Bright Lights Reveal the “Dark” Fleet
A new partnership between Global Fishing Watch and NOAA matches
night-time imagery with monitoring data from fishing vessels.
January 16, 2018: Global Fishing Watch has entered into a new data-sharing partnership with the U.S. National Oceanic and Atmospheric Administration (NOAA) to improve understanding of the activity of fishing vessels in Indonesian waters. Through the partnership, Global Fishing Watch and NOAA are matching Vessel Monitoring System (VMS) data from the Indonesian government with NOAA’s satellite based Visible Infrared Imaging Radiometer Suite (VIIRS), which reveals the locations of brightly lit vessels at night. The idea is to identify fishing vessels that are not picked up by other monitoring systems and to test and refine the use of VIIRS for identifying and distinguishing different types of fishing vessels.
By cross matching VMS from Indonesia with VIIRS, the team found that roughly 80 percent of VIIRS detections could not be correlated to a vessel broadcasting VMS. The vast majority of these vessels are likely to be fishing vessels using bright lights to attract fish. While a small number may be other types of vessels, most ships do not use lights bright enough for detection. This work indicates that the addition of VIIRS data can greatly enhance transparency in commercial fishing in Indonesia.
The team believes most of the VIIRS detections are from fishing vessels not required to carry VMS because they are under the 30 gross ton (GT) threshold established by the government of Indonesia. It is also possible that some vessels detected only by VIIRS meet the size requirement but have switched off their VMS or have a faulty device. Another possibility is that VIIRS is detecting foreign boats that are not carrying VMS because they are poaching from Indonesian waters.
“I’m excited for this opportunity to see the dark fleet,” said David Kroodsma, Global Fishing Watch Research Program Director. The dark fleet being a common term used to describe vessels that don’t show up in vessel monitoring systems and therefore are said to operate in the dark. “NOAA’s VIIRS data shows us vessels we can’t see by any other means and helps us to gain a more complete picture of fishing activity.”
Global Fishing Watch detects nearly all large fishing vessels in Indonesian waters by combining Indonesia’s VMS data and publicly broadcast AIS data which is required on vessels exceeding 300 GT. Global Fishing Watch can even tell when vessels turn off their monitoring devices. But the system is unable to see vessels when they are not broadcasting either AIS or VMS. Incorporating VIIRS, which represents a completely new source of data, into the Global Fishing Watch database and, eventually, the public mapping platform, will reveal the activity of even more of the world’s commercial fishing fleet.
To cross match VMS and VIIRS, NOAA’s Earth Observation Group developed an orbital model that predicts the probable location of each VMS-broadcasting vessel at the time of the VIIRS data collection. The model checks the predicted location against the actual VIIRS detections to define matches. Prior to the partnership with Global Fishing Watch, NOAA had access to two months of Indonesia VMS data, which they used to develop their cross-matching algorithm.
The partnership with Global Fishing Watch has provided three years-worth of Indonesian VMS data, which NOAA has now matched to its VIIRS vessel detections. In addition, the partnership has provided NOAA with valuable information on vessel gear types and identification numbers in the VMS records.
This new data is enabling NOAA to calculate the frequency of VIIRS boat detections for the different fishing gear types and to work towards a calibration for estimating wattage from the VIIRS detected radiance. “When I saw what Global Fishing Watch could provide in the data, I said, Wow, that could really help us a lot, because we don’t have access to this information in any other way,” said Chris Elvidge, NOAA’s Earth Observation Group Lead. His team is creating an atlas of fishing grounds for Indonesia using the three years of VMS provided by Global Fishing Watch and multiple years of VIIRS data.
Global Fishing Watch is able to provide the VMS data because of its partnership with Indonesia, which began publicly sharing their VMS through the Global Fishing Watch platform in June 2017. They are the first nation to take such bold steps toward transparency, and Peru has recently signed an MOU to do the same.
Now that Global Fishing Watch has access to the VIIRS boat detection data they can vastly expand the number of fishing boat records reported in the public database. In addition, it would be possible to cross match VMS or AIS data with VIIRS boat detections to identify “dark vessels” which may be fishing illegally. The combined data sources could also be analyzed to detect clusters of fishing boats straddling international boundaries, or fishing in Marine Protected Areas.
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