Development of the retina in spotted sand bass Paralabrax maculatofasciatus (Percoidei: Serranidae) larvae under culture conditions

Abstract

We describe the development of the retina in spotted sand bass Paralabrax maculatofasciatus larvae under culture conditions, using histological techniques. Retinal development in the spotted sand bass larvae followed a pattern previously described for other teleost species. Two periods of active differentiation were observed. The first occurred during the yolk-sac stage (from hatching to day 2 after hatching) as preparation for the onset of exogenous feeding. During this period, the eye showed negative allometric growth (growth coefficient = 0.5). At the time of first feeding (day 2), total length (TL) was 2.58 ± 0.26 mm (mean ± SD), the eye became pigmented and single cones were the only photoreceptors observed in the retina. After first feeding, a slightly positive allometric growth of the eye was observed (growth coefficient = 1.11). The second period occurred during the transformation to juvenile stage. Presumptive double cones were first observed on day 14 (TL = 5.37 ± 0.58 mm) and presumptive rods on day 22 after hatching (TL = 7.23 ± 0.99 mm). From day 22 onwards, the visual system was formed by a duplex retina with both rod and cone photoreceptors present.