Ontogeny of Visual Ecophysiology in Black Sea Bass (Serranidae: Centropristis striata)

      Black sea bass (Centropristic striata) are protogynous hermaphrodites that support major commercial and recreational fisheries from Nova Scotia to Florida. Optical micro- and macrohabitats experienced by this species vary widely throughout ontogenetic development; juveniles inhabit shallow estuarine nurseries and adults migrate to deeper offshore hard-bottom and reef ecosystems. Because there are unavoidable tradeoffs between luminous sensitivity and spatial and temporal resolution in the evolution of visual systems, we examined potential ontogenetic and circadian changes in the spectral sensitivities, temporal properties, and absolute sensitivities of the black sea bass visual system using corneal electroretinography (ERG). Juveniles were less sensitive to dim light than adults under photopic conditions, but both life stages had comparable scotopic sensitivities.  Flicker fusion frequencies of juveniles were faster than those of adults. Spectral sensitivities were broadest for juveniles and blue-shifted in adults, consistent with migration from coastal waters that are maximally penetrated by green-yellow wavelength to deeper coastal water maximally penetrated by blue-green wavelengths.  Collectively the visual systems of juvenile and adult black sea bass thus correlate with the photoclimate experienced by each respective life stage.