Heeding the Lionfish Warning

Scientists from NOAA and other research bodies believe that it is very unlikely that ballast water or hull-fouling caused the invasion of the Indo-Pacific lionfish into East Coast U.S. waters. It was more likely the result of releases from aquaria hobbyists. Still, there are lessons to be learned from their Western Atlantic invasion, lessons that could be applied to Australia’s Great Barrier Reef (GBR).

The GBR has been the center of controversy regarding the decision about whether or not the coal terminal at Abbot Point should be expanded, and if so, where the dredging material should be dumped. The Australian government detailed in March how it will ban dumping of all dredge soil in the Great Barrier Reef as it looks to step up protection of the world’s largest reef and avoid having it listed by UNESCO as “in danger.”

UNESCO’s World Heritage Committee is due to decide in June whether to put the GBR on its “in danger” list because there have been substantial declines in healthy coral cover and some of its high-value species, including dugongs and large green turtles, are threatened.  Such a listing could lead to restrictions on shipping and port expansions that could hit Australia’s trade.

So far much of the controversy has focused on the effects of dredging, but a study published last week by the Royal Society from researchers at the University of Adelaide, Australia, says ballast water is a growing risk to the reef. The Adelaide study identified that the amount of ballast water dumped in Australia’s ports has more than doubled between 1999 and 2012 with the vast majority of these discharges and associated bio-invasion risk linked to the bulk export trade.

“As such, the ecoregions suffering the greatest risk are those associated with the export of mining commodities,” say the researchers, who cited much of the Queensland coast and adjoining GBR as one of these areas.

The connection with lionfish comes from another study published last week, in which scientists from Brazil, the U.S. and Australia confirmed that the first recorded sighting and capture of lionfish in Brazilian waters was an individual genetically linked to those which have invaded much of the Caribbean as well as the Gulf of Mexico and U.S. eastern seaboard. The fish were found on a subtropical reef at Arrail do Cabo, which implies the Brazilian invasion has been underway for some time as this cape is over 5,000 km to the south and not far from Rio de Janeiro.

It is unlikely the result of ballast water transfers as there is no substantial port in the vicinity and more likely due to the continuing natural range expansion of a species that has proven well adapted to spread rapidly across much of the western Atlantic.

The authors of the study recommend urgent control, management and education measures aimed at minimizing the effects of the impending invasion. They’ll probably be disappointed.  

According to NOAA, most scientists agree it is unlikely that the lionfish’s Atlantic invasion can be reversed. Any large-scale attempts to remove the existing lionfish presently appear impractical and would be very costly because of the large geographic range and depths that this fish has already attained. Lionfish are now found along the entire southeast U.S. coastline at depths between one and 1,000 feet, making their complete removal all but impossible.

Indo-Pacific lionfishes now join the ranks of other harmful aquatic invasive species that have taken up permanent residence on America’s eastern seaboards, including Caspian zebra mussels and European green crabs.

Australia’s GBR already has its own lionfish but with the expansion of shipping in the region, the potential for invasive species is likely to increase, particularly from East Asia.

Australia was one of six initial signatory nations to IMO’s ballast water management convention, rushing its deposit in May 2005 just ahead of the 12-month closing date. But the country has still not ratified this convention as the relevant national regulations are yet to be put in place under a new Biosecurity Act that has taken years to develop.

There’s been no exterior pressure to ratify as Australia’s tiny amount of nationally flagged tonnage will have negligible effect on moving the entry-into-force tonnage toward the required 35 percent of global total.  

Australia continues, however, to exert strict requirements for ballast water exchange and, as with New Zealand, California and other states, has been examining ways to reduce the biofouling threat. But until the ballast water management convention enters into force and fouling management of hull niches is given more global attention, the imperfect procedure of ballast exchange provides Australia’s only defense to preventing what the lionfish represents: an irreversible invasion event that can spread vast distances to threaten ecosystems within and beyond the GBR. - MarEx