Spectral sensitivity and purkinje shift in the retina of the lemon shark, Negaprion brevirostris (Poey)

Spectral sensitivity of the lemon shark, Negaprion brevirostris (Poey), was determined using the ERG from the intact animal under scotopic and photopic conditions. A Purkinje shift was found upon moderate light adaptation. The peak of the scotopic spectral sensitivity function did not match the λ max of the pigment. Recordings from the isolated retina and eyecup preparation were made to see if the pre-retinal media or tapetum lucidum influenced spectral sensitivity. Only the tapetum had a slight effect. We hypothesize the presence of a cone input influencing scotopic spectral sensitivity.