Growth potential and habitat requirements of endangered age‐0 pallid sturgeon (Scaphirhynchus albus) in the Missouri River, USA, determined using a individual‐based model framework

Abstract

An individual-based model framework was used to evaluate growth potential of the federally endangered pallid sturgeon (Scaphirhynchus albus) in the Missouri River. The model, developed for age-0 sturgeon, combines information on functional feeding response, bioenergetics and swimming ability to regulate consumption and growth within a virtual foraging arena. Empirical data on water temperature, water velocity and prey density were obtained from three sites in the Missouri River and used as inputs in the model to evaluate hypotheses concerning factors affecting pallid sturgeon growth. The model was also used to evaluate the impacts of environmental heterogeneity and water velocity on individual growth variability, foraging success and dispersal ability. Growth was simulated for a period of 100 days using 100 individuals (first feeding; 19 mm and 0.035 g) per scenario. Higher growth was shown to occur at sites where high densities of Ephemeroptera and Chironomidae larvae occurred throughout the growing season. Highly heterogeneous habitats (i.e., wide range of environmental conditions) and moderate water velocities (0.3 m/s) were also found to positively affect growth rates. The model developed here provides an important management and conservation tool for evaluating growth hypotheses and(or) identifying habitats in the Missouri River that are favourable to age-0 pallid sturgeon growth. K E Y W O R D Sbioenergetics, early-life history, foraging ecology, individual-based model, shallow-water habitat

Differences in macronutrient content of common aquatic macroinvertebrates available as prey for young-of-the-yearScaphirhynchussturgeons in the lower Missouri River

“…Yet, shifts in the availability or consumption of other prey that differ in nutrient content could affect nutrient ingestion by sturgeon or other fish that feed on benthic macroinvertebrates. Recent and ongoing studies have focused on examining abiotic factors that influence habitat use, prey consumption, and condition of YOY Scaphirhynchus sturgeons in the LMOR (Civiello et al 2018;Deslauriers et al 2018;Gemeinhardt et al 2019). However, understanding how other biotic factors may also be influencing recruitment and survival at age-0 still needs to be further understood.…”

Effect of water velocity and temperature on energy use, behaviour and mortality of pallid sturgeon Scaphirhynchus albus larvae

“…Erwin et al, 2018;Sherman et al, 2007). A cooler thermal regime can increase the drift requirements of S. albus larvae by slowing down metabolic processes and the associated development rate (Braaten et al, 2008(Braaten et al, , 2012Deslauriers et al, 2017b;Kynard et al, 2007; this study). Indeed, larvae exhibited lower energy use and growth rate at cooler water temperatures that resulted in a slower behavioural transition from negative to positive rheotaxis (drifting to settling).…”

“…Impoundment of the Missouri River has resulted in a colder thermal regime (Braaten et al ., 2012; Heironimus, 2014; Figure 1) where the effects of cold hypolimnetic water releases below dams can suppress riverine temperatures for over 300 km downriver (DeLonay et al ., 2016; Erwin et al ., 2018; Sherman et al ., 2007). A cooler thermal regime can increase the drift requirements of S. albus larvae by slowing down metabolic processes and the associated development rate (Braaten et al ., 2008, 2012; Deslauriers et al ., 2017b; Kynard et al ., 2007; this study). Indeed, larvae exhibited lower energy use and growth rate at cooler water temperatures that resulted in a slower behavioural transition from negative to positive rheotaxis (drifting to settling).…”

“…The presence of food in fish stomachs, while associated with initiation of exogenous feeding (fry life stage), may not directly relate to when larvae settle out from the drift to the benthos. The behavioural transition from negative to positive rheotaxis likely occurs before first feeding because larvae need to settle to the benthos first to effectively forage on benthic invertebrates as fry (Gisbert & Ruban, 2003;Nguyen & Crocker, 2006;Deslauriers et al, 2017b). Thus, the model proposed by Kynard et al (2007) may overestimate the drift distance required during the larval life stage.…”

Environmental calcium and variation in yolk sac size influence swimming performance in larval lake sturgeon (Acipenser fulvescens)

“…Previous studies have used small swim tunnels to measure the swimming performance of larval fish (Poulsen et al, 2012;Baker et al, 2014;Deslauriers et al, 2017) and other small organisms (Hata et al, 2017). Preliminary tests indicated that A. fulvescens yolk sac larvae do not exhibit consistent positive rheotactic behaviour (i.e.…”