Body condition, rather than size, predicts risk‐taking and resource holding potential in hatchery reared juvenile lake sturgeon Acipenser fulvescens

Abstract

To test how body size might influence lake sturgeon Acipenser fulvescens anti‐predator behaviour, asymmetrically body‐size‐matched individuals were exposed to conspecific chemical alarm cues with the presence or absence of food. Additionally, to test resource holding potential (RHP), hatchery‐reared juvenile A. fulvescens were asymmetrically (c. 60% mass difference) and symmetrically (c. 3% mass difference) size matched in individual tanks. Results suggest that A. fulvescens of higher body condition, rather than body length or mass, may take greater risks when presented with foraging opportunities and realize a higher RHP. As hatcheries are likely to select individuals of higher body condition, more research is necessary to understand the role body condition may have on behavioural responses and ensuing fitness post‐release.

The lampricide 3-trifluoromethyl-4-nitrophenol causes temporary metabolic disturbances in juvenile lake sturgeon (Acipenser fulvescens): implications for sea lamprey control and fish conservation

“…Young-of-the-year (YOY; total length, 118 ± 1.9 mm; weight, 4.36 ± 0.2 g; N = 32) lake sturgeon were kindly provided by Dr Gary Anderson, Department of Biological Sciences, University of Manitoba. They were the progeny of 4 female and 5 male lake sturgeon, caught on the Winnipeg River (50 o 17′52′′N, 95 o 32′51′′W), from which eggs and sperm were collected by members of the Anderson laboratory in April 2015, fertilized and hatched in mid–late May 2015 ( Bjornson and Anderson, 2018 ). The YOY lake sturgeon were subsequently shipped to Wilfrid Laurier University on 5 December 2015, where they were housed in a multi tank G-HAB aquatic system (Pentair Aquatic Eco-Systems, Apopka, FL, USA) equipped with a five-phase filtration (large particulate, biological, small particulate, carbon and UV) system and kept on recirculation with partial water replacement of 120 l per day.…”

Estimating the potential drivers of dispersal outcomes for juvenile gopher frogs (Rana capito) using agent-based models

“…Predation and dehydration may be partially compensatory sources of mortality. Behavioral demands can result in elevated mortality (e.g., animals in greater need of food or water will engage in riskier behaviors; Bjornson and Anderson, 2018;Houston et al, 1993;McNamara and Houston, 1992). Water deficits, weather constraints, and other needs may constrain antipredator behaviors or increase exposure to predation such as the need to move from suboptimal microclimates when conditions are drier (Rittenhouse et al, 2009).…”

To feed or flee: early life-history behavioural strategies of juvenile lake sturgeon (Acipenser fulvescens) during risk-sensitive foraging

“…Indeed, juvenile lake sturgeon exposed to chronic exposures of AC with PC at ϳ60 dpf had significantly lower mass and Fulton's condition factor than those individuals in the chronic PC with water and control treatments. Such body differences, particularly Fulton's condition factor can influence juvenile lake sturgeon conspecific resource competition and potentially decrease their ability to respond to potential predation threat (Bjornson and Anderson 2018). In addition to physiological responses, juvenile lake sturgeon with chronic predator experience responded behaviorally with significantly less time spent over the no substrate foraging area and more time seeking cover in the gravel interstitial spaces.…”

“…This may suggest that over a gradient of predation pressures, a threshold may be reached where the predation pressures exceed that of the upcoming winter-period pressures, and a shift in risk assessment behaviour during risk-sensitive foraging may occur. However, if high predation pressures continue, then it is likely that overwinter survival may be compromised (Bjornson and Anderson 2018;Deslauriers et al 2018).…”

“…Such overwintering events have large consequences for survival and subsequent year-class strength as that cohort moves into the following year (Post and Evans 1989;Hurst and Conover 2003;Deslauriers et al 2018;Yoon et al 2019). Recent laboratory studies have demonstrated complex behavioural responses in juvenile lake sturgeon (Wishingrad et al 2014b(Wishingrad et al , 2014cFerrari et al 2015;Sloychuk et al 2016;Bjornson and Anderson 2018), but none have attempted to determine the trade-off between foraging and responding to predation threats in juvenile lake sturgeon.…”