Abstract
Stocking of hatchery-raised fish is an important part of the pallid sturgeon Scaphirhynchus albus recovery program. In the wild, juvenile pallid sturgeon consume primarily aquatic insects, although little is known about specific dietary needs. In hatchery settings, pallid sturgeon are fed commercial diets that are formulated for salmonids. To compare food consumption, growth, and energy status of pallid sturgeon fed artificial or natural diets, we conducted a laboratory study using 24 juvenile pallid sturgeon (initial fork length 153–236 mm). Pallid sturgeon were fed a daily ration of either commercial pellets (1 mm, slow sinking; 45% protein, 19% fat) or chironomid larvae for 5 wk. Natural-fed pallid sturgeon exhibited a greater specific growth rate (2.12% d−1) than pellet-fed fish (0.06% d−1). Similarly, relative condition was greater for natural-fed sturgeon (Kn = 1.11) than that observed for pellet-fed fish (Kn = 0.87). In contrast, the hepatosomatic index was significantly higher in pellet-fed fish (2.5%), indicating a high lipid diet compared with natural-fed sturgeon (1.4%). Given the importance of natural diets to fish digestion and growth, it is suggested that a more holistic approach be applied in the development of a practical diet for pallid sturgeon that incorporates attributes of natural prey.
Introduction
Sturgeon (Acipenseriformes) are considered one of the most endangered groups of fishes in the world and are considered species of concern throughout much of their range (Birstein 1993; Secor et al. 2002). Overharvest, habitat loss, pollution, and habitat fragmentation (i.e., migration barriers) have been attributed to the decline of sturgeon species worldwide (Birstein et al. 1997). Efforts to enhance sturgeon populations increasingly rely on captive propagation and stocking programs to aid in their recovery (Williamson 2001; Chebanov et al. 2002; Secor et al. 2002; Smith et al. 2002).
The pallid sturgeon Scaphirhynchus albus is a federally endangered species pursuant to the U.S. Endangered Species Act (ESA 1973, as amended; 55 FR 36641, September 6, 1990) that occurs in the Missouri and lower Mississippi rivers (Dryer and Sandoval 1993). Recovery efforts for pallid sturgeon are focused on habitat restoration, population assessment, captive propagation, and a comprehensive sturgeon research program (Dryer and Sandoval 1993). Hatchery propagation and subsequent stocking of pallid sturgeon has served an important role in recovery efforts, particularly in the upper Missouri River basin where there has been little evidence of natural reproduction (Bergman et al. 2008).
Hatchery-reared pallid sturgeon larvae (18–25 mm) are often fed a diet of natural prey (e.g., Copepoda, Euphausiacea, or Artemia) before being transitioned to an artificial diet formulated for salmonid fishes (J. Powell, personal communication; Meyer 2011). Juvenile pallid sturgeon are then grown to a length of about 250 mm fork length (FL) before stocking in the Missouri River. Sturgeon smaller than 250 mm are not usually stocked because they are difficult to tag using passive integrated transponder tags. Producing pallid sturgeon to the desired stocking length can take 10–15 mo, nearly twice as long as most other stocked fish species (Hart et al. 1996; Summerfelt et al. 1996). In addition to being able to individually tag stocked fish, a larger size at stocking can increase poststocking survival. Steffensen et al. (2010) reported apparent survival of 0.048 for pallid sturgeon stocked at age-0, vs. apparent survival of 0.4 for age-1 and 0.931 for age-1+ pallid sturgeon stocked into the lower Missouri River. Although stocking larger fish can increase poststocking survival, it also leads to an increase in production costs.
Comparative studies have shown that growth and survival are often greater for fish fed natural diets compared with artificial diets (Kirk and Howell 1972; Buddington and Doroshov 1984; Lindberg and Doroshov 1986; Kerdchuen and Legendre 1994; Barrows and Hardy 2001). Indeed, among sturgeons, studies have shown that young fish generally grow and survive better when fed natural diets compared with artificial diets (Table 1). Thus, natural diets represent important “controls” during the evaluation of more practical (i.e., artificial) diets for culture applications (Buddington and Doroshov 1984).
Specific growth rate (SGR) and survival of sturgeons fed either natural (N) or artificial (A) diets in controlled environments as reported in published literature. Artificial diets that consisted of commercial trout diets are shown as CTD, whereas those specifically formulated by the researchers are labeled FORM. n.d. indicates “not determined.” Details of natural and artificial diets are summarized in the referenced citation.

Growth and conversion efficiency (CE) for fish has been linked to the composition and activity of digestive enzymes that are known to vary among fishes depending on the types of prey they consume (Jobling 1995; Horn 1998; Kolkovski 2001). In the wild, juvenile pallid sturgeon primarily consume aquatic invertebrates, especially Chironomidae and Ephemeroptera taxa (Wanner et al. 2007; Grohs et al. 2009). Because insectivorous fishes produce greater amounts of chitinase to break down exoskeletons (Jobling 1995), they may be better able to process invertebrate diets over fish meal-based diets commonly used in sturgeon culture. Understanding the differences between natural and artificial diets on pallid sturgeon growth, condition, and energy storage has important implications for the propagation program and development of a practical diet formulation. In this study, we compare growth, condition, and energy status of juvenile pallid sturgeon fed a natural diet of commercially available Chironomidae larvae with that of fish fed a commercial trout diet over a 5-wk period.
Methods
Juvenile pallid sturgeon (n = 24; mean = 20.4 g; 95% CI 19.4–21.5 g) were obtained from the U.S. Fish and Wildlife Service Garrison Dam National Fish Hatchery, Riverdale, North Dakota on April 14, 2010. Study animals were randomly selected from a mixed pool of family lots. Fish were placed individually into 24 insulated, 114-L glass aquaria to measure individual food consumption and growth. All 24 aquaria were connected to the same recirculating system that included a biofiltration tank and a sand filter. Water temperature was monitored hourly in the recirculating system using temperature loggers (n = 4; Tidbit, Onset Corp., Bourne MA); mean daily water temperature during the 5-wk feeding trial was 22.1°C (SE = 0.2). Twelve fish were chosen at random and slowly, over approximately 8 to 10 d, switched from an artificial diet (1-mm sinking feed; Nelsons and Sons, Silver Cup, Appendix A) to a diet of Chironomidae larvae. Frozen chironomids were obtained from a commercial dealer (Hikari USA, Hayward, CA) and thawed before being offered to fish. A majority of thawed chironomid larvae added to each tank sank to the bottom, where pallid sturgeon can effectively feed on this diet item. Pallid sturgeon were then fed solely the artificial diet or chironomids for approximately 2 wk before starting feeding trials.
Feeding and growth
We measured feeding and growth of juvenile pallid sturgeon fed the artificial or chironomid diet for 37 d. Fish assigned to each feeding group were fed a preweighed, ad libitum ration of the respective diet twice a day, with uneaten food recovered daily to measure food consumption. For the natural diet, hereafter referred to as chironomids, we blotted and weighed food to the nearest 0.1 g. The artificial diet, hereafter referred to as pellets, was air dried for at least 24 h after siphoning and weighed to the nearest 0.1 g. Daily food consumption (g/d) was calculated for each fish as the difference between the amount of food fed and that recovered from the aquaria 24 h later. To account for leaching and residual breakdown of food items that might lead to overestimation of food consumption, we measured recovery of chironomids and pellets in tanks without fish. Five grams of each diet were introduced into fishless aquaria (n = 3/diet) and recovered from the tank 24 hs later. We calculated a recovery ratio as the amount of food recovered divided by the initial amount introduced, and averaged these values for each diet type. Mean recovery rate for chironomids was 68.4% compared with 63.3 % for pellets.
The energy content (kJ/g) of each diet was determined using bomb calorimetry (1108 oxygen bomb calorimeter, Parr Instrument Co., Moline, IL). We oven dried (60°C) five samples of each diet to a constant weight and calculated the ratio of dry to wet weight to adjust for differences in water content. Daily food consumption (g/d) was multiplied by energy density of the respective diet and expressed as kJ/d.
We measured length and weight of fish at 7-d intervals. Fish were measured for FL (mm) and weighed to the nearest 0.1 g. Specific growth rate (SGR, % body wt/d) was calculated as
where W0 is initial weight and Wt is the final weight of fish (in g). Total growth and total food consumption for each fish were used to calculate CE as
Body condition and energy status
We calculated relative condition factor (Kn; LeCren 1951) for pallid sturgeon fed chironomids, hereafter referred to as natural-fed, or pellets, hereafter referred to as pellet-fed, at the end of the 5-wk feeding trial using the equation
where W is the observed weight (in g wet weight) and W′ is predicted weight for a pallid sturgeon using the equation
where L is fork length in mm (Keenlyne and Evenson 1993). After completion of the feeding trials, all fish were euthanized using an overdose (approximately 0.5 g/L) of MS-222 (Finquel®, Argent Chemical Laboratories, Redmond, WA). Fish were weighed wet to the nearest 0.1 g, and the liver was excised and weighed wet to the nearest 0.1 g. We calculated the hepatosomatic index (HSI) for each fish as
where LW represents liver weight and BW is body weight (in g). To determine gross energy density (kJ/g wet weight), six pallid sturgeon were randomly selected from each diet group. Fish were dried to a constant weight, ground to a fine powder, and then pelletized (1- to 1.5-g samples) before combustion in an oxygen bomb calorimeter (Parr Instrument).
Data analysis
Results
Feeding and growth
Energy density of chironomids averaged 2.46 kJ/g and was significantly lower than mean energy density for pellets: 19.96 kJ/g (df = 6, t = −48.2, P < 0.0001). Mean total food consumption (g) was greater for sturgeon fed chironomids. Moreover, total food consumption was less variable for chironomid-fed sturgeon (coefficient of variation [CV] = 19%) than pellet-fed fish (CV = 46%). Although consumption of chironomids (g) was greater than that for pellets, total energy (kJ) consumed by pellet-fed sturgeon was greater than that for natural-fed fish (Table 2).
Mean total food consumption by juvenile pallid sturgeon Scaphirhynchus albus (initial size, 18.6–22.2 g) reared at 22°C for 37 d at South Dakota State University in Brookings, South Dakota, from May 4 to June 9, 2010. Total consumption for fish fed a natural or artificial diet is expressed by weight (g) and energy (kJ). Values in parentheses are 95% confidence limits.

Mortality rate was 0% for natural-fed pallid sturgeon and 8.3% (n = 1) for pellet-fed fish. Mean initial weight of pallid sturgeon after acclimation to a new diet was similar between the chironomid-fed fish at 18.6 g and pellet-fed fish at 22.2 g (df = 22, t = 1.81, P = 0.08; Figure 1). By the end of the feeding trial, mean weight of natural-fed fish (42.4 g) was nearly twice that of pellet-fed fish (24.2 g; Figure 1). Chironomid-fed fish gained an average of 0.64 g/d, whereas pellet-fed fish had an average daily growth of 0.05 g/d. Similarly, chironomid-fed fish grew an average of 1.2 mm/d, whereas pellet-fed fish grew an average of only 0.17 mm/d over the 5-wk feeding trial. As a result, specific growth rate was significantly greater for pallid sturgeon fed chironomids (Table 3).
Mean weight (g) of chironomid-fed (open circles) or pellet-fed (solid squares) hatchery-reared juvenile pallid sturgeon Scaphirhynchus albus during a 5-wk feeding trial conducted at South Dakota State University in Brookings, South Dakota, from May 4 to June 9, 2010. Vertical bars represent 95% confidence limits. Note: Data points on x-axis are offset slightly for clarity.
Mean weight (g) of chironomid-fed (open circles) or pellet-fed (solid squares) hatchery-reared juvenile pallid sturgeon Scaphirhynchus albus during a 5-wk feeding trial conducted at South Dakota State University in Brookings, South Dakota, from May 4 to June 9, 2010. Vertical bars represent 95% confidence limits. Note: Data points on x-axis are offset slightly for clarity.
Mean specific growth rate, conversion efficiency, gross energy, relative condition, and hepatosomatic index for hatchery-reared juvenile pallid sturgeon Scaphirhynchus albus fed a natural (Chironomidae larvae) or artificial (commercial trout feed) diet at South Dakota State University in Brookings, South Dakota, from May 4 to June 9, 2010. Values in parentheses represent 1 SE. P-values from t-tests were adjusted to control for family-wise error rate using the stepdown Bonferroni correction.

Differences in feeding and growth rate were also reflected in conversion efficiency for pallid sturgeon. Conversion efficiency for chironomid-fed pallid sturgeon was generally higher than that for fish fed pellets (Table 3). As with feeding and growth rates, CE for chironomid-fed fish was also notably less variable (CV = 9%) than for pellet-fed fish (CV = 97%).
Body condition and energy status
Mean energy density of pallid sturgeon was similar between diet treatments (Table 3). Energy density of pallid sturgeon fed chironomids ranged from 2.59 to 4.07 kJ/g, whereas energy density of fish fed pellets ranged from 1.88 to 4.53 kJ/g. Despite similar energy density, mean condition (Kn) of chironomid-fed pallid sturgeon was greater than that observed for pellet-fed fish (Table 3). In contrast, pallid sturgeon fed chironomids had a lower HSI value than those fed pellets (Table 3). However, similar to other measures, the HSI was more variable (CV = 23%) for fish fed pellets than for those fed chironomids (CV = 10%).
Discussion
Pallid sturgeon fed a natural diet of chironomid larvae grew faster, had higher body condition, and lower HSI values than fish fed an artificial diet formulated primarily for salmonids. Natural diets can outperform commercial diets in certain cultured fish species (Lindberg and Doroshov 1986; Barrows and Hardy 2001; Hodgins et al. 2014). More specifically, natural diets resulted in better growth than formulated diets in other cultured sturgeon species such as the Chinese sturgeon Acipenser sinensis (Xiao et al. 1999), beluga sturgeon Huso huso, and Persian sturgeon Acipenser persicus (Ebrahimi and Zare 2006). Although energy density of the pellet diet used in this study was eight times higher than the chironomid diet, energy density of pallid sturgeon fed each respective diet item was similar, indicating increased energy assimilation of the natural diet. Our results were similar to other laboratory studies comparing natural and artificial diets. Hodgins et al. (2014) had similar results where black carp Mylopharyngodon piceus were fed a pellet diet with high energy density compared with a diet of live snails. Specific growth rate of black carp fed a live or artificial diet were similar, despite differences in energy consumption in the two groups (Hodgins et al. 2014).
Dietary protein:energy ratios can have an important influence on fish nutrition and growth (op cit; Tibbetts et al. 2005). Although not quantified in our study, recent work with semipurified diets showed that growth rate of juvenile pallid sturgeon was similar over a wide range of protein:energy ratios (79–147 mg/kcal; Kittel and Small 2014). Conversely, growth rate of pallid sturgeon was positively related to gross energy content (J/g) of semipurified diets (Kittel and Small 2014). In our study, gross energy content of consumed food was inversely associated with pallid sturgeon growth, implying that to maximize growth rate of pallid sturgeon, factors other than gross energy content of the diet need to be considered. Although formulated diets are fortified with nutrients and vitamins, digestibility and uptake may differ among life stages and species (Kolkovski 2001; Furné et al. 2005). Nutrient transport systems in the digestive tract have been linked to the type of prey that fish eat (Jobling 1995; Horn 1998; Furné et al. 2005). Insectivorous fishes, for example, have relatively high levels of chitinase to break down exoskeletons, whereas piscivorous fishes have greater levels of pepsin to break down proteins (Jobling 1995). Incomplete digestion of artificial diets due to incompatible digestive enzymes or improper nutrient transport may contribute to suboptimal performance of pallid sturgeon reared on pelleted food as demonstrated in this study by low SGR and low Kn.
Our observations, derived from comparing natural and artificial diets, underscore the importance of the holistic approach in developing practical diet formulations for pallid sturgeon. The absence of information on natural diets, for example, does not preclude our ability to identify the “best” formulation from an inferior suite of prepared diets. However, Kolkovski (2001) points out in a review of digestive enzymes in juvenile fishes that such approaches overlook important autoecological adaptations and the role that exogenous factors (i.e., digestive enzymes of prey) play in fish nutrition. The efficiency of digestion not only depends on the food that is ingested, but also the physiological capacity of fish to digest the nutrients in a food item (Asgari et al. 2013). Kolkovski (2001) proposed additional mechanisms by which natural foods promote digestion, nutrient utilization, and growth rate of fishes. It has been suggested that natural (live) food items can “donate” their digestive enzymes to juvenile fishes, thereby contributing an exogenous component to the diet not available in formulated foods. Similarly, digestive enzymes of natural diets may activate zymogens (inactive enzyme precursor) in the gut of the common carp Cyprinus carpio, and rainbow trout Oncorhynchus mykiss, inducing an increase in endogenous protease (i.e., trypsin) secretion that facilitates protein assimilation and absorption (Pedersen and Hjelmeland 1988; Kolkovski 2001; Furné et al. 2005). Given the importance of natural diets to fish digestion and growth, diet formulation is more complicated than comparing different combinations of nutrients, and a more holistic approach, such as matching digestive physiology and nutritional requirements of a species, can aid in the development of practical fish diets (Kolkovski 2001; Asgari et al. 2013).
Cultured fishes often have high levels of liver lipids, especially those on formulated diets (Serrano et al. 1992; Brown et al. 1993; Flood et al. 1996; Nanton et al. 2001). Although lipids are an important form of energy for fish, an excess of lipids in the diet may be detrimental to fish health. The liver is important for lipid and carbohydrate storage, gonad development, immune function, and bile production, and it acts as a primary site for biotransformation of chemicals such as nutrients, steroids, and contaminants (Bruslé and Gonzàlez i Anadon 1996; Flood et al. 1996). Artificial diets with excessive lipids can cause liver damage (hepatic lipoid disease) in some cultured fish species, and substantial accumulation of lipids in the liver may be responsible for declines in health or suboptimal growth (Flood et al. 1996; Tibbetts et al. 2005). Cobia Rachycentron canadum fed diets with 5 or 15% dietary lipid levels had greater growth rates than individuals fed a diet with 25% lipid (Wang et al. 2005). Because we did not examine liver lipid or liver enzymes in pallid sturgeon, it is unknown whether liver function was impaired in fish fed the artificial diet. Liver tissue is particularly sensitive to diet quality and quantity (Asgari et al. 2014). For example, changes in lipid deposition in the liver of beluga sturgeon was attributed to the nature of the dietary lipids (Asgari et al. 2014). Elevated HSI values can indicate inefficient utilization of dietary energy (Morias et al. 2001; Tibbetts et al. 2005), and may explain why pallid sturgeon fed an artificial diet had slower growth and lower conversion efficiency than those fed chironomids.
Rearing density can influence feeding and growth rate of fishes, particularly at high stocking densities. Although stocking density was low (1 fish/tank) in our study, it was identical for both diet treatments. We have no reason to suspect that growth rate varies differentially with rearing density of fish fed different diets. By having only one individual per tank, no feeding hierarchies developed, and all fish had equal access to food through the duration of the study. Dominance hierarchies can develop in tanks with high rearing densities, leading to substantial individual variation in size (Mohseni et al. 2006). In addition, studies with other juvenile sturgeons have shown similar feeding and growth rates across a wide range of rearing densities. Juvenile lake sturgeon fed chironomids and reared at densities from 100 to 450 fish/m3 showed similar growth rates (Fajfer et al. 1999). Similarly, juvenile Russian sturgeon reared at densities of 8 or 12 fish/m3 had similar growth and feed conversion rates (Çelikkale et al. 2005). Finally, larval white sturgeon reared at densities of 4,545 to 18,181/m3 did not differ in growth rate after 80 d of rearing (Monaco et al. 1981).
Insufficient knowledge of the dietary needs of pallid sturgeon could affect recovery efforts by population augmentation. Many of the populations that exist (specifically in the upper Missouri River) consist of a few old individuals and have no natural recruitment (Gerrity 2005; Steffensen et al. 2015). Therefore, survival and growth of hatchery-reared juvenile pallid sturgeon are essential to recovery of the species (Gerrity 2005; Steffensen et al. 2015). Although stocked pallid sturgeon exhibit reasonably good survival rates ranging from 5 (age 0) to 68% (age 1; Steffensen et al. 2010), recent evidence has shown that condition of pallid sturgeon in the Missouri River and the frequency of females in reproductive condition has declined significantly over the last 12 y (Steffensen and Mestl 2016). Although reasons for the decline in body condition are not known, they were not significantly correlated with population size or river discharge (Steffensen and Mestl 2016).
Outside of laboratory feeding trials such as ours, the influence of natural prey composition and abundance on pallid sturgeon condition remains poorly understood. Several studies have found that feeding, growth, and condition of released fish species were correlated to time at large in a natural environment, indicating that it may take a considerable amount of time for hatchery-reared fish to acclimate to a natural environment (Brown and Laland 2001; Ireland et al. 2002; Sparrevohn and Støttrup 2007). Producing fish that are morphologically, behaviorally, and physiologically similar to those in the wild may enhance the success of conservation aquaculture programs (Brown and Day 2002).
Because pellet-fed pallid sturgeon cost about 80% less to rear than natural-fed fish, it is probably not economically feasible to rear pallid sturgeon entirely on chironomids. However, it may be beneficial to alter feeding regimes from an artificial to a natural diet before stocking. Although our study only lasted 5 wk, we observed greater conversion efficiencies, growth rates, and condition factors by using a natural diet vs. a commercial salmon diet. Use of a natural diet may increase growth during the last few weeks of hatchery rearing for pallid sturgeon, and feeding fish a natural prey item for only a short duration (immediately before stocking) may abet the increased cost of feed. Acclimating pallid sturgeon to natural prey items before stocking may also be advantageous for greater poststocking growth and body condition. Acclimating hatchery-reared fish to natural-type food items can improve foraging efficiency, and may only take a few repetitions to accomplish (Brown and Day 2002; Brown and Laland 2002). Moreover, if current habitat conditions and river management in the Missouri River are limiting growth and condition of pallid sturgeon, then stocking fewer fish in better condition may be the most practical biological and economical alternatives to sustaining a healthy pallid sturgeon population until habitat and river management options are improved for pallid sturgeon.
Supplemental Material
Please note: The Journal of Fish and Wildlife Management is not responsible for the content or functionality of any supplemental material. Queries should be directed to the corresponding author for the article.
Data S1. Diet type (pellet; Silver Cup 1-mm slow-sinking feed, or frozen chironomids), length (mm), weight (g), and relative condition factor (Kn) of hatchery-reared juvenile pallid sturgeon Scaphirhynchus albus fed a natural (Chironomidae larvae) or artificial (commercial trout feed) diet at South Dakota State University in Brookings, South Dakota, from May 4 to June 9, 2010.
Found at DOI: 10.3996/082015-JFWM-076.s1; (8 KB XLSX).
Data S2. Diet type (pellet; Silver Cup 1-mm slow-sinking feed, or frozen chironomids), tank number, body weight, liver weight, and hepatosomatic index (liver weight/body weight × 100) of hatchery-reared juvenile pallid sturgeon Scaphirhynchus albus fed a natural (Chironomidae larvae) or artificial (commercial trout feed) diet at South Dakota State University in Brookings, South Dakota, from May 4 to June 9, 2010.
Found at DOI: 10.3996/082015-JFWM-076.s2; (8 KB XLSX).
Data S3. Diet type (pellet; Silver Cup 1-mm slow-sinking feed, or frozen chironomids), fish number, and measured energy density (kJ/g wet weight of fish) of hatchery-reared juvenile pallid sturgeon Scaphirhynchus albus fed a natural (Chironomidae larvae) or artificial (commercial trout feed) diet at South Dakota State University in Brookings, South Dakota, from May 4 to June 9, 2010.
Found at DOI: 10.3996/082015-JFWM-076.s3; (8 KB XLSX).
Data S4. Food type (pellet; Silver Cup 1-mm slow-sinking feed, or frozen chironomids) and measured energy density of food type (kJ/g wet weight of food) of two diets fed to hatchery-reared juvenile pallid sturgeon Scaphirhynchus albus at South Dakota State University in Brookings, South Dakota, from May 4 to June 9, 2010.
Found at DOI: 10.3996/082015-JFWM-076.s4; (8 KB XLSX).
Data S5. Ingredients and guaranteed analysis of Nelson's Silver Cup slow-sinking feed.
Found at DOI: 10.3996/082015-JFWM-076.s5; (13 KB DOC).
Reference S1. Bergman, HL, Boetler AM, Parady K, Flemming C, Keevin T, Latka DC, Korschgen C, Galat DL, Hill T, Jordan G, Krentz S, Nelson-Stastny W, Olson M, Mestl GE, Rouse K, Berkley J. 2008. Research needs and management strategies for Pallid Sturgeon recovery. Proceedings of 31 July–2 August 2007 workshop, St Louis, Missouri. Final report to the U.S. Army Corps of Engineers. Laramie, Wyoming: William D. Ruckelshaus Institute of Environment and Natural Resources, University of Wyoming.
Found at DOI: 10.3996/082015-JFWM-076.s6; (2,952 KB PDF).
Reference S2. Dryer MP, Sandoval AJ. 1993. Recovery plan for the pallid sturgeon (Scaphirhynchus albus). Bismarck, North Dakota: U.S. Fish and Wildlife Service.
Found at DOI: 10.3996/082015-JFWM-076.s7; (3,484 KB PDF).
Reference S3. Meyer HA 2011. Influence of diet and environmental variation on physiological responses of juvenile pallid sturgeon (Scaphirhynchus albus). Master's thesis. Brookings: South Dakota State University.
Found at DOI: 10.3996/082015-JFWM-076.s8; (367 KB PDF).
Acknowledgments
This manuscript is dedicated to the memory of our friend and coauthor, Dr. Robert Klumb. We thank R. Holm at Garrison Dam National Fish Hatchery (Riverdale, North Dakota) for providing pallid sturgeon for this study. We also thank M. Semrow and B. VanDeHey for assistance with data collection, D. James, M. Fincel, M. Greiner, M. Thul, and H. Calkins and three anonymous reviewers for providing helpful comments on a previous version of this manuscript, and South Dakota State University staff for laboratory support. All animals used in this study were reared according to animal use and care guidelines established by South Dakota State University (Animal Welfare Assurance no. A3958-01). The South Dakota Cooperative Fish & Wildlife Research Unit is jointly sponsored by the U.S. Geological Survey, South Dakota State University, South Dakota Department of Game, Fish & Parks, the Wildlife Management Institute, and the U.S. Fish & Wildlife Service. Funding for this project was provided by the U.S. Army Corps of Engineers (RFP W9128F-09-R-0030).
Any use of trade names is for descriptive purposes only and does not imply endorsement by the U.S. Government.
References
Author notes
Citation: Meyer HA, Chipps SR, Graeb BDS, Klumb RA. 2016. Growth, food consumption, and energy status of juvenile pallid sturgeon fed natural or artificial diets. Journal of Fish and Wildlife Management 7(2):388–396; e1944-687X. doi: 10.3996/082015-JFWM-076
The findings and conclusions in this article are those of the author(s) and do not necessarily represent the views of the U.S. Fish and Wildlife Service.