Each visit counts with the share of its fleet (gear and flag) that the forced-labor model rated high risk.
Each port visit counts with the share of its fleet (gear and flag) that the model rated high risk in 2018. A visit by a fleet with 75% high-risk vessels counts as 0.75. The map shows fleets, not individual vessels, and says nothing about any specific vessel or port.
Fleet risk comes from the model's 2018 predictions and is applied to 2024 visits. The vessels are the squid jiggers and longliners in the model's 2018 data, so vessels that started fishing later are missing, and fleets that grew since then are undercounted. A large circle means that many visits came from fleets the model rated high risk. It is not a finding about any port or any vessel.
Sources: fleet risk and vessel list from McDonald et al. (2021), PNAS, published data; port visits from Global Fishing Watch.