In the present research, the Catch-only method was used to determine the biological reference points (BRPs) of Longtail tuna (LOT) in Iranian southern waters (Persian Gulf and Oman Sea). Depletion-based stock reduction analysis (DBSRA) and Catch maximum sustainable yield (CMSY) models were used to estimate BRPs by applying data from 1997 to 2018.The B/BMSY
was calculated as smaller than 1.0 in both models, while F/FMSY
was mostly higher than 1.0, which indicates the overfishing of Longtail tuna in this area. In 2012, the F/FMSY
ratio has exceeded over 1.01 and the B/BMSY
ratio with 2 years delay was declined in 2014. Consequently, the biomass reduction followed in 2016, declined to the below of BMSY
and the fishing pressure was not adjusted to combat. In comparison, DBSRA model indicated more cautious than CMSY in BRPs estimation for LOT in Iranian southern waters. Based on BRPs, it is recommended to implement an adjustment of annual harvest (around 55 thousand tons) as the simple (even quick) ﬁsheries management strategies in order to guarantee the sustainable yield of this species in southern waters of Iran. We also recommend that catch-only methods could be treated as a temporary stepping-stone
while sufficient data
(e.g. size or age composition) is available for more reliable methods to be applied.