Keeping Tabs on Secret Stowaways
Authorities must be ever on the alert to prevent the marine equivalent of the next cane toad or rabbit - be it a fish, shellfish, seaweed or tiny algae - that might displace local species, bring in a new disease or destabilise the harbour ecosystem.
Recent surveys suggest that almost one quarter of all marine species in international harbours may not be indigenous and it can be very difficult to sort out natives from non-natives.
But now researchers from UNSW and the University of California, Davis, have revealed the power of new technologies to identify and track the movement of one such creature, the moon jellyfish.
In a recent study they showed that this now widespread jellyfish could not have migrated naturally around the world. Using genetic data and computer simulations of ocean currents and water temperatures, they simulated the movement of the jellyfish and found strong evidence that their world-wide dispersal began after that of European global shipping and trade, almost 500 years ago.
"Up until now our knowledge of natural and human-assisted dispersal of species has been insufficient to confidently track and predict the spread of non-indigenous marine species," says Professor Matthew England from the University of New South Wales.
"Now we have a tool that can include data on currents, geography and the biology of an organism to help separate natural dispersal from that which happens through shipping and trade," he says.
