U.S. Dept. of Commerce / NOAA / OAR / PMEL / Publications
A major area of research in fisheries oceanography examines relationships between recruitment dynamics of fish populations and the marine environment. A primary goal is to understand the natural causes of variability in year-class strength of commercially valuable species and apply this knowledge to management [Perry, 1994]. The paradigm that the majority of mortality occurs during transport of early life history stages from spawning to nursery grounds [Rothschild, 1986; Houde, 1987] provides an initial temporal focus for most research. The spatial domain includes the region occupied by early life history stages. Since global climate variability impacts regional ecosystem dynamics, however, the spatial domain often must be expanded. The relative importance and manifestation of biological factors (starvation and predation) that limit survival varies each year. Marked interannual and longer period variations in temperature (an influence on metabolic rates and behavior), transport of planktonic stages, and turbulence can exert an influence on both survival of early life history stages, and distribution of juveniles and adults. To understand how these environmental factors influence reproductive success of fish stocks also requires knowledge of the impact of these factors on predators and prey throughout the food web.
Our research, Fisheries-Oceanography Coordinated Investigations (FOCI, a NOAA
program), examines recruitment dynamics of walleye pollock (Theragra chalcogramma)
in Alaskan ecosystems [Reed
et al., 1988; Schumacher
and Kendall, 1991; Reed
et al., 1994]. Fisheries oceanography is a very broad field of research
with many programs and various approaches; FOCI represents a subset of this
research. FOCI began in 1984 in Shelikof Strait, Alaska; in summer 1991 another
element (a component of NOAA's Coastal Ocean Program) began in the Bering Sea.
Pollock constitute the world's largest single species fishery with annual catches
from Alaskan waters exceeding 1.2 million metric tonnes [Westpested,
1993]. In both regions, large variations in recruitment
The inherent complexity of the ecosystem requires research specialization, which then must be integrated to provide a useful product. A better understanding of the population dynamics process requires more interdisciplinary research among fisheries scientists and oceanographers [Beamish et al., 1989]. Unfortunately, such varied backgrounds traditionally result in disparate rather than integrated research [Wooster, 1986]. The tendency to do research without being responsible for implementation of results also detracts from achieving holistic goals. It has long been known that humans impact their environment. "Man did not weave the web of life; he is merely a strand of it. Whatever he does to the web, he does to himself" (Chief Seattle, 1854). Integrating research conducted by people from disparate academic backgrounds and maintaining a goal of responsible implementation of results can ensure that fishing mortality does not detrimentally interact with natural fluctuations in recruitment. In this way we acknowledge the gifts nature provides and leave a legacy for future generations. This is not only our moral responsibility, it is mandated by Federal law (Magnuson Fisheries Management and Conservation Act, 1976).
In this overview, we present some of the major developments and results from FOCI. First, we present background information for both FOCI programs (Shelikof Strait and Bering Sea), including research strategy and regional circulation features. We then present results that couple the biology and physics and are important features in both programs, as are the methods and techniques that follow. Finally, we present the application of research results from Shelikof Strait FOCI to management. The goal of FOCI, to understand natural fluctuations in year-class strength of pollock and to provide information to reduce uncertainty in status-of-pollock-stock models, is applied science. The initial examination of the physical and biological environment and the time/space distribution of various life history stages of pollock is viewed as fundamental science. Development and implementation of models to integrate biophysical observations, and technologies to measure conditions, as well as developing methods to apply new findings to management occur as FOCI matures.
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