Revealing the Global Longline Fleet with Satellite Radar

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Authors

David Allen Kroodsma , Tim Hochberg, Pete Davis, Fernando Paolo, Rocio Joo, Brian Adrian Wong

Abstract

Because many vessels use the Automatic Identification System (AIS) to broadcast GPS positions, recent advances in satellite technology have enabled us to map global fishing activity. Understanding of human activity at sea, however, is limited because an unknown number of vessels do not broadcast AIS. Those vessels can be detected by satellite-based Synthetic Aperture Radar (SAR) imagery, but this technology has not yet been deployed at scale to estimate the size of fleets in the open ocean. Here we combine SAR and AIS for large-scale open ocean monitoring, revealing that, between September 2019 and January 2020, non-broadcasting vessels accounted for about 35% of the longline activity north of Madagascar and 10% of activity near French Polynesia and Kiribati’s Line Islands. We further demonstrate that this method could monitor half of the global longline activity with about 70 SAR images per week, allowing us to track human activity across the oceans.

DOI

https://doi.org/10.31223/X5M34J

Subjects

Aquaculture and Fisheries Life Sciences, Remote Sensing

Keywords

SAR, Longlines, synthetic aperture radar, Fishing, AIS, remote sensing, Fisheries

Dates

Published: 2022-04-06 07:56

Last Updated: 2022-04-06 14:56

License

CC BY Attribution 4.0 International

Additional Metadata

Conflict of interest statement:
None

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