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Kinmundy, IL, United States

Nannini M.A.,University of Illinois at Urbana - Champaign | Parkos III J.,Florida International University | Wahl D.H.,Sam Parr Biological Station
Transactions of the American Fisheries Society | Year: 2012

Behavioral syndromes often have individuals varying along a continuum of personality traits. Some individuals exhibit bold or aggressive behaviors and are willing to explore novel stimuli, whereas others are shy and tend to avoid novel stimuli. Species that undergo an ontogenetic diet shift may experience a particularly important benefit if the shift to more-profitable prey is linked to this willingness to explore novel stimuli. However, actively selecting more-evasive prey can make these predators more vulnerable to predation themselves. We used largemouth bass Micropterus salmoides as a model to examine the role of behavioral syndromes in structuring predator strategies for dealing with these conflicting environmental pressures. Exploration behavior was first determined by testing willingness to explore a novel environment. Behaviors were then measured in two other contexts where exploration and boldness could potentially have fitness consequences: (1) the likelihood of consuming a novel prey item and (2) movement in the presence of a predator. Fish that tended to be exploratory consumed more total prey biomass than did fish that avoided a novel environment; however, the nonexploratory fish were more discriminating and targeted novel fish prey to a greater extent than did bold fish. Activity in the presence of a predator was not related to any other factor measured. Although our results provide no evidence that behavioral syndromes influence the predator avoidance behavior of largemouth bass, these syndromes do appear to play an important role in prey selection. Our study indicates that although behavioral syndromes do not necessarily affect behavior across all environmental contexts, they may influence feeding strategies and thus could potentially affect the timing of dietary shifts. © American Fisheries Society 2012. Source

Binder T.R.,Carleton University | O'Connor C.M.,Carleton University | McConnachie S.H.,Carleton University | Wilson S.M.,Carleton University | And 3 more authors.
Comparative Biochemistry and Physiology -Part A : Molecular and Integrative Physiology | Year: 2015

Over-winter mortality is an important selective force for warm-water fish (e.g., centrarchids) that live in temperate habitats. Inherent challenges faced by fish during winter may be compounded by additional stressors that activate the hypothalamic-pituitary-interrenal axis, either before or during winter, leading to negative sub-lethal impacts on fish health and condition, and possibly reducing chance of survival. We used experimental cortisol manipulation to test the hypothesis that juvenile largemouth bass (. Micropterus salmoides) exposed to semi-chronic elevation in cortisol prior to winter would experience higher levels of over-winter mortality, physiological alterations and impaired immune status relative to control and sham-treated bass. Over-winter survival in experimental ponds was high, averaging 83%, and did not differ among treatment groups. Over the study period, bass exhibited an average increase in mass of 19.4%, as well as a slight increase in Fulton's condition factor, but neither measure differed among groups. Hepatosomatic index in cortisol-treated bass was 23% lower than in control fish, suggesting lower energy status, but white muscle lipid content was similar across all groups. Lastly, there was no difference in spleen somatic index or parasite load among treatment groups, indicating no long-term immune impairment related to our cortisol manipulation. The current study adds to a growing body of literature on glucocorticoid manipulations where field-based findings are not consistent with laboratory-based conceptual understanding of multiple stressors. This suggests that field conditions may provide fish with opportunities to mitigate negative effects of some stressors. © 2015 Elsevier Inc. Source

Nannini M.A.,Sam Parr Biological Station | Wahl D.H.,Sam Parr Biological Station | Philipp D.P.,University of Illinois at Urbana - Champaign | Cooke S.J.,Carleton University
Journal of Fish Biology | Year: 2011

Several traits related to foraging behaviour were assessed in young-of-the-year produced from largemouth bass Micropterus salmoides that had been exposed to four generations of artificial selection for vulnerability to angling. As recreational angling may target foraging ability, this study tested the hypothesis that selection for vulnerability to angling would affect behaviours associated with foraging ecology and prey capture success. Fish selected for low vulnerability to angling captured more prey and attempted more captures than high vulnerability fish. The higher capture attempts, however, ultimately resulted in a lower capture success for low vulnerability fish. Low vulnerability fish also had higher prey rejection rates, marginally shorter reactive distance and were more efficient at converting prey consumed into growth than their high vulnerability counterparts. Selection due to recreational fishing has the potential to affect many aspects of the foraging ecology of the targeted population and highlights the importance of understanding evolutionary effects and how these need to be considered when managing populations. © 2011 The Fisheries Society of the British Isles. Source

O'Connor C.M.,Carleton University | O'Connor C.M.,McMaster University | Nannini M.,Sam Parr Biological Station | Wahl D.H.,Kaskaskia Biological Station | And 3 more authors.
Journal of Experimental Zoology Part A: Ecological Genetics and Physiology | Year: 2013

Experimental implants were used to investigate the effect of elevated cortisol (the primary stress hormone in teleost fish) on energetic and physiological condition prior to reproduction in male and female largemouth bass (Micropterus salmoides). Fish were wild-caught from lakes in Illinois, and held in experimental ponds for the duration of the study. Between 9 and 13 days after cortisol treatment, and immediately prior to the start of the reproductive period, treated and control animals were sampled. Females exhibited lower muscle lipid content, lower liver glycogen content, and higher hepatosomatic indices than males, regardless of treatment. Also, cortisol-treated females had higher hepatosomatic indices and lower final mass than control females, whereas males showed no differences between treatment groups. Finally, cortisol-treated females had higher gonadal cortisol concentrations than control females. In general, we found evidence of reduced energetic stores in female fish relative to male fish, likely due to timing differences in the allocation of resources during reproduction between males and females. Perhaps driven by the difference in energetic reserves, our data further suggest that females are more sensitive than males to elevated cortisol during the period immediately prior to reproduction. © 2012 Wiley Periodicals, Inc. Source

Nannini M.A.,Sam Parr Biological Station | Goodrich J.,Illinois Natural History Survey | Dettmers J.M.,Illinois Natural History Survey | Soluk D.A.,Illinois Natural History Survey | And 2 more authors.
Ecology of Freshwater Fish | Year: 2012

The spatial and temporal complexity of large river ecosystems likely promotes biological diversity within riverine larval fish assemblages. However, the focus of most previous riverine studies of larval fish distribution has tended to concentrate mainly on backwater habitats. There has been less focus on the value of the main channel for larval fishes. We sampled two habitats types (three main channel sites and three backwater lakes) along 20 km of the Illinois River ecosystem during 2 years to compare the larval fish distribution along both spatial and environmental gradients between these habitats. Across the 2 years of this study, we found similar trends in the spatial and temporal distribution of larval fish, although there were some differences in densities between years. The relative abundance and size of many of the different fish taxa varied among habitats. Centrarchids, clupeids, poeciliids, cyprinids (excluding common carp) and atherinids were more abundant within backwater lake habitat. In contrast, common carp (Cyprinus carpio), sciaenids, moronids and catostomids were more abundant in main channel habitats. Furthermore, sciaenid and clupeid larvae captured in the backwater lake habitat were larger as the season progressed than those captured in the main channel. Our study suggests that larval fish show habitat specialisation, similar to adults, indicating that both the backwater lakes and the main channel are both important for larval fish and preserving the diversity of the fish assemblages in large floodplain rivers. © 2012 John Wiley & Sons A/S. Source

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