Meeting Abstract

3.9  Jan. 4  Sensory Ecology of Low-Light Vision in Kelp-Forest Rockfish (genus Sebastes). REILLY, Christian; Reed College heron@reed.edu

An animal’s ability to behave appropriately in response to the events in its environment depends on the ability of its sensory systems to detect those events. The absolute limits to low-light visual sensitivity are thought to be set by thermal noise arising in the rod photoreceptors and caused by temperature-induced rhodopsin isomerizations. I examined the low-light sensitivity of a group of kelp-forest fishes (genus Sebastes) using the electroretinogram (ERG) to determine whether low-light sensitivity of rockfish is significantly affected by environmental changes in temperature, and, if so, how changes in low-light sensitivity translate into changes in ecological interactions. I introduce a computational model of the submarine light environment used to assess the ecological significance of variations in retinal sensitivity. Changes in threshold sensitivity vary the length of time that environmental light levels are greater than measured retinal threshold (visaul activity window). The model predicts that local average seasonal temperature changes (~4 &deg C) have no significant affect on the visual activity window, but greater temperature changes, such as those associated with increasing sea-surface temperature trends (~10 &deg C), could significantly affect visual activity windows. Visual activity window durations are compared between diurnal species and nocturnal species, and the greater sensitivity measured in nocturnal species is found to translate into a 3-5 hour advantage in daily visual activity window over the diurnal congeners. In addition, local rockfish community diel activity patterns are predicted to be sensitive to potential increases in coastal light pollution.