Project located within the Rock Island District, Mississippi River Pool 13
Mussel sampling in large turbid rivers
Large riverine biological survey and assessment
Surface supplied air diving
U.S. Fish and Wildlife Service issued a jeopardy opinion to the Corps in April 2000 for the continued operation of the 9ft navigation channel. The opinion stated that commercial barge transportation would “facilitate a continued and maintained source of zebra mussels in the UMRS and thus, appreciably reduce the likelihood of survival and recovery” of the endangered Lampsilis higginsii. An interagency Mussel Coordination Team (MCT) was established to address reasonable and prudent alternatives (RPAs) and reasonable and prudent measures (RPMs) concerning jeopardy and incidental take of L. higginsii.
The Team believed that recovery of the species could not be accomplished without maintaining the Essential Habitat Area (EHA) populations. A monitoring program was developed to evaluate long-term trends of L. higginsii and other native unionid populations within the EHAs. Ecological Specialists, Inc. used a combination of quantitative, semi-quantitative, and qualitative survey methods to evaluate the unionid community at the Bellevue EHA. Quantitative samples were collected to determine unionid density and accurately assess community metrics. Qualitative samples were collected in 6 of the highest density areas within the EHA to increase the likelihood of collecting rare species; additional qualitative samples were conducted outside the EHA boundary to verify the accuracy of the existing boundary. Semi-quantitative samples were collected to aid in defining the upstream and downstream limits of the mussel bed and to identify areas of greatest unionid abundance outside the EHA.
Community metrics were compared to past monitoring events to evaluate trends in mussel community health over time. In addition to the Bellevue EHA, ESI has conducted similar monitoring at several other L. higginsii EHAs and relocation areas throughout the Upper Mississippi River in recent years.