A new study in Biology Letters—conducted by researchers at the Joint Institute for Marine and Atmospheric Research at the University of Hawaii, Ocean Discovery Institute, Comison Nacional Areas Protegidas and Pacific Islands Fisheries Science Center—announces the development of new technology that reduces bycatch rates by utilizing ultraviolet light.
To counter increasing bycatch rates, bycatch reduction technologies (BRT) have been created based on an animal's sensory cues and behavior. The scientists discovered that loggerhead (Caretta caretta) and leatherback (Dermochelys coriacea) sea turtles are sensitive to ultraviolet light wavelengths while many commercially important fish species have UV-absorbing compounds in their eyes that filter UV light. The scientists found that it is possible to exploit this disparity in visual capabilities to develop BRTs to prevent sea turtle bycatch.
"Understanding the sensory physiology of sea turtles and fish species helped us in choosing to use UV illumination," said Wang. "By using UV light, we have a used a selective means of communicating to sea turtles but not to fish."
According to a study, the scientists deployed 11 nets specifically designed to emit UV wavelengths, and found that illuminating gillnets with UV light reduced sea turtle capture rate while having no effect on the total target catch rate for commercial fisheries. In addition, the scientists note that visual-based BRTs can effectively reduce other types of bycatch; nets that are more visible also pose less risk to seabirds. At the time of this writing, testing of illuminated nets has begun in fisheries in Peru, Southern Baja California, Brazil and Indonesia.