Reconstructing past fisheries catches for large pelagic species in the Indian Ocean

Comprehensive catch data are fundamental to support the sustainable management of large pelagic fisheries. However, reported by Indian Ocean Tuna Commission (IOTC) on behalf its member countries currently under-represent extent these fisheries in Ocean. We reconstructed catches species for from 1950 2020, aiming improve comprehensiveness existing and provide more ecologically relevant datasets research uses. 42 operating five major gear groups (longline, purse seine, gillnet, pole-and-line, other gears) Reconstructed were 30% higher than IOTC. demonstrated that distant-water fishing fleets historically dominated large-scale industrial but gradually replaced flagged rim countries. Our results also indicated an average discard rate ~14% over 1950-2020 period, primarily attributable extensive discarding practices associated with longline gillnet vessels. Reporting time has improved only tunas, whereas shark still remain under-reported, accounting 51% total unreported landings discards 2020. confirmed substantial taxonomic aggregation IOTC countries, masking important patterns trends further complicating exploited recommend substantially increased observer coverage far better stronger all statistics