Meeting Abstract

74.6  Sunday, Jan. 6  Comparative sensitivity of the eyes of ontogenetically migrating crustaceans WHITEHILL, E.A.G.*; FRANK, T.M.; Clemson University; Harbor Branch Oceanographic Institute, Florida Atlantic University whitehi@clemson.edu

Ontogenetically migrating crustaceans live at shallow depths as juveniles and migrate deeper into the water column as adults. Therefore, the juveniles and adults of these species experience vastly different light environments, and may have photoreceptor adaptations that enable them to efficiently process the available light in their respective environments. Measurements of eye aperture, as well as photoreceptor dimensions, of three ontogenetically migrating species, Systellaspis debilis, Oplophorus gracilirostris, and Gnathophausia ingens, were compared to those of the non-migrating Notostomus elegans and N. gibbosus. Based on the optics of the eye, the eye of the adult ontogenetic migrators is more sensitive than those of the juveniles, while the sensitivities of the juvenile and adult eye of the Notostomus species were not significantly different. These data indicate that due to the optics of the eye and photoreceptor size, the juvenile ontogenetic migrators are adapted for the brighter light environment in shallower waters, and the adults are adapted for optimum sensitivity to the dimmer light field at greater depths. The eyes of non-migrating juveniles and adults have similar sensitivity, reflecting their similar visual environments.