Acoustic measures of the abundance and size of pelagic planktivores in Lake Michigan

Canadian Journal of Fisheries and Aquatic Sciences
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Abstract

Based on acoustic data taken at night and vertically stratified by bottom depth (3–110 m only), the total number (± 95% Cl) of pelagic fishes in Lake Michigan was 43.4 ± 10.1 x 109 or 226.0 ± 55.2 kt in spring (mean density 0.7–3.8 fish·m-2 or 1.6–12.8 ga·m-2) and 115.8 ± 18.3 x 109 or 313.2 ± 74.3 kt in late summer, 1987 (mean density 1.1–7.0 fish·m-2 or 3.0–13.2 g·m-2); approximately 30% of this increase in numbers (35% of biomass) occurred within Green Bay. Abundance estimates from horizontally stratified (by water column depth) data were within 9-11% of vertically stratified estimates during spring but over 20% higher during summer. By extrapolation to all water depths, we estimated total pelagic biomass as 274.6 kt for spring and 410.8 kt for summer. During both seasons, smaller fishes were nearer to the surface and nearer shore than larger individuals, and acoustic measures of size approximated the sizes of fishes caught in trawls. Bioenergetic model simulations suggest that 60% of the available production of alewife (Alosa pseudoharengus) was either consumed by stocked salmonines (52.9%) or commercially harvested (7.1%) in 1987. Underwater acoustics proved a valuable tool for lakewide assessments of fish abundances in the Great Lakes.

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Acoustic measures of the abundance and size of pelagic planktivores in Lake Michigan
Series title Canadian Journal of Fisheries and Aquatic Sciences
DOI 10.1139/f91-106
Volume 48
Issue 5
Year Published 1991
Language English
Publisher NRC Research Press
Publisher location Ottawa, Ontario
Contributing office(s) Great Lakes Science Center
Description 15 p.
Larger Work Type Article
Larger Work Subtype Journal Article
Larger Work Title Canadian Journal of Fisheries and Aquatic Sciences
First page 894
Last page 908
Country United States
State Michigan
Other Geospatial Lake Michigan