Fish Communities

Although the following units discuss various sport fish in singular detail, it is important to realize that fish do not exist in isolation. How a particular fish reacts to the other members of its aquatic community has a profound effect on the individual fish and your angling approach to it.

The aquatic community is a complex interrelationship of biological organisms, including fish constantly reacting to each other and changes in the aquatic environment. A healthy environment is necessary to produce healthy populations of fish.

Managers of fish communities are constantly concerned with the balance within these communities. However, fragmentation of jurisdiction has long been the bane of aquatic resource managers. Often, separate agencies have responsibility for water quality, water levels, and the fish populations of one lake or river system. To complicate matters, a healthy fishery is often only one of many management objectives. Navi-gation, power production, tourism, industry, urbanization, and agri-culture must also be maintained. The complications multiply in cases involving several levels of govern-ment. In international water bodies like the Great Lakes it is conceivable to have ten or 15 agencies represent-ing various levels of government all taking actions which directly affect a single fish community.

Sport or commercial fishing centred around a specific species or group of species can take its toll on a community. Ideally, fishing pressure should be spread across the widest possible range of species. Fishing can be used as a management tool in many cases. By redirecting fishing pressure, managers can promote the recovery of waning populations and help prevent stunting and disease due to overcrowding in others.

The introduction of exotic species can also throw a fish community into imbalance. The accidental introduction of new species by way of fishermen's bait buckets has had serious effects on many fisheries. Where exotic species are introduced on purpose, it must be a carefully con-sidered and monitored decision undertaken by fisheries professionals.

Anglers tend to reach towards stocking fish as the easy answer to every fish population problem. However, stocking is not only an expensive and short-term solution, it is often ineffective. Habitat rehabilitation, by improving spawning beds for example, and water-quality improve-ment, by such efforts as preventing agricultural run-offs, often provide more effective long-term benefits.

To a great extent the natural limits of water temperature control fish species within a community. We can use water temperature as a means of classification, although this system is somewhat artificial. The cold-water community is the usual domain of the salmonids (salmon, trout, and chars). Whitefish, smelt, herring, and ling can often be found here as well. Cool-water fish may sometimes appear confused to the angler. Often they are found in the warmer areas of the cold-water environment or the cooler areas of the warm-water environment. The cool-water community includes the Esocidae (pike and muskie), walleye, smallmouth bass, yellow perch, and perhaps white bass, striped bass, or white perch. Fishes which can coexist comfortably in the warm-water environment include panfish, largemouth bass, carp, suckers, and catfish.

However, the combinations of species which make up natural and human-influenced fish communities are endless. It is also common to find substantially different communities in different parts of a single lake envi-ronment. Under specific conditions, these communities may interrelate but this relationship may change on a seasonal basis.

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