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GLERL, Conference Room 105
2205 Commonwealth Blvd
Ann Arbor, MI


Thursday, June 14, 10:30 am

"Eastern brook trout ecology: a synthesis of field, laboratory and modeling studies "

Dr. Kyle J. Hartman
Associate Professor, Wildlife & Fisheries Program,
West Virginia University

Appalachian headwater streams are high gradient, cold water systems historically dominated by brook trout (Salvelinus fontinalis). These systems are subject to many anthropogenic and natural perturbations such as acid deposition, acid mine drainage, sedimentation and deforestation, and floods and drought. In 1998 we began studying various aspects of the ecology and population dynamics of brook trout. Among these studies included development of bioenergetic models for brook trout, evaluation of suspended and deposited sediment upon feeding and reproductive success, habitat use, and manipulative studies. These studies improved our understanding of brook trout ecology. However, large scale changes in habitat quality and brook trout populations have occurred since the early 1900’s, yet little data is available detailing habitat and population responses over time. Therefore, in 2002 we initiated a long-term study of 25 headwater streams in West Virginia to study the spatial and temporal variability of stream habitat and brook trout populations in the Central Appalachian Mountains. Such long-term studies are needed to identify limiting and controlling factors of brook trout in this region and the relative impacts of each upon overall population resilience. Our analyses have discovered strong stock-recruit relationships in the most productive geologies, while other factors such as habitat and water quality appear to limit populations in most other geologies. Stable populations occur where habitat is most stable. Knowledge of these factors within the context of land-use practices and determination of the habitat attributes controlling the abundance of all life stages of brook trout will enable better land-use and restoration guidelines to be established for the region.

Thursday, June 21, 10:30 am

"Dreissenids Mussel into the Great Lakes Offshore Benthic Zone "

Dr. Stephan Lozano
Ecologist, NOAA-GLERL

Dreissenids are successful invaders in the Great Lakes. There is ample evidence that dreissenids have made a major impact on the Great Lakes. The benthic filter feeders are capable of attaching to both soft and hard substrates and filter large portions of the nearshore waters. The conceptual model of a nearshore phosphorus shunt has been used to describe the consequences of ecosystem engineering by dreissenids in the nearshore. In my presentation, I will describe the status of invasive dreissenid mussels and the native amphipods, Diporeia, in Lake Ontario over the last 20 years. The two most common hypotheses for the decline of Diporeia in the Great Lakes are food limitation and a toxin/pathogen associated with dreissenid pseudofeces. The Diporeia decline in deep waters preceded the expansion of D. bugensis to these depths and suggests that shallow dreissenid populations remotely influence profundal habitats. This pattern of decline is consistent with mechanisms that act from some distance including nearshore dreissenid grazing and downslope transport of pseudofeces. Other evidence from recent lake surveys suggest that the impact of dreissenids from phosphorus removal may also play a major role in the displacement of Diporeia in offshore waters.

For directions, see
David F. Reid, Ph.D.
Director, NOAA National Center for Research on 
Aquatic Invasive Species (NCRAIS)
Senior Research Scientist, Nonindigenous Species Program
U.S. Department of Commerce
National Oceanic and Atmospheric Administration
Great Lakes Environmental Research Laboratory
2205 Commonwealth Blvd.
Ann Arbor, MI  48105-2945
Voice: 734-741-2019
FAX: 734-741-2055
GLERL home page:
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