Otoliths, crucial tools for understanding fish biology and ecology, offer valuable insights into fisheries science in Southeast Asia. Traditionally used for age identification through shape analysis and growth ring counting, otolith studies have evolved to encompass broader ecological investigations. This review synthesizes literature on fish otoliths in Southeast Asia to identify research gaps and suggest future directions. Utilizing targeted keywords, we mined data from scientific search engines, focusing on peer-reviewed articles. Our analysis spans 1988 to 2021 and collated 129 publications, which were trimmed to 91 reviewed scientific articles. Otolith microstructure emerged as a primary research area of interest, with a focus on catadromous fishes from the Anguillidae family.

Organogenetic alterations described over the stages of gonadogenesis at the gross and microscopic scale can be used to determine spawning behavior in iteroparous fishes and provide finer details of the reproductive functions of commercially important species. This information can be used as the basis for stock assessment and maintenance of wild populations. In this study, the gross morphology of Eastern Little Tuna (Euthynnus affinis) gonads from Sarangani Bay, Davao Gulf, Moro Gulf, and Sulawesi Sea collected in 2020–2022 was investigated along with its microanatomy through histotechniques.

Structural and functional maturation in gametogenesis through comprehensive histoarchitectural and gross morphological analyses can serve as a powerful tool for gauging population health and resilience within gonochoristic fish populations. The Philippines boasts a robust neritic tuna fishery, with Bullet Tuna (Auxis rochei) being a significant species. Nonetheless, our understanding of reproductive parameters in neritic tunas remains deficient, hampering sustainable management strategies. In this study, 975 fish samples were collected from Sarangani Bay, Davao Gulf, Moro Gulf, and Sulawesi Sea.

T he structural configuration of oogonial and spermatogonial models in oviparous species are key determinants of reproductive biological parameters, as these factors also determine gonadogenesis and spawning lengths. This study systematically characterized frigate tuna (Auxis thazard) collected from the southern Philippine waters, including Sarangani Bay, Davao Gulf, Moro Gulf, and the Sulawesi Sea. Characterization involved a comprehensive analysis of gross gonadal features, aided by gross morphological identification and histological profiling utilizing Hematoxylin and Eosin (H&E) staining.