Quantifying potential propagule pressure of aquatic invasive species from the commercial shipping industry in Canada.
We quantify and compare different measures of potential propagule pressure (PPP) of aquatic invasive species (AIS) from commercial vessels in Canada. We used ship arrivals and ballast water discharge volumes as proxies for PPP from ballast water organisms, and wetted surface area (WSA) as a proxy for hull fouling PPP, to determine their relative contributions to total PPP. For three regions studied, PPP proxies correlated significantly across ports and some vessel categories. Relative contributions of ship arrivals, ballast discharge, and WSAs to PPP, evidenced by non-significant correlations across these measures, varied across regions, ports, vessel types, and seasons. Flow-through (dominant on east and west coasts) and empty-refill (in Great Lakes-St. Lawrence region) were the major ballast water exchange methods employed by the vessels surveyed. These methods have different biological efficacy for AIS removal, influencing PPP. Our study illustrates benefits and limitations of using different PPP proxies to estimate invasion risk.
Institute for Resources, Environment & Sustainability, University of British Columbia, 438-2202 Main Mall, Vancouver, BC, Canada V6T 1Z4. veronica.lo@alumni.ubc.ca
Veronica B
VB
Lo
Colin D
CD
Levings
Kai M A
KM
Chan
D000818:Animals; D001267:Atlantic Ocean; D002170:Canada; D004784:Environmental Monitoring; D058865:Introduced Species; D060106:Lakes; D008962:Models, Theoretical; D010140:Pacific Ocean; D010571:Pest Control; D045483:Rivers; D012767:Ships