Larval Dispersal of the Nonnative Zebra Mussel in the Saint Lawrence Estuary: A Modeling Study

EPA Grant Number: U916232
Title: Larval Dispersal of the Nonnative Zebra Mussel in the Saint Lawrence Estuary: A Modeling Study
Investigators: Simons, Rachel D.
Institution: Stanford University
EPA Project Officer: Lee, Sonja
Project Period: January 1, 2003 through January 1, 2006
Project Amount: $92,070
RFA: STAR Graduate Fellowships (2003) Recipients Lists
Research Category: Academic Fellowships , Fellowship - Oceanography and Coastal Processes , Aquatic Ecosystems


The nonindigenous zebra mussel (Dreissena polymorpha) was first discovered in Lake Saint Clair in 1988. Originally from eastern Europe, the zebra mussel spread throughout the Great Lakes and adjacent waterways, causing extensive damage to the ecosystem. By 1991, the zebra mussel had spread to the Saint Lawrence Estuary (SLE) in Canada. The zebra mussel is a serious threat to any ecosystem it invades for three reasons. First, it spreads quickly because of its free-swimming larval stage; second, it establishes large populations rapidly; and third, as a filter feeder, it alters the flow of energy through the food web. Consequently the major problems resulting from a zebra mussel invasion are biofouling of water intake pipes and extinction of native species. The key to controlling the spread of the zebra mussel is understanding how its free-swimming larvae, called veligers, disperse and settle. The objective of this research project is to investigate and understand the dispersal of zebra mussel veligers in the SLE by linking the hydrodynamics of the SLE with larval biology through three-dimensional computer modeling.


This research will focus on the dispersal of zebra mussel veligers in a particularly vulnerable and ecologically important region of the SLE: the estuarine transition zone (ETZ). The physical-biological computer model of the ETZ used for this research consists of two parts: a circulation model and a zooplankton transport model. The circulation model is a three-dimensional Eulerian hydrodynamic model (TRIM3D) driven by the wind, tides, and freshwater outflow. The zooplankton transport model is a three-dimensional Lagrangian particle-tracking model, which simulates zooplankton movement in the three-dimensional flow of the circulation model. The circulation model is calibrated using hydrodynamic field data. Using this model, I will explore the physical and biological mechanisms that control the transport and retention of zebra mussel veligers in the ETZ. My results will ultimately help control the spread of this and similar invasive species.

Supplemental Keywords:

fellowship, Saint Lawrence Estuary, SLE, estuarine transition zone, ETZ, zebra mussel, Dreissena polymorpha, computer modeling, invasive species, zebra mussel veligers, TRIM 3D, particle-tracking model, circulation model, hydrodynamic model.

Progress and Final Reports:

  • 2003
  • 2004
  • Final