Keywords
freshwater mussels, zebra mussels, individual based, population dynamics, competition
Start Date
1-7-2006 12:00 AM
Abstract
The family Unionidae (freshwater mussels) is geographically diverse with species found worldwide; their greatest diversity is found in North America. Zebra mussels (Dreissena polymorpha) are an exotic species introduced into North America in the 1980’s that has since become a threat to economic interests and native mussel species in the region. IIHR-Hydroscience and Engineering and WL|Delft Hydraulics are developing a numerical model of mussel population dynamics for the purpose of analyzing alternative management strategies of zebra mussels and Unionidae in the Upper Mississippi River (UMR). The Mussel Dynamics Model (MDM) simulates interaction of mussels and the hydraulic environment. This paper describes the approach taken in the MDM. Environmental conditions are defined by water quality parameters and using a 3D hydrodynamics model to solve for flow conditions. Incorporated is a habitat suitability index model (HSI) that uses basic rules of species tolerance to various environmental conditions, including host fish distributions. This information along with the biological and ecological characteristics of mussels is used in an individual based population dynamics model that simulates change of stage, competition, feeding and growth, reproduction, dispersal and settlement, motion, and mortality. The MDM has been run on a reach of pool 16 in the Mississippi River with positive results. Food competition between native and invasive species was simulated and the results are in agreement with observed survival rates of unionids reported in the literature. Currently efforts are underway to redesign the model to facilitate portability, to decrease computational time, allow for larger grid sizes, and to develop a user friendly interface. The HSI has been translated into C with an increase in processing speed and the ability to handle millions of grid points, a significant improvement over the original code.
Ecohydraulics in the Mississippi River: Freshwater Mussel Dynamics Model
The family Unionidae (freshwater mussels) is geographically diverse with species found worldwide; their greatest diversity is found in North America. Zebra mussels (Dreissena polymorpha) are an exotic species introduced into North America in the 1980’s that has since become a threat to economic interests and native mussel species in the region. IIHR-Hydroscience and Engineering and WL|Delft Hydraulics are developing a numerical model of mussel population dynamics for the purpose of analyzing alternative management strategies of zebra mussels and Unionidae in the Upper Mississippi River (UMR). The Mussel Dynamics Model (MDM) simulates interaction of mussels and the hydraulic environment. This paper describes the approach taken in the MDM. Environmental conditions are defined by water quality parameters and using a 3D hydrodynamics model to solve for flow conditions. Incorporated is a habitat suitability index model (HSI) that uses basic rules of species tolerance to various environmental conditions, including host fish distributions. This information along with the biological and ecological characteristics of mussels is used in an individual based population dynamics model that simulates change of stage, competition, feeding and growth, reproduction, dispersal and settlement, motion, and mortality. The MDM has been run on a reach of pool 16 in the Mississippi River with positive results. Food competition between native and invasive species was simulated and the results are in agreement with observed survival rates of unionids reported in the literature. Currently efforts are underway to redesign the model to facilitate portability, to decrease computational time, allow for larger grid sizes, and to develop a user friendly interface. The HSI has been translated into C with an increase in processing speed and the ability to handle millions of grid points, a significant improvement over the original code.
