Unfortunately, data analysis is only as good as the data. Wired reports: Last week, Google, Oceana and SkyTruth announced they were launching a battle against overfishing everywhere. A noble pursuit, Global Fishing Watch combines interactive mapping technology and satellite data with the all-important Automatic Identification System (AIS) transmissions every tanker, passenger ship and commercial vessel above a certain size is mandated by the UN to send. Global Fishing Watch then visualises the routes taken, to show when a fishing boat strays into or lingers in waters it shouldn’t.

The only problem, maritime analytics company Windward tells us, is that any vessel engaging in illegal activities is gaming the system and manipulating AIS data. We can’t rely on what we’re seeing.

“Until 2012, AIS data was super reliable because it wasn’t commoditised. Nobody had it, so no one needed to clean the data or check it,” Ami Daniel, a former naval officer and cofounder of Windward, tells WIRED.co.uk. “Two years, there was suddenly so much data out there, so many open source portals like marinetraffic.com providing free access to [vessel positions] for everybody. People understood they were being looked at. Once that happened, spontaneously different industries started to manipulate the data.”

According to a report by Windward that looked at AIS data from mid-2013 to mid-2014, there has been a 59 percent increase in GPS manipulations. From July 2012 to August 2014, that data also showed: [Continue reading…]