Measurement of lens movement for visual accommodation indicated a mean distance and direction of movement of 0.31 mm and 16.0° in an upward and forward direction, respectively. The direction of accommodation and visual axis measured from the retinal area of maximum cone density were almost identical. The calculated focal distance was 0.74-fold the total length in the nearest point to infinity. We also determined the spectral sensitivity electrophysiologically by recording S-potentials from 45 specimens of total length of 15.4-47.5 cm. The S-potentials were recorded from 300 horizontal cells in the retina. All responses showed a similar spectral pattern, consisting of hyperpolarization in response to various wavelengths of stimulating light; the maximum amplitude of the response was recorded at 522 nm.