Is Macroinvertebrate Drift a
Density-Dependent Mechanism of the
Benthos in the Lower Mississippi River?
Savannah River Ecology Laboratory
Division of Wetlands Ecology
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
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.
To request a reprint