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Variations in Abundance of Young-of-the-Year Channel Catfish in a Navigation Pool of the Upper Mississippi River

1988; Wiley; Volume: 117; Issue: 2 Linguagem: Inglês

10.1577/1548-8659(1988)117 2.3.co;2

1548-8659

Leslie E. Holland‐Bartels, Michael Duval,

Fish Biology and Ecology Studies

Spatial and temporal variations in the abundance of young-of-the-year channel catfish Ictalurus punctatus were determined over 3 years based on 154 trawls taken from Navigation Pool 7 of the upper Mississippi River. No significant spatial patterns in abundance or length offish in the catch were found in seven poolwide surveys of the main channel. However, high variation among replicates existed. Temporal patterns in abundance and length-frequency distributions varied among the study years. Seasonal catch curves were similar in 1984 and 1986, although offset due to earlier spawning in 1986. Spawning appeared to have been protracted in both years, based on analyses of back-calculated dates of spawn and length-frequency patterns of young. Sixty to seventy percent more young were produced in 1985, when spawning occurred over a shorter period of time and a more uniformly sized year class was produced. These annual variations in year-class characteristics are hypothesized to have resulted in part from different river discharge patterns in the 3 years of the survey, with high discharge in 1984 and 1986 negatively affecting production of young.