Skip to main content
U.S. flag

An official website of the United States government

Invertebrate and fish assemblage relations to dissolved Oxygen minima in lowland streams of southwestern Louisiana

November 12, 2012

Dissolved oxygen (DO) concentrations in lowland streams are naturally lower than those in upland streams; however, in some regions where monitoring data are lacking, DO criteria originally established for upland streams have been applied to lowland streams. This study investigated the DO concentrations at which fish and invertebrate assemblages at 35 sites located on lowland streams in southwestern Louisiana began to demonstrate biological thresholds.Average threshold values for taxa richness, diversity and abundance metrics were 2.6 and 2.3 mg/L for the invertebrate and fish assemblages, respectively. These thresholds are approximately twice the DO concentration that some native fish species are capable of tolerating and are comparable with DO criteria that have been recently applied to some coastal streams in Louisiana and Texas. DO minima >2.5 mg/L were favoured for all but extremely tolerant taxa. Extremely tolerant taxa had respiratory adaptations that gave them a competitive advantage, and their success when DO minima were <2 mg/L could be related more to reductions in competition or predation than to DO concentration directly.DO generally had an inverse relation to the amount of agriculture in the buffer area; however, DO concentrations at sites with both low and high amounts of agriculture (including three least-disturbed sites) declined to <2.5 mg/L. Thus, although DO fell below a concentration that was identified as an approximate biological threshold, sources of this condition were sometimes natural (allochthonous material) and had little relation to anthropogenic activity.

Citation Information

Publication Year 2012
Title Invertebrate and fish assemblage relations to dissolved Oxygen minima in lowland streams of southwestern Louisiana
DOI 10.1002/rra.2623
Authors B.G. Justus, Scott V. Mize, Daniel Kroes, James E. Wallace
Publication Type Article
Publication Subtype Journal Article
Series Title River Research and Applications
Series Number
Index ID 70155289
Record Source USGS Publications Warehouse
USGS Organization Arkansas Water Science Center