Brian D. S. Graeb

Fish Size and Prey Availability Affect Growth, Survival, Prey Selection, and Foraging Behavior of Larval Yellow Perch

Abstract Zooplankton availability is strongly linked with the growth, survival, and ultimately recruitment of fish during their early life history. We examined how different types of zooplankton affected the growth, survival, and prey selection of larval yellow perch Perca flavescens in a series of laboratory experiments. The growth and survival of newly hatched (5–7-mm) to 12-mm yellow perch larvae was greatest when feeding on adult copepods and copepod nauplii. The growth and survival of yellow perch larvae longer than 12 mm was greatest when feeding on adult copepods and small cladocerans. Prey selection patterns closely followed trends in growth and survival; smaller larvae positively selected adult and naupliar copepods, whereas larger larvae selected adult copepods and small cladocerans. Foraging behavior experiments conducted with larvae longer than 12 mm revealed that these fish derived similar energetic gains when feeding solely on adult copepods and small cladocerans. The pathway to this energet...

Ontogenetic Changes in Prey Preference and Foraging Ability of Yellow Perch: Insights Based on Relative Energetic Return of Prey

Abstract Ontogenetic diet shifts are an important component of the early life history of many fishes. Successfully shifting diets affects not only individuals but also populations and communities. We experimentally quantified prey selection and feeding behavior of age-0 yellow perch Perca flavescens to determine the sizes at which diet shifts occur and identify potential mechanisms driving these shifts. Yellow perch were provided three prey types (zooplankton, benthic invertebrates, and fish) at high- and low-density combinations. Small yellow perch (20 mm total length [TL]) positively selected zooplankton, but intermediate-sized fish (40 and 60 mm TL) shifted to benthic invertebrates. At 80 mm TL, yellow perch positively selected benthic invertebrate and fish prey, indicating the onset of piscivory. Relative densities of prey items did not influence prey selection patterns. Diet shifts from zooplankton to benthic invertebrates to fish prey were supported by an increased energetic gain and decreased forag...

Influence of the Moran Effect on Spatiotemporal Synchrony in Common Carp Recruitment

Abstract Climatic variation and dispersal are two primary factors thought to induce recruitment synchrony in fish populations. We hypothesized that climate factors correlated across a broad geographical scale (i.e., the Moran effect) would induce synchrony in recruitment for common carp Cyprinus carpio among 18 glacial lakes across a 175-km2 area in eastern South Dakota. Cross-correlation analysis indicated that common carp population fluctuations were highly synchronous among lakes. To evaluate the influence of the Moran effect on recruitment, we examined several candidate models using an information-theoretic approach. The model with the most support included the interaction of temperature, precipitation, and wind during the open-water period. This model indicated that the effects of any one of these climate variables on recruitment strength depended on the level of each of the other variables in any given year. Our results suggest that common carp populations in the Midwestern United States exhibit syn...

Ecological Consequences of Swim Bladder Noninflation for Larval Yellow Perch

Abstract Swim bladder inflation is a fundamental developmental step during the larval stage of many fishes. Although the physiological mechanisms of swim bladder inflation are well documented, the ecological costs of noninflation are poorly understood. If high proportions of newly hatched fish larvae fail to inflate their swim bladders and swim bladder noninflation negatively affects individual survival probability, the population-level effects could be dramatic. To determine whether fish larvae without inflated swim bladders perform differently than their conspecifics with inflated swim bladders, we compared growth rate, feeding selectivity and efficiency, susceptibility to predation, oxygen consumption, and starvation mortality of two size-classes of larval yellow perch Perca flavescens with and without inflated swim bladders in a series of experiments. In the laboratory, growth rates of yellow perch with uninflated swim bladders were less than those for fish with inflated swim bladders, and fish with i...

Age-Structured Assessment of Walleyes, Saugers, and Naturally Produced Hybrids in Three Missouri River Reservoirs

Abstract Walleye Sander vitreus and sauger Sander canadensis naturally hybridize in many populations, but the factors influencing the recruitment of hybrids are unknown. We determined relative year-class strength for 1,454 saugers, walleyes, and naturally produced hybrids from three Missouri River reservoirs. Hybridization rates varied from 4% in Lakes Sharpe and Francis Case to 21% in Lewis and Clark Lake. Hybrids comprised multiple year-classes in each system, indicating that hybridization does not occur in erratic pulses but at a consistent low-level recruitment rate. The year-class strength of hybrids was not correlated with that of either walleyes or saugers. Our models suggest that higher than average recruitment of walleyes, saugers, and hybrids can be expected during years with warmer spring and early summer water temperatures in Lake Sharpe and Lewis and Clark Lake and during years when inflow (from main-stem discharge for hybrids and tributary inputs for saugers and walleyes) is reduced in Lewis...

Precision and Bias of Cleithra and Sagittal Otoliths Used to Estimate Ages of Northern Pike

Abstract Cleithra are thought to accurately record age information and produce the most reliable age estimates relative to other calcified structures (e.g., scales) for long-lived species of Esocid...

Walleye Sander vitreus and smallmouth bass Micropterus dolomieu interactions: an historic stable-isotope analysis approach

The carbon (δ(13) C) and nitrogen (δ(15) N) values of Sander vitreus scales differed pre and post-introduction in treatment lakes among years following the introduction of Micropterus dolomieu. No difference of δ(13) C and δ(15) N in S. vitreus scales was found in control lakes where M. dolomieu were not introduced. In treatment lakes, S. vitreus δ(15) N increased and δ(13) C decreased. No relationship was found between S. vitreus and M. dolomieu abundance in the two treatment lakes. Size structure of S. vitreus and M. dolomieu was negatively correlated and condition of the two species was positively correlated. Although S. vitreus feeding habits may have changed in the treatment lakes after M. dolomieu introductions, evidence suggests that fitness-related factors (i.e. abundance and condition) of S. vitreus remained unchanged, indicating S. vitreus and M. dolomieu may coexist where M. dolomieu have been introduced.

Exploring spatial distributions of larval yellow perch Perca flavescens, bluegill Lepomis macrochirus and their prey in relation to wind

The objectives of the present study were to determine if spatial differences existed between zooplankton, larval yellow perch Perca flavescens and bluegill Lepomis macrochirus (<13 mm total length, L(T)) in Pelican Lake (332 ha), NE, U.S.A. It was hypothesized that wind could act as a transport mechanism for larval fishes in this shallow lake, because strong winds are common at this geographic location. Potential spatial differences were explored, relating to zooplankton densities, size structure and densities of larval P. flavescens and L. macrochirus. Density differences (east v. west side of the lake) were detected for small- (two occasions), medium- (two occasions) and large-sized (one occasion) L. macrochirus larvae. No density differences were detected for small P. flavescens larvae; however, densities of medium- and large-sized P. flavescens were each higher on the west side of the lake on two occasions. There was no evidence that larval P. flavescens and L. macrochirus distributions were related to wind because they were not associated with large wind events. Likewise, large wind event days did not result in any detectable spatial differences of larval P. flavescens and L. macrochirus densities. There appeared to be no spatial mismatch between larval densities and associated prey in the years examined. Thus, wind was not apparently an influential mechanism for zooplankton and larval P. flavescens and L. macrochirus transport within Pelican Lake, and spatial differences in density may instead be related to vegetation and habitat complexities or spawning locations within this shallow lake.

Stocking Success of Paddlefish in Lake Francis Case, South Dakota: Population Characteristics and Sport Fishery Potential

Abstract Lake Francis Case, South Dakota, a Missouri River reservoir, supported a paddlefish Polyodon spathula sport fishery shortly after impoundment, but this fishery closed in 1986 owing to a lack of natural recruitment. Lake Francis Case has been stocked intermittently since 1974 and annually since 1990 to maintain the population and potentially sustain a sport harvest. To evaluate the success of these stockings, we assessed the current status of the Lake Francis Case paddlefish population (i.e., population characteristics and dynamics) and evaluated the potential effects of exploitation on this population. Advanced fingerling stockings have been effective, as 56% of sampled fish were of hatchery origin (indicated by coded wire tags), and may sustain a harvestable population. Year-class strength was negatively correlated to water temperature inputs from Big Bend Dam and positively correlated to White River discharge. Downstream emigration is probably responsible for most of the variability in year-cla...

Effect of a Simulated Cold-Front on Hatching Success of Yellow Perch Eggs

ABSTRACT Gradually warming water temperature during yellow perch (Perca flavescens) egg and larval stages has been associated with stronger year classes, whereas an abrupt drop in temperature associated with a cold-front during this period can result in weaker or missing year classes, presumably because of egg or larvae mortality. We subjected yellow perch eggs to sudden declines in temperature and then monitored hatching success of those eggs relative to eggs held at a constant temperature. An experiment in 2007 decreased water temperature by 6°C in 24 h; however, no significant difference in mean hatching success was observed between treatment (48%, SE=5.8) and control tanks (55%, SE=6.0). Another experiment in 2008 decreased water temperature by 8°C in 45 min. Again no significant difference in hatching success was observed between treatment (37%, SE=5.6) and control tanks (38%, SE=5.0). Abrupt temperature drops did not reduce hatching success of yellow perch in laboratory experiments and thus do not appear to be a mechanism affecting perch recruitment at the egg stage tested in our two trials.