ABSTRACT
Using a single-beam, wavelength-scanning, dichroic microspectrophotometer, we measured absolute absorbance, bleaching difference absorbance, and linear dichroism spectra from isolated retinal receptors of the black sea bass, Centropristis striata. We determined, among other properties, the wavelength of peak α-band absorbance (λmax) of the pigment of the receptor cells. Out of well over 100 recordings, we found only 3 spectral types of visual pigment. The shortest-wavelength-absorbing type (λmax = 463 +/- 2 nm) was present only in single cones. Both members of the double cones contained the longest-wavelength-absorbing pigment of the three, with λmax = 527 +/- 5 nm. Rods were found to bear a typical rhodopsin, with λmax = 498 +/- 2 nm. Thus, the retina of this predatory demersal fish appears to use a set of three closely spaced visual pigments, with λmax clustering about 500 +/- 30 nm. This remarkable feature is discussed in relation to photic conditions in the habitat.
