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Assessing the status of the Indo-Pacific Sailfish in the Indian Ocean is challenging due to the paucity of data. We explore alternative methods to assess the stock status of IP Sailfish by using length-frequency data to estimate annual Spawning Potential Ratio (SPR). Normalised annual estimates of SPR for two fleets are combined into a single SPR time series, which is assumed to be proportional to biomass, and used as an index of relative abundance. This index is incorporated in the Bayesian State-Space Surplus Production model, JABBA. The results indicate that there has been a 41% decline in SPR since 1970. B/BMSY declined consistently from the early-1980s to the latest estimate in 2019, while F/FMSY gradually increased from 1980, peaking in 2018 at 1.1. The 2019 estimate of B/BMSY was 1.17, while the F/FMSY estimate was 0.98. There is a 53,7% probability that the IP sailfish stock falls within the green quadrant - not overfished nor subject to overfishing. However, the current catches (average of 30,420 t in the last 3 years, 2018-2020) are substantially higher than the 2019 MSY estimate of 25,905 tons. This suggest overfishing is occurring. Catches should be decreased to below 25,000 tons to avoid further declines.
