Monster Seminar JAM - Transport of toxic dinoflagellates via ships ballast water: Bioeconomic risk assessment and efficacy of possible ballast water management strategies
Dr. Gustaaf M. Hallegraeff, University of Tasmania, Centre for Marine Science
Professor Gustaaf Hallegraeff was born in the Netherlands and educated at the University of Amsterdam, before migrating to Australia to join the CSIRO Marine Laboratories and later the School of Plant Science of the University of Tasmania. He is recognised nationally and internationally for his marine biosecurity work on harmful algal blooms impacting on human health, the fish farm and shellfish industries, their stimulation by coastal eutrophication and global spreading via ship's ballast water. He was awarded the 2004 Eureka Prize for Environmental Research and elected a Fellow of the Australian Academy for Technological Sciences and Engineering in 2005.
The potential for transport of nonindigenous marine microalgae via ships' ballast water has been amply demonstrated. A plausible scenario for successful introduction and establishment of toxic dinoflagellates such as Alexandrium tamarense, Gymnodinium catenatum is: (1) ballast water intake during seasonal plankton blooms and to a lesser extent via resuspended cysts in port sediments; (2) survival as resistant resting cysts during the ballasting process, the voyage in a dark ballast tank, and subsequent ballast water discharge (inoculation); (3) successful germination of cysts, sustained growth and reproduction of plankton cells in port; and (4) further spreading via coastal currents or domestic shipping, culminating under suitable environmental conditions in harmful algal blooms impacting on human health and aquaculture (causative organisms of Paralytic Shellfish Poisoning). Molecular approaches are increasingly suggesting that global microalgal diversity and therefore human-mediated translocations have been seriously underestimated. Genetic exchange between resident and invader strains is also of concern. With the adoption of the International Convention for the Control and Management of ships Ballast Water and Sediments a consensus has now been reached that not doing anything is no longer an option. Minimizing the risk of ballast water introductions by microalgae and their cysts represents a very significant scientific and technological challenge, which cannot yet be adequately achieved with best currently available technologies. Whereas ballast water exchange can be effectively utilised on transoceanic voyages, it has proved less successful for continental shelf voyages due to the lack of suitable ballast water exchange locations. Examples of promising higher standard treatment technologies include heating, mechanical removal of organisms in combination with UV treatment, as well as chemical biocide treatment of ballast water. In addition to ship ballast water translocations, climate change driven species range expansions are increasingly adding to the unpredictability of algal biotoxin problems thus calling for increased vigilance in seafood biotoxin and HAB monitoring programmes.
Date and Time:
April 9, 2009,
11:00 am - 12:00 pm