SREL Reprint #2047




Is Macroinvertebrate Drift a Density-Dependent Mechanism of the
Benthos in the Lower Mississippi River?

Peter Koetsier
Savannah River Ecology Laboratory
Division of Wetlands Ecology
Drawer E
Aiken, SC 29802


C. Frederick Bryan
Louisiana Cooperative Fisheries Research Unit
U.S. National Biological Service
124 Forestry Bldg.
Louisiana State University
Baton Rouge, LA 70803


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 chirononiids. 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.


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