SREL Reprint #2047

Is macroinvertebrate drift a density-dependent mechanism of the benthos in the lower Mississippi River?

Peter Koetsier1 and C. Frederick Bryan2

1Savannah River Ecology Laboratory, Division of Wetlands Ecology, Drawer E, Aiken, SC 29802
2Louisiana Cooperative Fisheries Research Unit, U.S. National Biological Service, 124 Forestry Bldg.,
Louisiana State University, Baton Rouge, LA 70803

Abstract: In the lower Mississippi River, we sampled drifting and benthic macroinvertebrates each month from November, 1984 to June, 1985. Drift was dominated by hydroids, Chaoborous punctipennis (Diptera), Taphromysis louisianae (Mysidacea), and decapod shrimp. The chief components of the benthic community were tubificid oligochaetes and chironomids. The species composition of the drift was significantly different from that of the benthos, for all but one month. We concluded that drift is not a density-dependent function of the bottom fauna in the lower Mississippi River. This information adds strength to the argument that, in very large rivers, drift may be a separate community from the benthos.

SREL Reprint #2047

Koetsier, P. and C.F. Bryan. 1996. Is macroinvertebrate drift a density-dependent mechanism of the benthos in the lower Mississippi River? Journal of Freshwater Ecology 11:1-10.

This information was provided by the University of Georgia's Savannah River Ecology Laboratory (srel.uga.edu).