Fig. 1. Publicly unidentified and potentially unauthorized fishing.

(A) For the top 30 flag states (in ISO-3166 country code, China being the first) during 2012–2021, number of fishing and support vessel identities estimated to be larger than 24 meters. Color codes correspond to (i) vessels identities matched between registries and AIS (blue), (ii) vessels identities present in AIS data but unmatched to registries (red), and (iii) vessels identities recorded in registries but unmatched to AIS data (yellow). These unmatched registry records (yellow) largely represent vessels unequipped with AIS devices but may also be due to discrepancies between identity fields in AIS and registries. See Fig. 3 for ISO-3166 country codes. (B) Fishing effort by vessels whose identity can be correlated to registry records. (C) Fishing on the high seas by vessels with known versus unknown authorization.