• Benthic Macroinvertebrate Community Changes Following Zebra Mussel Colonization of Southwestern Lake Ontario

      Stewart, Timothy W.; The College at Brockport (1993-08-01)
      Changes in abundance and diversity of benthic macroinvertebrates inhabiting a natural cobble and artificial reef substrate in southwestern Lake Ontario were quantified following invasion of the zebra mussel, Dreissena polymorpha. Post-zebra mussel invasion data (1991-92) were statistically compared with pre-invasion data (1983) from the same sites. By 1991-92 zebra mussels comprised 73% and 90% of cobble and artificial reef macroinvertebrates, respectively, replacing the amphipod Gammarus fasciatus as the numerically dominant taxon at both sites. Overall abundance of non-zebra mussel taxa was significantly greater (p < 0.05) at cobble and artificial reef sites in 1991-92, than in 1983 before zebra mussels were present. Taxa exhibiting significant population increases at the cobble site during the time period separating the two studies were the annelids Manayunkia speciosa, Spirosperma ferox and unidentified tubificids; the gastropods Helisoma anceps,Physa heterostropha, Stagnicola catascopium, Valvata tricarinata, Goniobasis livescens and Amnicola limosa; and the arthropods Gammarus fasciatus and Orconectes propinquis. Significant population increases of Physa heterostropha, Goniobasis livescens, Amnicola limosa, Gammarus fasciatus and the trichopteran Polycentropus were observed at the artificial reef site. Although a few taxa sampled infrequently in 1983 were not collected in 1991-92, no taxa have decreased significantly since 1983. Comparisons of community composition in 1983 and 1991-92 suggest the cobble community has changed more than the artificial reef community. These changes are likely positive, as species richness was greater at cobble and artificial reef sites in 1991-92 relative to 1983, and Simpson's Diversity showed no decline. Though other factors may have contributed to observed native macroinvertebrate community changes, my results support theories that zebra mussels are facilitating energy transfer to the benthos by filter-feeding, and that mussel shoals are providing additional habitat for native invertebrate taxa.
    • Burrowing Saves Lake Erie Clams

      Nichols, S. Jerrine; Wilcox, Douglas A.; The College at Brockport; U.S. Geological Survey (1997-10-01)
      Native clams seem to have been protected from zebra mussel infestation at Metzger Marsh by the interaction between warm temperatures and soft sediments. Warm water encourages burrowing, but soft sediments are required to allow encrusted clams to burrow. In support of this conclusion, we have since found live unionids or fresh shells at three other Lake Erie wetlands.
    • Studies of Adult and Larval Zebra Mussel Populations in Conesus Lake, NY

      Bosch, Isidro; Shuskey, Todd; Collins, Thomas; Smith, Alyssa; SUNY Geneseo (2013-07-01)
      The goal of this study was to assess the status of the zebra mussel population (Family Dreissinidae, species Dreissena polymorpha) in Conesus Lake by sampling benthic adults and planktonic larvae during the summer reproductive season. Another invasive dreissinid bivalve, the quagga mussel, D. bugensis, has firmly established itself in some of the larger Finger Lakes, including Seneca and Canandaigua Lake. Therefore a second goal of this study was to determine if quagga mussels had invaded Conesus Lake. In this report we provide data on population numbers and size distribution of adult zebra mussels and describe temporal patterns of larval density and cohort development. Water quality data for are also provided for a deep-water station where larvae were sampled. Our observations indicate that, while populations of adult mussels have declined by about 20% since the year 2000, adult densities and the supply of larvae are still moderately high and the species seems to be well established in Conesus Lake.