Fish and Invertebrate Assemblage Relations to Dissolved Oxygen at 35 Sites in Southern Louisiana

Author(s): Justus, B. ;  Wallace, J.

From 2005 to 2007, the U.S. Geological Survey sampled fish and invertebrate assemblages and monitored dissolved oxygen during critical summer conditions at 35 stream sites in southern Louisiana. The purpose of the study was to assess relations between fish and invertebrate assemblages and dissolved oxygen, and to provide information that could be used to validate or refine existing aquatic life use categories and dissolved-oxygen criteria (5 milligrams per liter) for streams in southern Louisiana. Sites with a range of ecological conditions were selected for sampling by the U.S. Environmental Protection Agency Region VI, and nine sites were considered to be least impaired. Dissolved-oxygen concentrations were standardized to 0800, a time when concentrations were near the daily minimum, and were compared to approximately 370 biological metrics. Piecewise regression was used to evaluate biological metrics for break points to indicate a minimum (biological) threshold concentration for dissolved oxygen. Preliminary data indicate a biological threshold exists between 2 and 3 milligrams per liter of dissolved oxygen. This finding indicates that fish and invertebrate assemblages in low-gradient streams have adaptations that enable them to withstand low dissolved-oxygen concentrations.


Technical Presentations

  • Delta Water Quality
  • Delta Water and Agriculture
  • Wetlands
  • Water Quality
  • Sediments
  • Non-Point
  • Management and Sustainability
  • Wood Treatment
  • Modeling
  • Soil and Water Treatment


Responsible Site Design: Implementing Innovative Stormwater Management Strategies

The primary goal of the workshop is to create a dynamic learning experience that examines the role of stormwater management in the built environment. The workshop will focus on integrating ecologically sound water management approaches into site design. After the workshop, attendees will be familiar with the following concepts and technical issues:

  • Knowledge of the stormwater treatment chain
  • Knowledge of the impact of land use codes on stormwater management
  • Application of a design process that mitigates the effects of stormwater on-site
  • Knowledge of the relationship between land use codes and design for innovative stormwater management


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Jessie Schmidt
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Mississippi State, MS 39762