Evaluating a light‐louver system for behavioural guidance of age‐0 white sturgeon

Abstract

Water diversions for hydropower and other applications are some of the most disruptive alterations affecting fish populations in lotic systems. Although many different strategies have been developed to reduce lethal encounters with such infrastructure, few studies have evaluated different forms of behavioural guidance concurrently. Here, we combine an LED-based light guidance device (LGD) equipped with adjustable wavelength and strobing output with a reverse-configured louver rack to assess the effectiveness of this two-part behavioural guidance system on downstream movement through a bypass by age-0 white sturgeon (Acipenser transmontanus). Several combinations of LGD and louver settings were tested under both simulated day and night (low light) conditions in a laboratory setting. In the absence of the LGD, louver slat spacings of 10 or 20 cm were most effective at achieving downstream bypasses with greater success rates (~two-fold greater) under night conditions than under day conditions. Incorporating the LGD operating at the most attractive setting (green light strobing at 20 Hz) with the louver spacings of 10 or 20 cm achieved the highest rates of bypass usage (100% and 97%, respectively) under both day and night conditions while the control treatment (no LGD or louver) resulted in the lowest bypass rate (46%) among fish that moved downstream. Collectively, these results demonstrate that complementary cues can enhance the behavioural guidance of fishes and highlight the importance of continuing to explore the use of multiple strategies to mitigate entrainment for high priority fish species.

Behavioural guidance of Chinook salmon smolts: the variable effects of LED spectral wavelength and strobing frequency

“…These processes have been included as one of the reasons for population declines of Chinook salmon in California’s central valley, USA ( Moyle et al ., 2011 ). There is a continued need to create affordable and effective manipulations to water intake structures to reduce fish impingement and entrainment susceptibility without reducing the volume of water extracted and there is evidence that integrative techniques using sensory stimuli, in concert with physical barriers, can enhance fish protection systems ( Nestler and Davidson, 1995 ; Ploskey et al , 1998 ; Popper & Carlson, 1998 ; Sager et al , 2000 ; Perry et al , 2014 ; Ford et al , 2017 ).…”

Coloured LED light as a potential behavioural guidance tool for age 0 and 2 year walleye Sander vitreus

“…First, if walleye generally and consistently avoid light, light stimuli can be used to help limit occurrences of entrainment and impingement for migratory life‐history phases in this species and possibly in congenerics ( e.g ., S. lucioperca ) by using light as a repellent stimulus in areas of elevated hazard. Second, the use of light as an attractant towards desirable areas such as passageways for other species, particularly migratory species (Elvidge et al ., ; Ford et al ., ), is unlikely to have effects beyond repulsion on walleye. Further testing of the LGD as a behavioural guidance tool for walleye is needed to determine behaviour both over longer terms under laboratory conditions and under field conditions.…”

Experimental evaluation of the effect of a light-emitting diode device on Chinook salmon smolt entrainment in a simulated river

“…There is also the need to determine the optimal light intensity for attraction for blue and white light. This has been a successful area of research with age-0 white sturgeon (Acipenser transmontanus), where incorporating the guidance device emitting green light at 20 Hz with a louver has been effective at increasing bypass ratios (Ford et al, 2017(Ford et al, , 2018. Fangue Laboratory and J. Amorocho Hydraulics Laboratory members for all their assistance with fish rearing and flume operation.…”

“…Additionally, differences in light intensity can change the stimulus from being repulsive to attractive (Nemeth & Andersen, 1992) and the required power for this type of lighting is a major implementation cost (Patrick et al, 1985;Brown, 2000;Richards et al, 2007). More recently, therefore, work has begun exploring a range of light frequencies and strobe frequencies of lightemitting diodes (LEDs) for improved performance (Elvidge et al, 2018;Hansen et al, 2018;Ford et al, 2017Ford et al, , 2018.…”

“…Strobing different colored LED's has proven to be effective at behaviorally repelling or attracting a variety of fish species (e.g., Ford et al, 2017Ford et al, , 2018Elvidge et al, 2018). Pacific salmon (Oncorhynchus sp.)…”