Preliminary evaluation of IOTC Form 3DA implementation and proposed improved dataflow

This paper presents an initial assessment of Form 3DA submissions under the IOTC Drifting Fish Aggregating Device (DFAD) reporting framework. The analysis focuses on reporting coverage, data completeness, internal consistency, and the extent to which submitted information can support the monitoring and management of DFAD activities in the Indian Ocean purse seine fishery. Rather than providing a general overview of the fishery itself, the paper evaluates the reporting system as an operational monitoring tool: what was submitted, how usable the data are, what patterns can already be described, and what practical improvements could strengthen future reporting.

The assessment covered submissions from eight CPCs, representing 44 purse seine vessels and 10 supply vessels, comprising 86,261 reported records. Reported activities included 8,797 fishing events, of which 8,147 contained associated catch information. Reported catches were dominated by skipjack tuna (Katsuwonus pelamis), yellowfin tuna (Thunnus albacares), and bigeye tuna (Thunnus obesus), with additional reporting of associated and dependent species.

Initial assessment indicates that Form 3DA already provides a substantial volume of operational information with clear potential to support DFAD monitoring and management. However, recurring reporting issues were identified, including missing mandatory information, invalid controlled vocabulary entries, and incorrectly formatted fields, which reduced analytical usability and limited interpretation in some areas.

The findings suggest that relatively practical improvements could substantially increase the value of future submissions, including clearer reporting guidance, refinement of controlled vocabularies and field definitions, automated pre-submission validation, and targeted adjustments to the reporting form to reduce ambiguity and improve analytical usability.

Revised version of document IOTC-2026-WGFAD08-08-DFAD_data_reporting posted on 25/05/2026

Revised version of document IOTC-2026-WGFAD08-08-DFAD_data_reporting posted on 02/06/2026 One more CPC included in data, as long/lat data was provided.

Revised version of document IOTC-2026-WGFAD08-08-DFAD_data_reporting posted on 09/06/2026 Included table breaking down NA in activities on FADs as requested.