The first large-scale study of transshipment events suggests that many exchanges of goods at sea occur beyond the jurisdiction of any one nation. In the absence of consistent regulation, illegally-caught fish are entering supply chains and other criminal activities, such as drug smuggling, are facilitated.
"The practice of transshipment – refrigerated cargo vessels meeting with fishing boats at sea to exchange seafood, crew, fuel or supplies – is common in many fisheries as it enables fishing vessels to remain at sea while their catch is taken to market," explains the study’s leader, Dr Nathan Miller of nonprofit environmental watchdog SkyTruth. "However, it lacks uniform regulation and transparent data. This hinders sustainable fisheries management as it makes it very difficult to monitor the amount of marine life being taken from the sea."
The team of researchers from Google, SkyTruth and Global Fishing Watch analyzed more than 30 billion vessel tracking signals to identify potential transshipment events. This included refrigerated cargo vessels loitering at sea long enough to receive a transshipment, or two vessels in close proximity for enough time to transfer catch, crew or supplies.
Transshipment activity was observed in all ocean basins, but was most common in international waters. Almost half of the exchanges tracked by the researchers took place on the high seas and involved vessels registered in countries that likely differ from the vessel’s owner. “This means that vessel may be held to less strict standards and regulations than its home country would require,” Miller explains.
Use of the vessel tracking system that the study’s data is derived from varies widely between fleets. Ship operators can also choose to turn off the tracking device or broadcast incorrect identity information. Areas of the ocean with high concentrations of vessels and shipping activity can also harm the accuracy of tracking data. However, Miller says that the results don’t change much if these parameters are accounted for.
"We hope our results will expose the potential association of transshipment with illegal fishing and other criminal activities, as well as stimulate discussion on sustainability and management of high seas fishing," he says. "Tackling the sustainability and human rights problems associated with transshipment at sea will require global perspective and cooperation."