Mechanisms of Phototaxis in American Crayfish, Procambarus clarkii (Girard, 1852) Following Different Methods of Trapping

摘要

The phototactic behavior of the American crayfish Procambarus clarkii was investigated in aquaria and a large tank to determine their sensitivity thresholds to light and possible harvesting applications. Adult and juvenile crayfish were found to be positively phototactic and their attraction to light was highest at an intensity of 1,290 lx. Conversely, post-embryonic crayfish were negatively phototactic and moved away from the light source at intensities higher than 111 lx. Fishing trials using traps with four open funnel entrances under lighted and dimmed lamps, fish baited and non-baited treatments tested the application of flapping with lamps as an alternative harvesting method. Results showed that traps with lighted and dimmed lamps captured similar numbers of crayfish, that in some cases they catch significantly more crayfish than non-baited traps, but that their catching performance was lower than fish baited traps. Possible applications of this novel luring method are further discussed, as well as its implications in eradication programs and harvest from aquaculture ponds.