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Full-Text Articles in Physical Sciences and Mathematics
Recent Changes In Density, Biomass, Recruitment, Size Structure, And Nutritional State Of Dreissena Populations In Southern Lake Michigan, Thomas F. Nalepa, David L. Fanslow, Steven A. Pothoven
Recent Changes In Density, Biomass, Recruitment, Size Structure, And Nutritional State Of Dreissena Populations In Southern Lake Michigan, Thomas F. Nalepa, David L. Fanslow, Steven A. Pothoven
United States Department of Commerce: Staff Publications
Trends in density, biomass, population structure, and nutritional state of Dreissena polymorpha and Dreissena rostriformis bugensis were examined in southern Lake Michigan between the 1990s and 2008. Density and biomass of D. polymorpha increased to a peak in the early 2000s and then declined. In contrast, D. rostriformis bugensis was first found in the southern basin in 2001 and has continued to increase in density or biomass at all depths ever since. In 2008, maximum mean density of D. rostriformis bugensis occurred at 16–30 m (19,000/m2), but maximum biomass (AFDW) occurred at 31–50 m (43.9 g/m2). …
First Finding Of The Amphipod Echinogammarus Ischnus And The Mussel Dreissena Bugensis In Lake Michigan, Thomas F. Nalepa, Don W. Schloesser, Steve A. Pothoven, Darryl W. Hondorp, David L. Fanslow, Marc L. Tuchman, Guy W. Fleischer
First Finding Of The Amphipod Echinogammarus Ischnus And The Mussel Dreissena Bugensis In Lake Michigan, Thomas F. Nalepa, Don W. Schloesser, Steve A. Pothoven, Darryl W. Hondorp, David L. Fanslow, Marc L. Tuchman, Guy W. Fleischer
United States Department of Commerce: Staff Publications
The first finding of the amphipod Echinogammarus ischnus and the mussel Dreissena bugensis in Lake Michigan is documented. These two species are widespread and abundant in the lower lakes, but had not yet been reported from Lake Michigan. E. ischnus is generally considered a warmwater form that is typically associated with hard substrates and Dreissena clusters in the nearshore zone. Along the eastern shoreline of Lake Michigan, this species was present at rocky, breakwall habitats along the entire north-south axis of the lake. Although not abundant, this species was also found at soft-bottomed sites as deep as 94 m in …
Changes In The Freshwater Mussel Community Of Lake St. Clair: From Unionidae To Dreissena Polymorpha In Eight Years, Thomas F. Nalepa, David J. Hartson, Gerald W. Gostenik, David L. Fanslow, Gregory A. Lang
Changes In The Freshwater Mussel Community Of Lake St. Clair: From Unionidae To Dreissena Polymorpha In Eight Years, Thomas F. Nalepa, David J. Hartson, Gerald W. Gostenik, David L. Fanslow, Gregory A. Lang
United States Department of Commerce: Staff Publications
To determine density changes in both the zebra mussel, Dreissena polymorpha, and native mussels, Unionidae, in Lake St. Clair, surveys were conducted in 1990, 1992, and 1994 and compared to a similar survey in 1986 when no D. polymorpha was found. Collection methods were the same each year; divers used the quadrat method to collect 10 replicate samples at 29 sites located throughout the lake. The total number of unionids collected declined from 281 in 1986, to 248 in 1990, 99 in 1992, and 6 in 1994, while the number of species collected in each of the four respective …
Filtration Rates Of The Zebra Mussel (Dreissena Polymorpha) On Natural Seston From Saginaw Bay, Lake Huron, David L. Fanslow, Thomas F. Nalepa, Gregory A. Lang
Filtration Rates Of The Zebra Mussel (Dreissena Polymorpha) On Natural Seston From Saginaw Bay, Lake Huron, David L. Fanslow, Thomas F. Nalepa, Gregory A. Lang
United States Department of Commerce: Staff Publications
Filtration rates of the zebra mussel (Dreissena polymorpha) on natural seston from two different regions in Saginaw Bay were determined on a monthly basis from April to October in 1992 and 1993. The two regions represent contrasting trophic conditions, with the inner bay more eutrophic than the outer bay. Mean filtration rate was 16.2 mL/mg/h (range 4.0 to 40.7 mL/mg/h) over the entire 2-year period. Filtration rates on seston from the inner bay were significantly lower than rates on seston from the outer bay in 1992, but no differences were apparent in 1993. Lower rates were attributed to …
Initial Colonization Of The Zebra Mussel (Dreissena Polymorpha) In Saginaw Bay, Lake Huron: Population Recruitment, Density, And Size Structure, Thomas F. Nalepa, James A. Wojcik, David L. Fanslow, Gregory A. Lang
Initial Colonization Of The Zebra Mussel (Dreissena Polymorpha) In Saginaw Bay, Lake Huron: Population Recruitment, Density, And Size Structure, Thomas F. Nalepa, James A. Wojcik, David L. Fanslow, Gregory A. Lang
United States Department of Commerce: Staff Publications
The various life stages of the zebra mussel (Dreissena polymorpha) were examined during the initial years (1991-93) of the mussel's invasion into Saginaw Bay, Lake Huron. Yearly trends in densities of larvae, newly-settled juveniles, and adults were poorly related. Larval densities were lowest in 1991 and increased each year, but the number of settled juveniles was highest in 1991. Adults increased between 1991 and 1992 and then declined in 1993. Mean adult densities at sites with hard substrates were 11,700,33,200, and 4,1001m2 in each of the 3 years, respectively. Year-to-year variation at individual sites was high and likely …
Nutrient Changes In Saginaw Bay, Lake Huron, After The Establishment Of The Zebra Mussel (Dreissena Polymorpha), Thomas H. Johengen, Thomas F. Nalepa, Gary L. Fahnenstiel, Greg Goudy
Nutrient Changes In Saginaw Bay, Lake Huron, After The Establishment Of The Zebra Mussel (Dreissena Polymorpha), Thomas H. Johengen, Thomas F. Nalepa, Gary L. Fahnenstiel, Greg Goudy
United States Department of Commerce: Staff Publications
Concentrations of particulate and dissolved nutrients in Saginaw Bay, Lake Huron, were examined relative to zebra mussel colonization which occurred summer 1991. The magnitude and spatial pattern of changes indicate that mussels had a significant impact on nutrients in Saginaw Bay. Annual means for total suspended solids, particulate organic carbon, particulate phosphorus, and particulate silica in the inner bay were significantly lower in 1992 and 1993 (post-zebra mussel) than in 1991 (pre-zebra mussel). Annual means decreased from 11.5 mg L-1, 1.45 mg C L-1 (121 µM), 20.4 µg P L-1(0.66 µM), and 1.52 mg SiO …
Effects Of Zebra Mussel (Dreissena Polymorpha) Colonization On Water Quality Parameters In Saginaw Bay, Lake Huron, Gary L. Fahnenstiel, Gregory A. Lang, Thomas F. Nalepa, Thomas H. Johengen
Effects Of Zebra Mussel (Dreissena Polymorpha) Colonization On Water Quality Parameters In Saginaw Bay, Lake Huron, Gary L. Fahnenstiel, Gregory A. Lang, Thomas F. Nalepa, Thomas H. Johengen
United States Department of Commerce: Staff Publications
A large-scale study of Saginaw Bay was initiated in 1990 and continued through 1993 to examine the effects of the zebra mussel colonization which began in summerlfall 1991. Saginaw Bay responded quickly to the zebra mussel colonization, as fall 1991 values of chlorophyll were similar to 1992 and 1993 values. In inner Saginaw Bay, where most zebra mussels were found, chlorophyll, kPAR, and total phosphorus values decreased, and Secchi disk depth increased during the study period, regardless of the presence or absence of zebra mussels at a specific station. At outer bay control stations no significant differences were found for …
Seasonal And Annual Variation In Weight And Biochemical Content Of The Zebra Mussel, Dreissena Polymorpha, In Lake St. Clair, Thomas F. Nalepa, Joann F. Cavaletto, Mark Ford, Wendy M. Gordon, Marijo Wimmer
Seasonal And Annual Variation In Weight And Biochemical Content Of The Zebra Mussel, Dreissena Polymorpha, In Lake St. Clair, Thomas F. Nalepa, Joann F. Cavaletto, Mark Ford, Wendy M. Gordon, Marijo Wimmer
United States Department of Commerce: Staff Publications
Zebra mussels, Dreissena polymorpha, were collected monthly from April/May to November in 1990 and 1991 from two sites in Lake St. Clair. The sites were characterized by relatively high and low mussel densities. The following variables were measured: ash-free dry weight (AFDW) per unit shell length (SL), lipid content and classes, carbon content, and nitrogen content. Mussels from the high-density site had a lower AFDW:SL relationship, lower lipid content, and a lower C:N ratio than mussels from the low-density site. Seasonal trends in these variables were consistent between sites and years. AFDW:SL, lipid, and carbon content were highest in …