Science Advisory Report 2015/019
Risk assessment of alternate ballast water exchange zones for vessel traffic to the eastern Canadian Arctic
Summary
- Transport Canada asked DFO for advice on current and potential exchange zones for ballast water in the eastern Canadian Arctic.
- Scientifically defensible advice was based on modeling the relative risks of ballast exchange at different locations along major shipping routes in the eastern Arctic. Dispersion model results were robust to variation in the weighting of the physical and chemical environmental characteristics of receiving habitats and consistently identified the same regions as having higher relative risk.
- The existing ABWEZs in Lancaster Sound and Hudson Strait are among the areas of highest relative overall risk associated with ballast water-mediated aquatic nonindigenous species (NIS). It is recommended that these zones be removed from current regulations and replaced with more appropriate ones.
- It is recommended that ABWEZs within the eastern Arctic be situated offshore of the 1000 m depth contour in waters between latitudes 57 and 75°N, and longitudes 56 and 73°W (Figure 1).
- To further mitigate risks from organisms in the ballast sediment, it is recommended that vessels entering the Canadian eastern Arctic from beyond the Exclusive Economic Zone (EEZ) not in ballast flush their residuals from the ballast tanks prior to entering waters under Canadian jurisdiction. An ABWEZ should be used as a last resort.
- There are currently no regulations for ballast water exchange for vessels operating within the EEZ. Given the potential for transfer of both indigenous and established NIS from southern Canada (and northeastern United States) by these vessels, the recommended ABWEZs would also be appropriate for ballast water exchange and flushing for vessels arriving from southern Canada regardless of whether they have taken on fresh- or marine ballast water. Recognizing operational constraints of vessels coming from southern Canada, further research is needed to assess options for exchange zones closer to shore.
- Under the current regulations Canada does not require reporting of the origin of ballast water for vessels operating within the EEZ. Such knowledge would improve our abilities to understand ballast mediated NIS introductions. It is recommended that these data be acquired.
This Science Advisory Report is from the November 20-21, 2013 Risk Assessment of Alternate Ballast Water Exchange Zones for vessel traffic to the Eastern Canadian Arctic. Additional publications from this meeting will be posted on the DFO Science Advisory Schedule as they become available.
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