Researchers from James Cook University and Macquarie University are calling for a rethink of global shipping routes, to prevent whales and sharks from becoming marine ‘roadkill’.
JCU’s Distinguished Professor Bill Laurance said more than 10 billion metric tons of goods travel by sea each year.
“The growth of the shipping trade and the rebound of some whale populations post-whaling is leading to increasing collisions between cargo ships and marine giants. In many ways it’s similar to the problem of wildlife roadkill on land, which claims billions of animals every year,” he said.
Prof. Laurance said marine megafauna such as Great Whales, whale sharks and basking sharks are particularly vulnerable to ships because of their size, migration routes and the whales’ need to travel close to the surface for air.
Prof Laurance is the co-author of a recent paper on the subject, along with Dr Alana Grech, Assistant Director of the ARC Centre of Excellence for Coral Reef Studies at JCU, and whale researcher Dr Vanessa Pirotta from Macquarie University’s Department of Biological Sciences.
Prof. Laurance said deadly ship strikes are not the only threat to the animals.
“There is also the problem of the vessel noise disrupting whales’ delicate communication, and chemical pollution and heavily used routes cutting across and fragmenting habitats,” he said.
Dr Pirotta said lessons from the wildlife impacts of roads could be applied to the ocean, to prevent marine giants becoming ‘roadkill’.
“New shipping routes through whale habitats put vulnerable species at risk, and this study provides a new understanding of how to mitigate shipping traffic,” Dr Pirotta said.
The report’s authors propose limiting the creation of new shipping routes in areas such as the Arctic and broadening shipping exclusion zones to take into account the impact of ships beyond the marine ‘roads’ themselves, such as with noise pollution and chemical contamination.
Designing cleaner and quieter ships would reduce the risk of oil spills and chemical pollution and reduce underwater noise. In addition, implementing speed limits and detours around whale habitats at certain times of year would lessen some of the negative consequences.
“New technologies can accurately monitor whale populations and behaviour, and if combined with data about shipping routes and intensity, could provide a clearer picture of their interaction,” said Dr Pirotta.
“Looking at the impacts of roads on wildlife populations can then help predict what might happen if the shipping industry continues to expand, and this can inform better management plans to protect our marine giants,” she said.
“We can’t let the seas become a killing ground like what’s happening on land,” said Prof Laurance.
Link to paper here.