New technologies prevent aquatic species invasions
Recently, researchers from the University of Notre Dame’s Environmental Change Initiative (ECI) applied new techniques to help detect and prevent aquatic invasive species from entering US waters (Conserv Lett 2013; doi:10.1111/ conl.12017). Once established, such species cause massive ecological and economic damage to fisheries and other industries each year. “This research combines two emerging but proven technologies – environmental DNA (eDNA) and Light Transmission Spectroscopy (LTS) – to address the growing problem of aquatic invasive species by increasing our ability to detect dangerous species before they arrive or when they are still rare in the environment and have not yet caused substantial damage”, says lead author Scott Egan (ECI, Notre Dame, IN). These new methods will improve the monitoring of ships’ ballast waters, which often harbor stowaway organisms. In the Great Lakes alone, approximately 180 non-indigenous species have become established since European settlement, with about 70% arriving in water discharged from the ballast tanks of transoceanic ships.
eDNA is a species surveillance tool that examines DNA found in microscopic bits of tissue of various aquatic species (eg pieces of fish scales and insect exoskeletons) suspended in the water. LTS can detect changes in the size of small particles as they come into contact with the DNA of specific target species, even if those species are relatively scarce in the water samples. Given the importance of ballast-water monitoring, this work “implies that eDNA sampling and LTS could enable rapid species detection in the field in the context of research, voluntary or regulatory surveillance, and management actions to lower the risk of the introduction or spread of harmful species”, attests Egan.
For the future, Egan and his ECI colleagues are working to improve the sensitivity of LTS for even lower concentrations of target species and to expand the number of species these techniques are able to detect. They are also developing a species detection platform that uses all of these tools in the field, on large ships or at points of entry to the US. As Egan explains, “Future research applications will expand analyses to include threatened or endangered species, pest species of agricultural concern, infectious species of health concern (eg pathogens and parasites), and species that pose biosecurity risks”.