Reprint of “Estimating tag reporting rates for tropical tuna fleets of the Indian Ocean”

Estimates of tag reporting rates are necessary in order to estimate tag-recovery rates and interpret tagging data in terms of movement rates, exploitation rates and abundance. We describe a Bayesian framework for the estimation of reporting rates for multiple fleets using coincidental tagging and catch data disaggregated by fish size, species, location and time. The method was applied to the data of the Indian Ocean Tuna Tagging Programme (2006–2011) and tag seeding experiment of the Indian Ocean Tuna Commission (2004–2009). Reporting rates were estimated for 13 Indian Ocean tuna fleets. These estimates varied widely from 94% for the European Union purse seine fleet to less than 1% for fishing operations of non-longline/non-purse seine fleets in the Eastern Indian Ocean. Generally, reporting rates were high compared with estimates for tuna fisheries in other Oceans.