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The goal of my research program over the next five years will be to quantify patterns and processes associated with individual life-history variation, population dynamics, and community structure for both game and non-game species. Specific objectives are as follows: <OL> <LI> Individuals: Develop projects targeted at understanding individual life histories in A) unstudied or understudied species, B) economically valuable sport fish species, and C) non-game species whose status is currently or potentially threatened. Specific projects will focus on aspects of ecotoxicology (e.g., mercury dynamics and contamination, EDCs and intersex fish) in a variety of game and non-game populations to determine effects on factors such as growth, reproductive status, and behavior. Assessing human consumption risk associated with fish contamination will also be an important component of this research. Additional studies will focus on the ecology (e.g., movement patterns, life history strategies, etc.) of species of local and regional interest in lake, river, and estuarine systems.<LI>Populations: Projects will be developed to examine population structure and dynamics for both game and non-game species. Several specific areas of focus will include 1) examining the impacts of invasive species on lake and reservoir systems, including determining how invasive species influence native populations, 2) understanding the influence of harvest practices on important sport species, and 3) quantifying mechanisms associated with stunting (a phenomenon in which individuals of a certain population remain small compared to conspecifics in other populations).<LI>Communities: Projects will be developed that examine community structure and food web dynamics, particularly in lake and reservoir systems. Specific studies will assess trophic dynamics of reservoir food webs, quantify benthic-pelagic coupling in reservoir systems, evaluate the impacts of invasive fish species on community structure, and model management strategies for important sport species.
Non-Technical Summary: Fish play a central role in aquatic ecosystems through important individual, population-, and community-level interactions (e.g., Thorp and Bergey 1981; Werner and Hall 1988; Aday et al. 2005), yet a variety of factors at each scale remain poorly understood. At the individual level, for example, it is unclear for many species how genetic and environmental factors interact to influence life-history strategies. Inter-population variation in demographics such as size- and age-structure are common (e.g., Danylchuk and Fox 1994; Aday 2008), yet mechanisms associated with this variation are often unclear. Further, the ways that individual behaviors influence population dynamics and the consequences of population-level interactions to community and ecosystem structure are also poorly understood for many species and systems. From a practical standpoint, sportfish management initiatives often focus on individual species, ignoring underlying interactions that can have significant influence on the biology and ecology of the target species and system. Fish also provide a major source of protein for much of the world's population, yet recent investigations have indicated that harvest practices (both commercial and recreational) continue to imperil a number of important species (e.g., Myers and Worm 2003; Coleman et al. 2004); influences on many other species remain unexamined. In addition, contamination of aquatic systems has led to considerable concern about fish consumption. In particular, endocrine disrupting compounds (EDCs) and their effects on fish, wildlife and people have been recently studied. These natural and synthetic chemicals that interfere with hormone-controlled physiological processes include pesticides, pharmaceuticals, insecticides, and certain heavy metals (Helfman et al. 2009). Ongoing research suggests that these compounds can have significant influence on the health of fish, wildlife, and humans (e.g., Wiener and Spry 1996; Drevnick et al. 2006). As such, my research program over the next five years will focus not only on the effects of angling practices on commonly caught and consumed fish species, but also on assessing contaminant dynamics in aquatic systems, identifying mechanisms associated with their chemical transformation, transport, and bioaccumulation, and quantifying impacts on individuals, populations, and communities. In sum, there are both theoretical and practical reasons for studying individual life histories, population dynamics, and community structure for both game and non-game fish species, and research implications extend from advancing scientific theory to enhancing public welfare. In particular, expected outcomes include a change in knowledge (new scientific publications associated with this research project; potential changes in policy as a result of the contaminant research), a change in action (including changes in fishery management practices and a change in fish consumption patterns), and a change in condition (safer food supply, cleaner and healthier environment). <P> Approach: For each of the stated objectives, research will be conducted at a variety of spatial and temporal scales. Mesocosm experiments will be conducted in tanks at a facility currently in the planning stage and research funds will be directed toward this end. Field investigations will be used to determine the influence of biotic and abiotic factors at each ecological scale. Equipment necessary for sampling and processing of samples will be purchased with research funds. More specifics are provided for each objective: Objective 1: These projects are either currently underway or will begin within a year. An ongoing project assessing mercury dynamics in aquatic systems is underway and will continue for at least another year. In particular, an assessment of mercury contamination of commonly caught and consumed marine species will begin this year and will continue for at least a year. Additional work on the relationship between mercury contamination and fish body size, and on the ways in which hurricanes influence mercury dynamics, is underway and will continue for at least a year. A project focusing on intersex fish (i.e., male fish that have female gametes and vice versa) will begin within a year and will continue for several years thereafter. Projects associated with other game and non-game species are currently being developed and will continue throughout the five-year period. Small, laboratory-scale experiments will be performed locally (i.e., at NCSU-associated facilities) and larger, field-scale experiments will occur throughout the state. Objective 2: These projects are currently underway or will begin within the five-year period. Two projects associated with invasive species are currently underway and will continue for the next two years. Specifically, the effects of invasive white perch in NC reservoirs are currently being assessed. Data associated with perch life histories, trophic position, and influence on native species will be collected and analyzed over the next two years. Research on factors associated with stunting is ongoing and will continue for the duration of this five-year segment. A project focused on movement patterns and population dynamics of white bass will be initiated within a year and will continue for several years thereafter. Additional projects will be sought for research throughout North Carolina. Whenever possible, harvest issues will be included in the development of specific projects, with the goal of understanding the influence of harvest practices on fish populations. Objective 3: Community-level projects are underway or will begin within a year. A current project associated trophic dynamics and food web interactions in reservoirs is underway and will continue for another two years. Recently developed techniques such as stable isotope analysis will be used to map species to specific trophic positions within reservoirs, and that information will be used to construct models of food web interactions. Once constructed, those models can be used to assess the impacts of invasive fish species on community structure, and to develop management strategies for native sport species.