Date Published: February 7, 2019
Publisher: Public Library of Science
Author(s): Jesica Goldsmit, Christopher McKindsey, Philippe Archambault, Kimberly L. Howland, Judi Hewitt.
Climate change is impacting environmental conditions, especially with respect to temperature and ice cover in high latitude regions. Predictive models and risk assessment are key tools for understanding potential changes associated with such impacts on coastal regions. In this study relative ecological risk assessment was done for future potential introductions of three species in the Canadian Arctic: periwinkle Littorina littorea, soft shell clam Mya arenaria and red king crab Paralithodes camtschaticus. These species occur in locations connected to Canadian Arctic ports through shipping and have the potential to be introduced via ballast water discharge. The methodology proposed in this study is unique in the sense that it considers not only ballast water origin, but also the distribution of the species being assessed and the sensitivity of the receiving habitat. It combines detailed information (ballast water source of each tank, transit time, time of the year when the water is released, environmental suitability of receiving habitat, impact, and habitat sensitivity) in order to assess ecological risk. Through the use of this approach it is highlighted that domestic discharge events pose a higher relative overall risk on a vessel-specific and cumulative annual bases than international discharges. The main ports of Deception Bay and Churchill were classified as being at moderate to high relative risk for L. littorea and M. arenaria, especially from domestic vessels, while relative overall risk for P. camtschaticus was low for international vessels and null for domestic vessels due to few ships transiting from its range of distribution to Canadian Arctic ports. This work can serve as an approach to help build a list of potential high risk species–a “grey” watch list–for the Canadian Arctic, and provides useful information for consideration in future decision making actions such as the identification of high risk pathways, species and ports.
Invasive species and global warming are among the most serious drivers of global environmental change and threaten marine biodiversity [1–3]. Successful establishment of an invasive species depends upon it completing a series of transitions, each with independent probabilities of failure [4, 5]. Vectors must uptake, transport, and deliver a sufficient number of viable propagules to an area outside of the species’ historic range. These individuals must be capable of surviving, reproducing, and establishing under ambient physico-chemical and biological-ecological conditions .
This relative risk assessment provides information on the potential risk of introduction, establishment, and impact for three species that are not, to our knowledge, currently present in the Canadian Arctic, but for which there is likely suitable habitat for their survival and establishment in the region. The methodology used in the present study is unique in that it considers ballast water sources and the distribution of NIS (i.e., the potential availability of NIS propagules in ballast water sources). Moreover, it evaluates the relative risk of the combination of each port, year, and species considered, thus allowing for a more realistic, comprehensive ecological risk assessment at the species-level. The results show that ports in the Canadian Arctic have likely been exposed to propagules of NIS that are established in connected ports or BWE locations, especially via domestic vessels. Although the current probabilities of establishment for the species considered in this study are generally low, it is important to note that the consequence of their establishment ranges from moderate to high for most ports considered in the study. Thus, if vessel-specific ballast water discharges increase in the future, so too will relative overall risk. This is a plausible scenario given that shipping activity in the Canadian Arctic is expected to increase in the future due to the opening of seasonal trading routes through the North West Passage and increasing resource exploitation in the region [25, 27, 28]. The level of risk could be also influenced by projected increases in the habitat suitability for these species in the region as a result of global climate change .