Response Of Settling Oyster Larvae, Crassostrea Virginica, To Specific Portions Of The Visible Light Spectrum

Settlement site choice was used to rest the ability of competent-to-settle oyster (Crassostrea virginica) larvae to detect specific portions of the visible light spectrum. Larvae were permitted to settle on illuminated or shaded sides of vertically oriented settlement substrates. Five light treatments were used, including white light (400-700 nm), three fractions of white light; red light (600-700 nm), green light (450-575 nm, peak at 525 nm), blue light (400-500 nm, peal; at 425 nm); and total darkness. In total darkness, no settlement preference for either side of the substrates was detected. In all light treatments, larvae settled in significantly higher numbers onto shaded surfaces than illuminated surfaces. Crassostrea virginica larvae respond to most portions of the visible light spectrum, unlike many previously studied marine invertebrate larvae. This ability may reflect the diverse light conditions in the largely estuarine habitat of this species