6,789 research outputs found
Biological Assessments of Six Selected Fishes, Amphibians, and Mussels in Illinois
ID: 8758; issued November 1, 1996INHS Technical Report prepared for Illinois Department of Natural Resources, Division of
Natural Heritag
Survey of Rock River Mussels (Mollusca: Unionidae) at the Illinois Route 2 (FAP 742) Bridge South of Grand Detour, Lee and Ogle Counties, Illinois. IDOT Job Number P-92-008-83
ID: 8592; issued December 31, 1986INHS Technical Report prepared for Illinois Department of Transportatio
Mollusca of the Illinois River, Arkansas
The Illinois River is in the Ozark region of northwestern Arkansas and eastern Oklahoma. A survey of the Illinois River in Arkansas produced nine species and one morphological subspecies of gastropods, three species of sphaeriid clams, and 23 species of unionid mussels. Museum records resulted in another two species and an ecophenotype of the Unionidae. This represents the first published survey of molluscan species from the Illinois River in Arkansas
The Effect of Natural Dissolved Organic Carbon on the Acute Toxicity of Copper to Larval Freshwater Mussels (\u3cem\u3eGlochidia\u3c/em\u3e)
The present study examined the effect of dissolved organic carbon (DOC), both added and inherent, on Cu toxicity in glochidia, the larvae of freshwater mussels. Using incremental additions of natural DOC concentrate and reconstituted water, a series of acute copper toxicity tests were conducted. An increase in DOC from 0.7 to 4.4 mg C/L resulted in a fourfold increase (36–150 μg Cu/L) in the 24-h median effective concentration (EC50) and a significant linear relationship (r2=0.98, p=0.0008) between the DOC concentration and the Cu EC50 of Lampsilis siliquoidea glochidia. The ameliorating effect of added DOC on Cu toxicity was confirmed using a second mussel species, the endangered (in Canada) Lampsilis fasciola. The effect of inherent (i.e., not added) DOC on Cu toxicity was also assessed in eight natural waters (DOC 5–15 mg C/L). These experiments revealed a significant relationship between the EC50 and the concentration of inherent DOC (r2=0.79, p=0.0031) with EC50s ranging from 27 to 111 μg Cu/L. These laboratory tests have demonstrated that DOC provides glochidia with significant protection from acute Cu toxicity. The potential risk that Cu poses to mussel populations was assessed by comparing Cu and DOC concentrations from significant mussel habitats in Ontario to the EC50s. Although overall mean Cu concentration in the mussel’s habitat was well below the acutely toxic level given the concentration of DOC, episodic Cu releases in low DOC waters may be a concern for the recovery of endangered freshwater mussels. The results are examined in the context of current Cu water quality regulations including the U.S. Environmental Protection Agency’s (U.S. EPA) biotic ligand model
Cases of hermaphroditism in the Ukrainian populations of Unionidae (Bivalvia)
The aim of the research is to establish sex status of Unionidae family specimens with different method
Distribution and Status of Rare and Endangered Mussels (Mollusca: Margaritiferidae, Unionidae) in Arkansas
Knowledge of the distribution and population status of freshwater bivalves occurring in Arkansas has increased markedly during the past decade. Sufficient data has become available to delineate species which are rare and/or endangered within the state. Historical and recent records from Arkansas exist for four mussels currently listed as federally endangered species: the fat pocketbook (Potamilus capax), the pink mucket (Lampsilis orbiculata), Curtis\u27 pearly mussel (Epioblasma florentina curtisi), and the turgid-blossom pearly mussel (Epioblasma turgidula). Ten additional mussels which occur or were thought to occur in Arkansas are being considered for federal protection by the United States Fish and Wildlife Service. Several other taxa may warrant protective status
Continuous reproduction of Sinanodonta woodiana (Lea,1824) females : an invasive mussel species in a female-biased population
The reproductive activity of females of the Chinese pond mussel (Sinanodonta woodiana) was investigated in a European population inhabiting cooling water. The study used histological and stereological methods to determine gonad structure, changes in reproductive follicles during gametogenesis, oocyte development, glochidia structure and brooding periods. Water in the channel of the "Dolna Odra" power plant did not freeze during the winter, and its mean annual temperature was 18.4^{\circ}C. The population sex ratio was female-biased (\chi^{2} = 25.70, df = 1, p < 0.0001). Ovaries in mussels were formed by reproductive follicles. Previtellogenic and vitellogenic oocytes were attached to the follicle wall via the cytoplasmic stalk, and mature ovulated oocytes were present in the follicle lumen. Individuals with mature oocytes in gonads were present over the whole two-year study period, which indicates the continuous activity of gonads. Hooked glochidia had a larval thread. Females incubated the offspring in gill marsupia of outer demibranchs and were characterized by multiple tachytictic brooding periods. All gravid individuals presented mature and spent stages of gonadal development. The study provides the first direct information about the reproductive dynamics of this invasive species outside its original Asiatic range
THE DISTRIBUTION AND ECOLOGY OF DREISSENA POLYMORPHA AND D. BUGENSIS (MOLLUSCA: BIVALVIA: DREISSENIDAE) IN WATER RESERVOIRS AND WATER CURRENTS OF UKRAINE WHEN DWELLING TOGETHER WITH UNIONIDS (MOLLUSCA: BIVALVIA: UNIONIDAE)
In May-October 2008-2009 208 points within the basins of the Dnieper, the Prypyat, the Western and Southern Bug, the Siversky Donets, the Dniester, the lower Danube, rivers of the Crimea and the Northern Azov territory of Ukraine were investigated. Dreissena specimens were collected in the silted bottom in case they use living unionidae shells as the habitat substrate
Invasive algae, plant, bivalve and crustacean species along the Hungarian Danube section: arrival time, colonisation characteristics, relative importance
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