Many factors may determine whether a species is able to survive and reproduce in a new region. For aquatic organisms, temperature and salinity play major roles in determining where a species can live1,2. Scientists think this might be especially true in polar systems such as the Bering Sea, because many organisms are not adapted to life in cold water3.
We examined the potential for non-native taxa to survive and reproduce within Bering Sea by comparing species’ environmental tolerances to temperature and salinity values in the Bering Sea. We obtained species’ data when conducting literature searches for our ranking system. Data for the Bering Sea were derived from three Regional Ocean Modeling Systems4 (ROMS), which provide weekly temperature and salinity values across the Bering Sea.
Can non-native species currently survive in the Bering Sea?
Of the 42 taxa we considered, at least 33 are predicted to have year-round suitable habitat in the Bering Sea. The Aleutian Islands and the northwestern Alaska Peninsula were suitable for the greatest number of species. Areas currently unsuitable to non-native species, such as Norton Sound, experience below-freezing water temperatures and/or sea ice cover during the winter months.
Habitat suitability in a changing climate
Oceanographic conditions in the Bering Sea are changing rapidly. Sea ice cover has decreased substantially since the 1950s, and surface water temperatures have increased by 0.23°C per decade over the same time period5. We considered the potential effects of climate change on invasion risk by generating and comparing current (2003-2012) and mid-century (2030-2039) habitat suitability models.
Over the next twenty years, our models predict that 40 to 60% of the Bering Sea shelf will shift from unsuitable to suitable habitat, with suitable habitat expanding north.
- Barry, S. C., K. R. Hayes, C. L. Hewitt, H. L. Behrens, E. Dragsund, and S. M. Bakke. 2008. Ballast water risk assessment: principles, processes, and methods. ICES Journal of Marine Science 65:121–131. doi: 10.1093/icesjms/fsn004
- Hewitt, C. L., and K. R. Hayes. 2002. Risk assessment of marine biological invasions. Pages 456–466 in E. Leppäkoski, S. Gollasch, and S. Olenin, editors. Invasive Aquatic Species of Europe. Distribution, Impacts and Management. Springer Netherlands, Dordrecht, NL.
- Ruiz, G. M., and C. L. Hewitt. 2009. Latitudinal patterns of biological invasions in marine ecosystems: a polar perspective. Pages 347–358 in I. Krupnik, M. A. Lang, and S. E. Miller, editors. Smithsonian at the Poles: Contributions to International Polar Year Science. Smithsonian Institution Scholarly Press, Washington, DC.
- Hermann, A. J., G. A. Gibson, N. A. Bond, E. N. Curchitser, K. Hedstrom, W. Cheng, M. Wang, E. D. Cokelet, P. J. Stabeno, and K. Aydin. 2016. Projected future biophysical states of the Bering Sea. Deep-Sea Research Part II: Topical Studies in Oceanography 134:30–47. doi: 10.1016/j.dsr2.2015.11.001
- Mueter, F. J., and M. A. Litzow. 2008. Sea ice retreat alters the biogeography of the Bering Sea continental shelf. Ecological Applications 18:309–320. doi: 10.1890/07-0564.1