8 Flag ID
This chapter details the results of our flag analysis.
8.1 About
The following analysis looks into the relationship between a vessel’s AIS-registered flag and its top-visited (home port) country using data from emLab and Global Fishing Watch.
8.2 Datasets
meds_meds_capstone_annual_vessel_flag_country_emissions_v20241121.csv
ssvid: unique vessel IDflag: AIS-registered countrytop_visited_country_iso3: country the vessel visited the most number of times; home portyear: yearemissions_co2_mt: annual CO₂ emissions (MT)
8.3 Packages
- {tidyverse}
- {kableExtra}
8.4 Methods
8.4.1 1. Full Dataset Mismatch
To give a high level sense of just how much of an issue flags of convenience could be, we assessed AIS-registered flag and top-visited country mismatch for the dataset as a whole.
To do this, we created a match column, populated with the following values:
TRUE: matchFALSE: mismatchNA: no value in AIS-flag, cannot determine.
| match | percent |
|---|---|
| FALSE | 21 |
| TRUE | 75 |
| NA | 4 |
8.4.2 2. Full Dataset Emissions
Next, we looked at how much emissions (MT), on aggregate, could be affected by this flagging issue. We summarized emissions by match (TRUE), mismatch (FALSE), and NA for each year and overall.
| Match | Percentage | Total |
|---|---|---|
| FALSE | 71.13 | 6835022045 |
| TRUE | 28.56 | 2784977001 |
| NA | 0.30 | 29475094 |
8.4.3 3. Overestimating Emissions
To quantify overestimation, or emissions attributed to a AIS-flag that visit different top-country, we assessed the fraction of emissions that end up in a different country (mismatch/FALSE) for each flag by year.
Ex. If for the flag of Panama (PAN) 75% of emissions are from vessels that have a different home port country, this could mean that we are overestimating emissions for Panama by upwards of 75% due to flagging issues.
| flag | total_emissions | percent_emissions_leaving_by_flag |
|---|---|---|
| PAN | 1206570122 | 96.9 |
| LBR | 864314868 | 99.9 |
| MHL | 804641557 | 99.9 |
| HKG | 624671969 | 99.0 |
| SGP | 563593064 | 94.9 |
| MLT | 424942851 | 98.8 |
| DEU | 398070016 | 85.6 |
| BHS | 307567222 | 98.9 |
| GRC | 193952596 | 83.2 |
| CYP | 136205494 | 98.7 |
8.4.4 4. Underestimating Emissions
To quantify underestimation, we assessed emissions for each top-visit country that come from a different AIS-flag.
Ex. If for the country of China 25% of emissions are from vessels that have a different AIS-flag, this could mean that we are underestimating emissions for China by upwards of 25% due to flagging issues.
| flag | total_emissions | percent_emissions_coming_by_flag |
|---|---|---|
| CHN | 2873213170 | 75.0 |
| USA | 1263414706 | 79.1 |
| JPN | 576401931 | 55.3 |
| ARE | 319120513 | 97.2 |
| BRA | 331487795 | 91.7 |
| AUS | 329806075 | 83.2 |
| MYS | 232364455 | 87.3 |
| TUR | 246145472 | 68.5 |
| IND | 194510391 | 78.1 |
| KOR | 248005266 | 59.6 |
8.4.5 Visualize
8.4.6 Assumptions
Where top-visited country is NA, it was filled with AIS-flag value (assumes proper registration).
Vessels are assumed to land catch in their top-visited country, and that catch gets reported to the FAO by that country.