Some lakes are shallow, warm and have numerous aquatic plants. Species such as bass, perch and pike like these warm-water lakes. Other lakes are deep, with large volumes of cold water. These lakes support trout and other salmonid species. Not every lake is suitable for every kind of fish. Temperature and oxygen levels are the two major factors that control whether or not certain fish species are present. Other factors such as available habitat, competing species and stocking practices also influence fish species.
Declining water quality may result in the loss of a cold-water fishery. Increased nutrients, for example, can ultimately lead to the loss of oxygen in the deeper regions of the lake. Once cold-water fish habitat is lost, it usually cannot be restored – and rarely can it be restored to support trout.
Although we associate fishing with lakes and streams, some lakes and streams have no fish. These areas provide habitat for frogs and salamanders, critical species for many ecosystems. It is very important to protect remaining amphibian habitat.
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