Light-mediated behaviors, such as visual foraging and migration, have been the focus of numerous studies spanning a wide variety of taxa; however, the role of UVR in these and other behaviors has generally been given less attention.
Recently, the effects of UVR on aquatic ecosystems have been examined more closely as a result of increasing U V-B radiation reaching the Earth's surface due to stratospheric ozone depletion. UVR is now known to penetrate deeply into many freshwater and marine systems, and organisms occupying all trophic levels are susceptible to damage or mortality from UVR exposure. Behavioral avoidance is one means by which organisms can reduce exposure to damaging radiation. Both laboratory and field experiments have demonstrated that many species are negatively phototactic to UV and shorter-wavelength visible light. In addition, UV photoreceptors have been reported in a variety of fish and invertebrates, suggesting that UV vision may be prominent in aquatic organisms. These UV photoreceptors are thought to be used for navigation, communication, enhanced foraging, and possibly UVR avoidance. Given the presence of negative phototactic behaviors as well as UV vision, UVR may be an important factor influencing migration and abundance patterns as well as predator-prey and intraspecific interactions.
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