Analysis and Interpretation of Freshwater Fisheries Data

2: Fisheries Management Study Design Considerations

Richard L. Noble, Douglas J. Austen, and Mark A. Pegg


Fisheries management is broadly defined as the art and science of providing sustained aquatic resource productivity. Specifically, management is usually the process of maintaining fish populations at some target level, commensurate with the capacity of the environment and in accordance with established management objectives that are set with consideration of user or constituent needs (e.g., Bennett 1971). In short, fisheries management is the integration of the fish, habitat, and user dimensions of the resource to yield a given product or set of products. Usually this is done through manipulation of one or more of these dimensions (the “action”; Krueger and Decker 1999); however, a stable, viable resource may need only protection or, in some cases, no manipulation or management of any kind. Hence, the adage “no management is management” pertains as well. In either case, resource studies by fisheries scientists, both researchers and managers, are an integral part of understanding the aquatic resources and how best to manage them.

It is a common misperception that fisheries scientists must be data rich to conduct effective management. Perhaps that is where the art of management enters and the conventional-wisdom approach (Johnson 1999) is employed. For example, consider that any of us fortunate enough to have a home with a lawn is a resource manager. Much like a fishery manager who assumes responsibility for a resource in his or her jurisdiction, we buy our first, probably previously owned, home, and we inherit a more or less managed lawn resource. We want something quantitatively or qualitatively different, so we visualize what we want and begin to think of management strategies to meet our goals. Do we gather data on the exact size of the lawn, its precise mix of species, the amount of unvegetated space between clumps, or the rate of growth before and following each cutting? Do we develop computer models that integrate functional relations among the grass, the environment (e.g., soil, water, and fertility), and the lawnmower? Probably we do not. Instead, we begin a management program, and the lawn likely improves, sometimes even to the point of our satisfaction. Our goal has been achieved. At most we may have had a soil test, checked with retail or extension consultants for recommendations on grass varieties, fertilized according to general prescriptions, applied pesticides remedially, watered during droughts, and periodically adjusted the height at which we mowed. A level of success in management was achieved without an assessment-rich or data-rich approach.