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beat. <br />5.0 BENTHIC MACROINVERTEBRATES <br />• Invertebrate fauna which inhabit the bottom substrate of water courses <br />are the most frequently used indicators of ambient environmental quality. <br />Their relatively large size facilitates identification and their sessile <br />nature aids in collection. Many benthic macroinvertebrates require specific <br />environmental conditions, which, under change or stress, results in a change <br />in community composition. Thus, knowledge of the kinds and abundance of <br />benthic organisms helps to determine trends in the condition of water quality. <br />Enough is presently known about the general response of benthic communities <br />to environmental disturbances that some general predictions as to the effects <br />can be made once the existing community has been characterized (Hynes 1910; <br />Cairns and Dickson 1973, 1977; Hart and Fuller 1974). <br />• Coupled with their inherent potential as ecological indicators, benthic <br />invertebrates are a major food item of local fish populations (Beckman 1953, <br />Baxter and Simon 1970). These aquatic insects, molluscs, etc. are critical <br />to the food chain of any freshwater system culminating in fish. The <br />importance of invertebrates is primarily in their ability to convert energy <br />entrapped by primary producers to a form capable of being utilized by fish. <br />The specific objective of this study was to characterize the benthic <br />macroinvertebrate community in the North Fork along the permit area in terms <br />of taxonomic composition and abundance. <br />5.1 Methods <br />Benthic macroinvertebrate samples were collected at each of the four <br />sampling sites (Figure 2.0-1) during the November aquatic survey. A <br />5-1 <br />