Extensive research has been conducted on various fish protection systems in an attempt to reduce the entrainment and impingement of fishes at hydroelectric facilities as well as at once-through-cooling thermal power plants. Many of these systems involve elaborate screening apparatus that are expensive and not always effective.There are possibly more cost-effective options which includes integrated systems such as lights and coarse physical barriers.
Our technology a new underwater LED device (Light Guidance Device, LGD, ATET-Tech Inc.) that use red, green and blue LED light modules capable of producing different color combinations flashing at frequencies of 1 – 40 times per second to address species specific responses of fish and other aquatic organisms. Various spectral/frequency combinations produced by the LGD have been demonstrated effective at either attracting or repelling juveniles of a wide variety of fish species. LGD technology can either be used alone or integrated with another system.
ATET-Tech’s integrated system can include a bar rack or louver design complemented with a unique light based system for improving performance of said louver or bar rack system. The addition of specific wavelengths for a fish behavioural response will allow an increased spacing and greater array angle to shore, thereby resulting in less material, lower construction costs and less issue with biofouling organisms.
Other technologies can also be integrated with the LGD including coarse angled screens, barrier nets, fish pumps and fish return systems. Integrated fish protection systems are flexible, can be low cost, and have recently shown promise for further research and development. Integrated systems are necessary given the well-documented species-specific responses to different stimuli, the plasticity of diel patterning and circadian rhythms in fish in response to changing light cues, and the influence of various environmental parameters such as temperature and turbidity on the performance of fish protection systems.
Our Laboratory at Carleton University (Ottawa, Canada) has been evaluating ATET’s LGD system for several fish species. This technology is very unique for fish management applications because it enables the user to adjust light frequencies and intensities to guide fish of different species and life-stages.