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1	The role of hydrodynamics in determining the habitat selection of juvenile unionid mussels Glover, Sarah Kathryn 23 January 2013 (has links) The factors influencing habitat selection by juveniles of species within the family Unionidae (i.e., unionids), between post-larval detachment from a fish host and burrowing into the substratum, are largely unknown. Bed shear stress (τw) has been proposed as a critical factor. A laboratory wall jet apparatus generated τw to assess the response of juvenile Epioblasma triquetra, Villosa iris, Lampsilis fasciola, and Ligumia nasuta. The relationships between juvenile unionids, τw, and chemical and physical parameters were also examined in the field. There was a significant relationship between unionid resuspension and τw in the laboratory (resuspension when τw > 0.26 Pa), and adhesion behaviour required greater critical τw. Near-bed velocity and D50 grain size predicted sphaeriid clam density (a proxy for juvenile unionids) in the field. Laboratory experiments confirmed predictions that juvenile unionids cannot establish beyond a critical τw, demonstrating the importance of hydrodynamics in dispersal and for developing unionid conservation measures. / NSERC and Species At Risk Research Fund Ontario (MNR) to J.D.A. shear stress hydrodynamics conservation adhesion life history juvenile unionid mussel post-settlement dispersal
2	Abundance and Distribution of Early Life Stage Blue Crabs (Callinectes sapidus) in Lake Pontchartrain Lyncker, Lissa 07 August 2008 (has links) I conducted a 12-month study of near-shore habitats in Lake Pontchartrain to assess spatiotemporal variation in the abundance of early life stage blue crabs (Callinectes sapidus). Collections were made using a 1 m2 throw trap and data showed that C. sapidus numbers varied over time and among sites. Two recruitment events occurred during the study. During the first recruitment in May-June, C. sapidus entered Lake Pontchartrain via the Inner Harbor Navigational Canal. In September-October, C. sapidus entered the Lake Pontchartrain via the Rigolets and Chef passes. My data suggest that C. sapidus utilize water circulation within the Lake Pontchartrain as a means of transportation throughout the estuary. MODerate-resolution Imaging Spectroradiometer (MODIS) 250 m data were analyzed to gain a large-scale view of suspended sediments patterns within Lake Pontchartrain and quantify water movement. Field sampling along with remote sensing proved to be beneficial when assessing estuarine-wide C. sapidus post-larval dispersal processes. Callinectes sapidus blue crab crab migration crab transport Callinectes sapidus transport nursery habitat dispersal post-larval dispersal post-settlement dispersal recruitment SAV Lake Pontchartrain mass water movement remote sensing MODIS 250 m data MODIS 250 m satellite images estuarine dependent species suspended sediment

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The role of hydrodynamics in determining the habitat selection of juvenile unionid mussels

Abundance and Distribution of Early Life Stage Blue Crabs (Callinectes sapidus) in Lake Pontchartrain