Estimating the size at sexual maturity of bigeye tuna (Thunnus obesus) in the eastern Indian Ocean

Accurate information of reproductive characteristics of bigeye tuna (Thunnus obesus) is an important factor in determining its regeneration capacity in a population. However, a robust analysis with proper samples representation in the eastern Indian Ocean was still limited. The study aimed to give a preliminary result on estimating size at maturity of bigeye tuna based on histological datasets from 2019-2020. A total of 78 female bigeye tuna (78-161 cm FL) were sampled from Indonesian longline fisheries and the ovaries were analyzed histologically. The estimated length at maturity (Lm50) was 101.25 cm FL at the advanced yolked stage as the threshold of maturity.