Predicting the secondary spread of aquatic invasive species through ballast water and recreational boating in the Great Lakes basin
Recent biological invasions (e.g., Hemimysis anomala, VHS) within the Great Lakes basin (GLB) emphasize the need for early detection and rapid response protocols to effectively manage the secondary spread of aquatic invasive species (AIS). Determining appropriate management actions following initial discovery of an AIS requires: 1) knowledge of the environmental niche that AIS occupy; 2) the locations of suitable environmental niches within the GLB; and, 3) the probability of AIS to spread to, and colonize within, such locations. Although AIS dispersal may occur naturally, such as through larval drift, vectors such as ballast water and recreational boating may surpass background rates of natural dispersal, resulting in rapid colonization of suitable habitat within the GLB. Currently, there are no regulations to minimize the movement of ballast water (via Lakers) or to minimize the spread of AIS through recreational boating within the GLB. To effectively minimize the spread and establishment of newly discovered AIS, early detection monitoring, and subsequent rapid response if detected, need to be undertaken in locations where they are most likely to spread. Therefore, objectives are: 1) To determine the probability of spread and establishment between all possible pairs of ports based on vector strength (ballast, recreational boats) and environmental similarity. H1: Probability of spread and establishment can be predicted by vector movement patterns and environmental similarity between ports; and, 2) To develop an interactive tool that identifies probability of spread from a port with a newly discovered AIS to all other GLB ports for the purpose of directing early detection monitoring to highest risk ports. To determine the probability of movement of ballast water or recreational vessels within GLB, spatial interaction models will be developed that incorporate standardized data (e.g., shipping distance between ports, ballast volume, port size) available for Lakers for the entire GLB including the St. Lawrence River (for description of data see Rup et al. (including Bailey) 2010) and being collected in 2010 for recreational boating on the Canadian side of the Great Lakes. Additional data sets will be used if made available for this project. Models will generate an interaction matrix between ports describing the relative probability and magnitude of ballast and recreational boat exchange as a measure of vector strength. To determine the environmental similarity between ports, similarity will be calculated using multivariate statistics (e.g., principal components analysis) based on data (e.g. climate, water temperature, productivity, substrate) compiled from a variety of sources including Globallast, NOAA, Great Lakes GIS, and DFO. These models will be tested through retrospective analyses compared to the known spread sequence and environmental niches of established AIS such as Round Goby, Threespine Stickleback, Cercopagis and Zebra Mussel. The models will be applied to AIS with currently limited distributions in the GLB, such as Ruffe, Fourspine Stickleback and Hemimysis, and species not yet in the GLB, such as Asian carps, to identify ports to which they are most likely to spread.