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|Title:||Aquatic habitat studies on the Lower Mississippi River, river mile 480 to 530. Report 6, Larval fish studies--pilot report|
|Authors:||Environmental and Water Quality Operational Studies (U.S.)|
Schramm, Harold L.
Pennington, C. H.
Lower Mississippi River
|Publisher:||Environmental Laboratory (U.S.)|
Engineer Research and Development Center (U.S.)
Abstract: Larval fish were collected in the Lower Mississippi River from 8 March to 13 November 1978 to describe variations in diversity and abundance of larval fish among nine types of habitats for the entire spawning season, investigate diel fluctuations in diversity and abundance, and evaluate replicate sampling procedures. The abandoned channel and oxbow lake habitats had similar larval populations; these habitats showed relatively low diversity and high densities of clupeids and centrarchids. Natural banks and revetted banks had high and similar diversities and abundances of larval fish. There were considerable variations in density and diversity among the four revetted bank stations sampled. The dike field habitat was characterized by a high diversity and moderate density of larval fish. All families of larval fish collected during the entire study were represented in the dike field habitat. The diversity and density of larval fish differed greatly among the six dike field stations sampled. Three of the four main channel stations sampled showed low diversity and density of larval fish. The fourth main channel station had high diversity of larval fish and high densities were observed on two sampling dates. Density of larval fish was low but diversity of larval fish was relatively high in the temporary secondary channel habitat. Density and diversity of larval fish were low in the permanent secondary channel and the sandbar habitats. The number of taxa and density of larval fish differed significantly (probability < 0.01) between time periods of the diel cycle. The number of taxa and the density were greatest at dusk. Twelve taxa were collected only in dusk, night, and dawn samples. Aplodinotus grunniens, Carpiodes spp., and clupeids accounted for 95 percent of the larvae collected during the diel sampling effort. A. grunniens and Carpiodes spp. were more abundant in dusk and night samples. Clupeids were more abundant diurnally. A variance component analysis demonstrated that samples taken within a 1- to 2-hr time period of a diel cycle did not constitute significant (probability < 0.01) amounts of the variation in number of taxa or density of larval fish. The same analysis showed that samples collected with paired nets did not constitute a significant (probability < 0.01) portion of the variation in number of taxa, but did constitute a significant portion of the variation in density of larval fish. Implications for future sampling are discussed. This is report 6 of the series "Aquatic Habitat Studies on the Lower Mississippi River, River Mile 480 to 530."
|Rights:||Approved for public release; distribution is unlimited.|
|Appears in Collections:||Miscellaneous Paper|