Fish and Fisheries Ecology.

My paper on fish and fisheries ecology is offered to demonstrate a rich blending of applied and fundamental ecology, achieved by the intersections among fishery science, ichthyology, and ecology. The example, while specific, parallels practices and opportunities available in other areas of applied ecology. The emergence of fish and fisheries ecology as a discipline is evidence by such recent textbooks as Fisheries ecology by Pitcher and Hart (1982) and Ecology of teleost fishes by Wootton (1990). The ecology relevant to fish and fisheries includes not only marine and freshwater ecology, oceanography, and limnology, but also terrestrial study. Early work in fish and fisheries ecology came from Stephen A. Forbes > 100 yr ago in his books On some interactions of organisms (Forbes 1880) and The lake as a microcosm (Forbes 1887). These constitute one of the earliest conceptualizations of an ecosystem. By 1932 E. S. Russell concluded that fishery research was a study in marine ecology. I give examples of applications from six different categories of ecology. (1) Physiological ecology: The F. E. J. Fry school of fish physiology developed the concepts of temperature as a lethal, controlling and directive factor. More than 40 yr later, this knowledge is being combined with G. E. Hutchinson's concept of an n-dimensional niche to analyze potential influences of global climate warming on fishes. (2) Behavioral ecology: A. D. Hasler and students formulated and tested the hypothesis of olfactory imprinting as the mechanism by which Pacific salmon "home" to their natal spawning streams. Applications to reestablish salmon runs are as important to Hasler as the original scientific discovery; this is evident in his proposed "Salmon for Peace" for the river bounding USSR and China. (3) Population ecology: The realization that reproductive success of fishes depends more on larval mortality than on egg production emerged from the ideas of J. Hjort (1914). To this day inconsistencies between recruitment and reproductive stock size impart uncertainty into fishery management, while the search for explanatory mechanisms attracts the curious mind. (4) Community ecology: Species interactions are the grist of community ecology; predation and fishing are a natural for comparative study and application. Also, consumption by fish can control the dynamics of planktonic and benthic animal/plant communities; thus, apparent water quality of lakes depends on the consumer community as well as on nutrient inputs. (5) Ecosystem ecology: D. S. Rawson grouped external, abiotic influences on lakes into climatic, edaphic, and morphometric factors. The morphoedaphic index (Ryder 1965) predicts fish yields from this base, providing fish managers with a useful approximation and ecologists with a conceptual base for synthesis of production processes. (6) Landscape ecology: Regional ecology often incorporates land-water boundaries into the way ecological systems work. Application of island biogeography to lakes, as islands, has allowed predictions of fish assemblages for use by managers. Also, the extent and connectedness of lake and ocean "landscapes" offer insight into contrasts between marine and freshwater fishery research and management. In conclusion, the ecotone between academic and applied ecology seems an ideal place from which to advance both applied ecology and ecology in general.