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Status of the amphipod Diporeia Spp. in Lake Superior, 2011
Citation:
Scharold, J., J. Kelly, AND T. Corry. Status of the amphipod Diporeia Spp. in Lake Superior, 2011. Presented at Joint Aquatic Sciences Meeting, Portland, OR, May 18 - 23, 2014.
Impact/Purpose:
not applicable
Description:
Amphipods of the genus Diporeia have historically been the dominant benthic macroinvertebrates in deeper waters of the Laurentian Great Lakes. Although Diporeia populations in the lower Great Lakes have experienced severe declines in recent years, densities have remained relatively stable in Lake Superior. We used a probability survey design to assess population density of Diporeia in Lake Superior. During September 2011, Diporeia were sampled at 53 sites using a Ponar grab. 24 sites were in the nearshore (0-100 m depth) stratum and 29 in the offshore (>100 m) stratum. The lake-wide mean density of Diporeia was 855 + 146 (SE) m-2. In nearshore and offshore regions, mean densities were 1482 + 184 m-2 and 688 + 180 m-2, respectively. These values are greater than those from a similar survey conducted in 2006 (lake-wide mean 446 + 63m-2), and are much higher than those reported from the only previous comprehensive lake-wide survey of Diporeia, conducted in 1973. Greater understanding of the spatial and temporal variability of Diporeia populations will assist further refinement of monitoring designs.