Reproductive Biology of the Aquarium Marine Fish Abudefduf vaigiensis (Quoy & Gaimard, 1825) from Iligan Bay, Southern Philippines

Abudefduf vaigiensis is one of the top ten aquarium reef fish in the world, but the supply of this ornamental fish species is mainly from the collection of wild populations. This current study investigated some aspects of the reproductive biology of Indo-Pacific sergeant A. vaigiensis (Quoy and Gaimard 1825) from Iligan Bay, Southern Philippines from August 2021 to August 2022. Monthly samples of 35 to 45 individuals per class size with a range of 6.8 to 15.3 cm (TL) were collected to examine the sex ratio, maturity stages and spawning period, gonado-somatic index (GSI), length at first maturity (L50), and the batch fecundity (BF) of the species. The sex ratio showed female dominance (1:1.09) among size classes and across months. The spawning period displayed a peak during the inter-monsoon or warm month (April) and extends up to the beginning of the Southwest monsoon months (June and July). The higher GSI observed during these months clearly reinforced the occurrence of spawning. Histological investigation during this period displayed the existence of hydrated oocytes, tertiary vitellogenic ovaries, and post-ovulatory follicles (POF), which indicate the recent spawning event. Likewise, in males, numerous spermatozoa in the lumen of tubules in the testes were detected as well as the occurrence of remaining spermatozoa in the lumen of lobules in the sperm duct. The length at first sexual maturity of males (9.44 cm TL) was slightly shorter than females (10.32 cm TL). Batch fecundity significantly increased (p-value = 0.00) with body length and weight respectively.