Research ProjectOcean Corridors

Ocean Corridors and the Spread of Invasive Species: Consequences of Socioeconomic and Climatic Factors

Project Goal

This global-scale project assesses the transfer risks of nonnative marine species associated with commercial ships sailing between oceans. Specifically the risks associated with expanding inter-ocean trade corridors such as the widening of the Panama and Suez Canals, the dredging of Malacca Strait and the seasonal opening of the Northwest Passage.


Although interocean shipping is not a new phenomenon, shifting trade patterns provide new opportunities for dispersal of nonnative marine species that hitch rides inside ballast tanks or stick to hull surfaces of ships. Our team assesses the implications for biological invasions resulting from changes in maritime transportation corridors, which are growing in magnitude or moving geographically due to various socioeconomic and climatic factors. For instance, the Panama Canal expansion will likely boost U.S. sea trade with China and other Asian markets, which will increase the interchange of shipborne species between these countries. Trends in extraction of energy and mining products from the seabed alter commercial vessel behavior and sea ice loss in the Arctic are opening new high-latitude shipping routes, which favor exchange of temperate and cold-water species. 

In the laboratory, we test experimentally whether new invasions are possible for organisms hitchhiking on ship hulls during transit of these emergent inter-ocean corridors. Our state-of-the-art “voyage simulator” allows us to expose biofouling species* to the fluctuating temperature and salinity conditions experienced by organisms attached to the hull surface of a vessel en route. We can then answer: “Which species will survive an ocean crossing attached to the outside of a ship? Will any have the energy reserves to reproduce at the next port?” The answers to these questions have broad applications for invasion ecology, global biogeography and international maritime biosecurity regulations.


Holzer, Kimberly K., Jim R. Muirhead, Mark S. Minton, Katharine J. Carney, A. Whitman Miller, Gregory M. Ruiz. 2016. Potential effects of LNG trade shift on transfer of ballast water and biota by ships. Science of The Total Environment. Online December 2016, 


Kimberly Holzer

Term Definition
Biofouling species Organisms like barnacles, mussels, sponges, algae and sea squirts attach themselves to the hulls of ships, fouling them. These organisms then colonize the hull and "hitch a ride" from one port to the next. Invasions can occur when these fouling organisms release their larvae into its waters adjacent to structures in a new port. Under the right conditions, these invaders may establish themselves in the new port and spread to nearby areas within that region.