Behavioural responses of krill and cod to artificial light in laboratory experiments

Abstract

Most fishes and crustaceans respond to light, and artificial light sources may therefore be an efficient stimulus to manipulate behaviours in aquatic animals. It has been hypothesised that the catch efficiency of pots could be increased if prey, for example krill, can be attracted into the pots providing a visual stimulus and a source of live bait. To find which light characteristics are most attractive to krill, we tested the effects of light intensity and wavelength composition on Northern krill’s (Meganyctiphanes norvegica) behavioural response to an artificial light source. The most attractive individual wavelength was 530 nm (green light), while broadband (425–750 nm) white light was an equally attractive light source. The intensity of the emitted light did not appear to have a direct effect on attraction to the light source, however it did significantly increase swimming activity among the observed krill. The most promising light stimuli for krill were tested to determine whether they would have a repulsive or attractive effect on cod (Gadus morhua); These light stimuli appeared to have a slightly repulsive, but non-significant, effect on cod. However, we suggest that a swarm of krill attracted to an artificial light source may produce a more effective visual stimulus to foraging cod.

The Right Light: Tiger Salamander Capture Rates and Spectral Sensitivity

“…Once the initial salamander was captured, other stimuli, perhaps motion from previously captured salamanders, may have affected the numbers of salamanders present in successful traps. Many animals are attracted to motion from potential prey or mates and the stimulus of motion, when present, may affect behavior more than color or light stimuli (Schaerer and Neumeyer 1996, Utne‐Palm et al 2017). However, initial capture of salamanders (trap success) was biased strongly toward a particular color, orange, despite the brighter luminance and greater total quantum catches of yellow and green glow sticks.…”

“…The magnitude of attraction of teleost fish to light sources can vary based on light intensity or color of the lights (Nemeth and Andersen 1992, Marchesan et al 2005, Ford et al 2018, Wei et al 2019). Although many studies have investigated preferences of teleost fish toward light sources, few studies have compared behaviors with variation in intensity and wavelength of these light sources (Marchesan et al 2005, Utne‐Palm et al 2017, Ford et al 2018, Hansen et al 2018). Further, little is known about what light intensities and colors best attract nonfisheries species (but see Cruz et al 2018 for turtles, Poot et al 2008 for migrating birds).…”

Application of Luminescent Netting in Traps to Improve the Catchability of the Snow Crab Chionoecetes opilio

“…; Utne‐Palm et al. ). In the case of snow crabs, much remains unknown about how and why light increases the CPUE of traps.…”

“…; Utne‐Palm et al. ). To our knowledge, very little is known about how snow crabs see and perceive light, or about the structure, function, or evolution of their eyes.…”

“…However, in some cases the mechanism may be more complicated. For example, evidence suggests that Atlantic Cod are not necessarily attracted to artificial light, but instead can be enticed to enter a trap in pursuit of prey, which are themselves attracted by the light Utne-Palm et al 2018). In the case of snow crabs, much remains unknown about how and why light increases the CPUE of traps.…”