Abstract
A methodology had been proposed for cross-matching visible infrared imaging radiometer suite (VIIRS) boat detections (VBD) with vessel monitoring system (VMS) tracks. The process involves predicting the probable location of VMS vessels at the time of each VIIRS data collection with an orbital model. Thirty-two months of Indonesian VMS data was segmented into fishing and transit activity types and then cross-matched with the VBD record. If a VBD record is found within 700 m and 5 s of the predicted location, it is marked as a match. The cross-matching indicates that 96% of the matches occur while the vessel is fishing. Small pelagic purse seiners account for 27% of the matches. Other gear types with high match rates include hand line tuna, squid dip net, squid jigging, and large pelagic purse seiners. Low match rates were found for gillnet, trawlers, and long line tuna. There is an indication that VMS vessels using submersible lights can be identified based on consistently low average radiances and match rates under 45%. Overall, VBD numbers exceed VMS vessel numbers in Indonesia by a nine to one ratio, indicating that VIIRS detects large numbers of fishing boats under the 30 Gross Tonnage (GT) level set for the VMS requirement. The cross-matching could be used to identify “dark” vessels that lack automatic identification system (AIS) or VMS.
Highlights
The continuing decline in global fish stocks places an increasing importance on fishing vessel surveillance to better understand individual fishing grounds and to provide a basis for enforcement of fishing regulations and counter illegal, unreported, and unregulated (IUU) fishing activities
While formal implementation of vessel monitoring systems (VMS) attached on board of fishing vessel and fish carrier vessel for 30 gross tonnage (GT) or larger has been formalized by the Ministry Regulation number 42 in 2015, which represent approximately 10% of the domestic fishing fleet [1]
Our study has four objectives: (1) to identify the gear types that are commonly detected by visible infrared imaging radiometer suite (VIIRS) in Indonesia, (2) to rate the probability that a boat is fishing if it is detected by VIIRS, (3) to determine the probable gear type for a VIIRS boat detections (VBD) in Indonesia fishery management zones (WPP), and (4) to determine if different styles of lighting can be discerned
Summary
The continuing decline in global fish stocks places an increasing importance on fishing vessel surveillance to better understand individual fishing grounds and to provide a basis for enforcement of fishing regulations and counter illegal, unreported, and unregulated (IUU) fishing activities. Log books recording date ranges, locations, and catch weights are required in certain jurisdictions These records are typically not submitted until after the vessel returns to its landing site and there is no centralized system for sharing these records. Individual fishing boats can be tracked in near real time using vessel tracks from automatic identification system (AIS) and vessel monitoring systems (VMS). These systems provide an incomplete view of fishing boat activity and the data are generally restricted in terms of access. There is substantial interest in identifying “dark vessels” that lack an accurate AIS or VMS signal This is a tip-off of possible illegal fishing in certain fishing grounds. The only way to identify “dark vessels” is to combine AIS and VMS with complimentary vessels detection sources
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