Ship-Riding Invasive Species Mapped
You’d better watch your striped shells, zebra mussels. European scientists have crunched the numbers and created the first model to analyze the routes that invasive marine species take around the globe.
Every year new exotic marine plants and animals show up outside their native regions, often as unwelcome guests on ships. Take the zebra mussel scourge. The result of all those invasions: billions of dollars in damage to farmers, fishermen, tourism and industry — not to mention the environmental havoc that these stowaways can wreak, according to marine researchers.
Conservationists and ship engineers usually have to wait for an invasion and then respond. But engineer Michael Gastner of Bristol University and mathematician Bernd Blasius of University of Oldenberg took a proactive approach. They analyzed data from two years of detailed ship traffic data and biological records to come up with a model that can forecast the likelihood of an bioinvasion at locations around the world.
By running the numbers, the researchers say they can now identify hotspots most at risk for a bioinvasion. Those areas include Singapore, Hong Kong, as well as the Panama and Suez canals, the BBC reported. Factors such as warmer water temperatures and port traffic increased the likelihood. Their research was recently published in the journal Ecology Letters.
The team also found that long trips across thousands of miles aren’t as much of a concern as previously thought because organisms don’t tend to survive the conditions in the ballast water — part of a tank system that provides stability. Since so many survive short distances in the ballast, ports and ship engineers are experimenting with ways to clean them by using filters, chemicals or radiation.
Even with a new powerful forecasting model, I’m not sure the global shipping industry will ever take all the necessary steps to prevent invaders from hitching a ride. For one, the shipping industry is under economic pressure to avoid investing money and extra time at port.
At the very least a scary forecast could give urgency to better solutions and allow port authorities to add more teeth to the rules in the future. Then perhaps the days of freeloading bioinvaders would be numbered.
Photo: A crayfish surrounded by invasive zebra mussels underwater in Ohio. Credit: Brad Stabler.