Document Type

Article

Publication Date

1989

Publication Title

California Fish and Game

Volume

75

Issue

4

First page number:

218

Last page number:

223

Abstract

Echograms have been used extensively to locate and estimate the relative abundance of marine fish stocks (Cushing 1973). In freshwater, echograms have been used to describe vertical (Netsch et al. 1971; Eggers 1978; O'Brien et al. 1984; Matthews et al. 1985), spatial (O'Brien et al. 1984; Wanjala et al. 1986) and temporal (Baker and Paulson 1983) patterns in fish abundance. Although most uses of echograms have been qualitative, Mullan and Applegate (1969) and Matthews et al. (1985) obtained relative estimates of fish abundance by counting targets (fish) on echograms. However, neither Mullan and Applegate (1969) nor Matthews et al. (1985) presented any statistical analysis of estimates obtained from echograms. Our purposes in this paper are to: 1) describe a procedure we have used for the scoring and statistical analysis of echograms as relative estimates of pelagic fish abundance; and 2) describe temporal and spatial variation in pelagic fish abundance in Lake Mead.

Keywords

Aquatic ecology; Echograms; Environmental quality; Freshwater fishes; Lake Mead National Recreation Area (Ariz. and Nev.); Limnology

Disciplines

Aquaculture and Fisheries | Desert Ecology | Environmental Monitoring | Environmental Sciences | Fresh Water Studies | Life Sciences | Natural Resources and Conservation | Natural Resources Management and Policy | Sustainability | Terrestrial and Aquatic Ecology

Language

English