Bottom Trawl Explorations in Southern Lake Michigan, 1962-65

Date

1969-02

Journal Title

Journal ISSN

Volume Title

Publisher

United States Department of the Interior, Fish and Wildlife Service, Bureau of Commercial Fishes

Abstract

For 4 years the Bureau of Commercial Fisheries Exploratory Fishing and Gear Research Base at Ann Arbor, Mich., surveyed the abundance, seasonal availability, and depth distribution of various fish stocks. The alewife (Alosa pseudoharengus) and chubs (Leucichthys spp.) were taken readily with the bottom trawl. Alewives composed 51.4 percent and chubs 44.0 percent of the trawl catch. Two other commercial species, yellow perch (Perca flavescens) and smelt (Osmerus mordax), were taken occasionally in commercial amounts. The alewife stocks have increased tremendously in recent years. The poundage of alewives in the trawl catch increased each year from 17 percent in 1962 to 74 percent in 1965. Alewives exhibited pronounced seasonal movements and generally were available to bottom trawls only at specific depths. The trawls caught alewives at depths of less than 5 fathoms to over 50 fathoms. Alewives appeared to be distributed universally in the study area during most of the year but were found only in some sections in winter. Alewives were more difficult to catch between July and the end of December than during January through June. Chubs were abundant all year throughout southern Lake Michigan. Chubs were caught over a wide depth range throughout the year, although bottom trawling indicated some horizontal dispersal shoreward in summer and back to deeper water in fall.

Description

39 pages; available for download at the link below.

Keywords

trawls and trawling, chub (fish), alewife (fish), stock assessment, species composition

Citation