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Changes in the distribution of freshwater mussels (Unionidae) in the upper Susquehanna River basin, 1955-1997

posted on 2023-07-24, 17:34 authored by Dave StrayerDave Strayer

These data describe the freshwater mussel (Unionidae) communities and environmental conditions in streams and rivers of the Susquehanna River basin in New York State in 1996-1997.


The Nature Conservancy

New York State Department of Environmental Conservation


Geographic description

streams and rivers in the Susquehanna River basin in New York State

Time period



This study was a survey of freshwater mussel (Unionidae) communities at 115 sites on streams and rivers in the Susquehanna River basin in New York state. 67 of these sites were resurveys of sites that had been surveyed by others in 1955-1965, while 48 sites had not been surveyed previously. We surveyed sites during periods of low water in the summers of 1996 and 1997, either wading or snorkeling to conduct visual surveys of mussels. We did not excavate or sieve sediments. We searched each site until we believed that we had found all of the species living there, or had searched all suitable, accessible habitat. We examined all likely habitats, and searched for spent shells on the streambank and in muskrat middens. Typically, we covered 100-500 m of stream length, and spent 0.5-2.5 person-h searching a site. Living mussels were identified, measured in length to the nearest cm using a ruler, and replaced into the stream bottom. We also recorded the presence and condition of dead mussel shells. Vouchers (typically spent shells) that we collected are deposited in the New York State Museum in Albany. We also collected environmental data. At each site, we recorded the width of the riparian zone (i.e., the width of the zone along the stream with more or less natural vegetation) and land use beyond the riparian zone. We also assessed visibility as the depth to which our yellow, 11.5cm x 19 cm Rite-in-the-Rain field books could be seen: < 50 cm, ca, 50 cm, 50-100 cm, ca. 100 cm, or > 100 cm. In addition, at the 67 historical sites, we collected water samples at three times (May, Jul.-Aug. and Sept.) during low water in 1996. These samples were filtered (GF/F filters) and acidified to pH = 2 with heavy-metal grade sulfuric acid immediately after collection. We then combined the three samples from each site, and measured calcium (Perkin-Elmer 2380 atomic absorption spectrometer), nitrate-N + nitrite-N (Alpkem 500 series autoanalyzer)(henceforth called nitrate-N), reactive phosphorus (Alpkem 500 series autoanalyzer) and organic carbon (Shimadzu TOC-5050 total organic carbon analyzer).

Location of field samples or specimens

New York State Museum, Albany

Taxonomic species or groups

Bivalvia, Unionidae, Elliptio complanata, Lasmigona compressa, Lasmigona subviridis, Anodontoides ferussacianus, Pyganodon cataracta, Alasmidonta undulata, Alasmidonta marginata, Alasmidonta varicosa, Strophitus undulatus, Lampsilis radiata, Lampsilis cariosa, Utterbackia imbecillis

Secondary Data Contact

Data Sharing Statement

The Cary Institute of Ecosystem Studies furnishes data under the following conditions: The data have received quality assurance scrutiny, and, although we are confident of the accuracy of these data, Cary Institute will not be held liable for errors in these data. Data are subject to change resulting from updates in data screening or models used.