In Situ Observations of Fish Attraction to Light-Emitting Diodes on an Undersea Observation Deck

Abstract

Many fisheries employ fishing lights to manipulate the behaviors of target fish and to attract them toward the light; however, relatively few long-time observations of fish attraction have been performed in the field. Here, an underwater observation deck was used to examine the differences in the fish-attracting effect of light-emitting diode (LED) lights on the number of attracted fish and on their behavior in the field, using white-edged rockfish as the target species. A total of 604 ± 324, 307 ± 203 and 171 ± 106 white-edged rockfish individuals were attracted to the observation window when it was illuminated with blue, green, and red light, respectively. Under the blue light, fish remained for 133.6 ± 129.8 s around the window, while under the for green and red light, they stayed for 72.5 ± 76.7 s and 45.7 ± 52.2 s, respectively. The longer time spent under the blue light may have result in an increase in the number of fish counted, and this would be related both to the transparency of this wavelength underwater and to the visual sensitivity of white-edged rockfish. Other light environments produced by the blue LED may have been suitable for this species, both in terms of preferred light intensity and optimal feeding environment. The results presented in this study contribute to a better understanding of the ecology of white-edged rockfish and suggest a selective and efficient use of this species in fisheries.