Status of macroinvertebrate populations of the UMR


Eckblad, J. W.  1991.  LTRMP Observational Bulletin No. 1. 
Status of macroinvertebrate populations of the Upper Mississippi
River.  Report by Luther College, Decorah, Iowa, for the U.S.
Fish and Wildlife Service, Environmental Management Technical
Center, Onalaska, Wisconsin, April 1991.  EMTC 91-03.  8 pp. 
(NTIS # PB91-197863)


ABSTRACT

In 1989 and early 1990, biologists began reporting apparent
declines in macroinvertebrate densities at specific Upper
Mississippi River System sites.  The Environmental Management
Technical Center hosted a one-day workshop on May 30, 1990, to
promote an exchange of current information about Upper
Mississippi River System macroinvertebrates, and to review and
document any observations that had been made.  Observations of
declines in fingernail clam populations, over varying periods of
time, were reported for navigation Pools 8, 9, and 19 by workshop
participants.  Large numbers of dead fingernail clams, but no
live specimens, were discussed at the workshop included reduction
in suitable habitat; toxic substances in sediments; water level,
temperature and dissolved oxygen regimes; and biotic factors. 
Workshop recommendations included retrospective data analysis and
the monitoring of several invertebrate communities and associated
abiotic factors. 


KEYWORDS

Macroinvertebrates, Upper Mississippi River System, monitoring