My research program encompasses both fundamental and applied aspects of fish ecology, integrating perspectives from behavioral ecology and evolution with fisheries management and conservation biology. The general approach involves tests of questions or models of broad theoretical and/or practical interest. This is done using a range of approaches from controlled laboratory experiments to large-scale field experiments, as well as more theoretical approaches including phylogenetically-based comparative analyses at the species and higher taxonomic levels. The work has been applied to evaluate and improve fishery management in marine and freshwater ecosystems, with a particular focus on salmonid fishes. There are two overriding themes of the program: (1) the role of behavioral and life history diversity in the dynamics of fish populations, particularly as it applies to their sustainability; and (2) ecological consequences of the artificial culture, and intentional and unintentional release of fish.

The linking of population consequences of organism level processes is a research area of theoretical and applied importance, which can greatly improve our ability to predict future behavior of both individuals and populations in changing environments and during exploitation. This first research theme encompasses studies in both marine and freshwater environments addressing issues such as the effects of temporal and spatial scales in fisheries management (e.g., Armstrong et al. 1998; Fleming 1998) and examinations of the effects of population size and female reproductive allocation on population stability in salmon (submitted to the Journal of Animal Ecology). The theme also explores the reproductive ecology of fishes, which has been a long-standing component of my research program (Fleming 1994, 1996, 1998; Fleming et al. 1997; Fleming and Gross 1989, 1990, 1994) and continues to be (Fleming & Reynolds, in press; Einum & Fleming 2002; Einum, Hendry & Fleming 2002). This work identifies the key role that the breeding system plays in the ability of salmonid populations, for instance, to respond to human-induced disturbance at both temporal and spatial scales. It has also examined how various natural and sexual selective forces, including fishing, have likely affected the evolution of body size, secondary sexual characters, sexual dimorphism and the expression of alternative male tactics (Fleming & Gross 1994; Fleming et al. 1997; Fleming 1998; Fleming & Reynolds, in press). I also continue to explore the evolution of, and critical role that maternal effects (e.g., spawning time and egg size) play in offspring survival and performance (Fleming & Gross 1990; Jonsson et al. 1996; Einum & Fleming 1999, 2000a, b, 2002; Einum, Hendry & Fleming 2002). This work, together with that on breeding performance, indicates that current management practices using population numbers and/or biomass to estimate recruitment potential in fish populations may be misleading when they ignore the contribution of female phenotype to reproductive performance. I am also currently involved in collaborative work with the Italian marine institute, COISPA, to examine the use of marine reserves and translocations of fish to restore the endangered grouper, Epinephelus marginatus, in Sicily (Lembo et al. 1998, 1999, 2002). A final component of the theme, recently initiated, examines habitat associations and life history of Pacific coast groundfish (e.g., dogfish shark [Squalus acanthias], rockfish [Sebastes spp.] and lingcod [Ophidon elongates]), and involves graduate students and collaborators at NOAA Fisheries.

The second theme of my research program addresses the implications, and management of the intentional and unintentional release of cultured fish. It involves empirical studies of behaviour, morphology, genetic divergence, reproductive capabilities, gene flow and competitive interactions associated with the artificial culture and release of fish, particularly salmonids (Fleming & Gross 1989, 1992, 1993, 1994; Jonsson & Fleming 1993; Fleming et al. 1994, 1996, 1997, 2002; Einum & Fleming 1997; Fleming & Einum 1997; Singer et al. 2002; Hindar & Fleming, in press). This work has identified the relative roles of environment and genetics (i.e. non-indigenous origins and domestication) in the divergence of cultured fish from their wild state (Fleming and Gross 1989; Fleming et al. 1994, 1997, 2002; Einum & Fleming 1997; Fleming & Einum 1997). Moreover, it showed that this divergence impairs the performance of cultured fish in nature, particularly during reproduction (Fleming and Gross 1992, 1993; Fleming et al. 1996, 1997) and, ultimately, in terms of lifetime reproductive success (Fleming et al. 2001; Fleming and Petersson 2001; Hindar and Fleming, in press). More recently, this work has been extended to examine the potential for genetic introgression beyond the first generation of introduction/invasion and the possibility of outbreeding depression (Garant et al., submitted). The results of this work indicate that inappropriate management of cultured fish has the potential to impact the productivity and genetic integrity of wild populations, and thus their long-term viability. In a related vein, I am collaborating on a project to examine the design of long-term captive breeding programs. This involves multi-generation experiments using Trinidadian guppies, Poecilia reticulata, as a model species to explore various design options for the successful rearing and re-introduction of fishes.

My research thus combines applied and fundamental approaches of ecology with fisheries, aquaculture and conservation. It involves collaborations with scientists from a broad range of disciplines, academic institutions and government agencies, both at national and international levels, and co-operative interactions with the public.