Content of the dataset:
Estimates of annual catches in live weight equivalent (metric tonnes) of the five major IOTC species (ALB, BET, SKJ, SWO, and YFT) by year, fleet, gear, type of fishery (artisanal / industrial), and area of capture (coastal state EEZ / high seas), covering the years from 1950 to 2021 included.
How original data have been processed to produce these estimations:
- By using the IOTC best-scientific estimates of nominal catches and the officially reported geo-referenced catch-and-effort and size-frequency data (see: https://www.iotc.org/data/datasets)
- By removing all catches from NEI fleets, such as NEIFR (deep-freezing tuna longliners NEI), NEICE (fresh tuna longliners NEI), NEIDN (NEI fleets operating in IDN EEZ), NEISU (ex-Soviet Union) and NEIPS (purse seine fleets NEI)
- By determining the artisanal / industrial status of a fishery on the basis of the specific fleet + gear combination (as available in the IOTC database)
- By estimating the spatial allocation (over regular 5x5 grids) of catches from those fleets / fisheries that did not report or reported incomplete geospatial data, through proxy records that might refer to multiple years and fleets / fisheries
- By estimating the weight of geo-referenced catches that are originally available in numbers only (e.g., longline fleets) using size-frequency data from the same fleet or from proxy fleets / years
- By raising the fully geo-referenced catch estimates to the total annual catches (in weight) by fleet, gear, and species
- By attributing artisanal catches to the EEZ of the corresponding flag state
- By using the EEZ definitions as these currently appear within the IOTC database (geospatial data provided upon request as standard shapefiles and as a table containing the proportion of overlapping area calculated for 1x1 / 5x5 regular grids and EEZs / High Seas) and considering:
- The so-called "BIOT" / Chagos EEZ as the EEZ for the GBR / GBRT flag state / CPC
- The so-called "France (territories)" EEZ as the EEZ for the FRAT flag state / CPC, including Mayotte EEZ from 1950 to 2013 and excluding Mayotte EEZ from 2014 onwards
- The EEZ of Réunion (from 1950 to 2016) and Mayotte (from 2014 onwards) as the EEZ for the EUR flag state / CPC
- No specific sovereignty on the disputed areas between Kenya and Somalia and Somalia and Yemen, and that - for this reason - catches in these two areas have been considered as High-Seas catches
- By attributing catches in a grid that overlaps multiple EEZs and / or the high seas to the corresponding area proportionally to its relative size within the grid (see also: https://www.iotc.org/documents/estimation-eez-catches)
References:
Disclaimer:
Due to the assumptions underpinning points 4, 5, 6, and 9 above, the results presented in the Data worksheet cannot be considered as an accurate indication of the effective area of operation of all fleets concerned.
Therefore, this information shall not be considered as equivalent to official IOTC geo-referenced catch data, nor can be referred to as such, and its applicability is limited to TCAC purposes only.
The designations employed and the presentation of data and material in this information product do not imply the expression of any opinion whatsoever on the part of the Food and Agriculture Organization of the United Nations (FAO) and the Indian Ocean Tuna Commission (IOTC) concerning the legal or development status of any country, territory, city or area of its authorities, or concerning the delimitation of its frontiers or boundaries.
