Updated Reproductive Biology of Skipjack Tuna in Northeastern Indian Ocean

Skipjack tuna (Katsuwonus pelamis) is a tropical tuna species and has been historically exploited in the south and western parts of Indonesia waters. The objective of this study was to determine the biological reproductive parameters of female skipjack obtained from the Indonesia Fisheries Management Area 572 and 573 (Northeastern Indian Ocean). Samples were collected from the landing site in southern Java and Bali (Cilacap, Kedonganan, and Benoa), and western Sumatra (Lampulo, Sibolga, and Padang). Catches come from various gears such as handline, purse seine, lift net, and longline. Samples were collected during 2018-2021 and a total of 400 ovaries were obtained from fish with the length ranged between 28.3 - 72 cm 19 FL. The size at first maturity (Lm50) of female skipjack in the northeastern Indian Ocean was 38.2 cm FL. The estimated mean batch fecundity was 0.29±0.18 million oocytes (n=11), and the mean relative batch fecundity was 107.11±29.26 oocytes/gr. The peak spawning season of skipjack tuna occurred between September and February, spawning every 1.82 days within the spawning period.