Geo-referenced catch and effort data - All fisheries

This dataset corresponds to the geo-referenced catch and effort (CE) data for the three tropical tuna species – bigeye tuna (Thunnus obesus), skipjack tuna (Katsuwonus pelamis), and yellowfin tuna (Thunnus albacares) – available for all fishery categories (longline, surface, and coastal) reported to the Secretariat. Catches (in tonnes and/or numbers of individuals) are recorded by fishing fleet, year, gear, type of school, time interval (usually monthly), spatial stratum (typically CWP grid squares of 1°×1° for surface fisheries and 5°×5° for longline fisheries), and species. Effort data are recorded by fishing fleet, year, gear, type of school, time interval, and spatial stratum, but are not stratified by species.

Not all fisheries have reported catches, and therefore geo-referenced data are not available for all retained catch strata. In some cases, the geo-referenced catches do not represent the total catches of all species for a given fleet and gear in a specific year, but rather constitute only a sample of the total.

Except for longline fisheries, the IOTC did not prescribe specific units for effort reporting for many years, which may have resulted in variation in the nature of effort data submitted over time. Gear-specific effort units are now recommended in the IOTC reporting guidelines (see section Geo-referenced catches and efforts), in accordance with the provisions of Resolution 15/01 and the recommendation of the 25^th Session of the Scientific Committee. The latter recommends that the number of sets or operations be reported as a mandatory effort variable for longline and surface fisheries, enabling the Secretariat to accurately and independently estimate the coverage of the Regional Observer Scheme (ROS).

The data originate from the IOTC Contracting Parties and Cooperating Non-Contracting Parties (CPCs) as per the IOTC data requirements (Resolution 15/02). They are submitted annually, mostly using IOTC Form 3CE, and curated by the Secretariat for dissemination prior to IOTC Working Parties and other scientific data users.

Global attributes

• Title: Species-specific retained catches and efforts by fleet, fishery, and spatio-temporal stratum, 1952-2024
• Summary: Curated dataset providing detailed information on the catches and efforts of tuna and tuna-like fisheries operating in the Indian Ocean
• Context of development: Management of tuna and tuna-like species under IOTC mandate
• Data origin: Effort and retained catch data collected on land or at sea by national institutions and the fishing industry, with some data having been previously extrapolated to represent the broader fishery
• Lineage: Data submitted by CPCs and consolidated
• Keywords: catch, effort, tuna fisheries
• Type: Tabular files
• Format: CSV
• Size:
  • 394,813 KB for original dataset
  • 12,264 KB for compressed dataset
• Structures:
  • 879,794 rows x 31 columns for catch dataset
  • 667,119 rows x 17 columns for effort dataset
• Geographic description: Fishing areas within the Indian Ocean
• Update frequency: According to data revisions and updates
• Metadata production date: 20 October 2025
• Source: IOTC
• Data curator: IOTC Secretariat
• Contact: [email protected]
• Associated rights: Public-domain data requiring source acknowledgement

Data fields