Sinlapachai Senarat, Wannee Jiraungkoorskul, and Jes Kettratad

DOI: 10.14456/sjst-psu.2017.26

pp. 225 - 235

Abstract

The ovarian structure and reproductive health of short mackerel, Rastrelliger brachysoma in the upper Gulf of
Thailand from non-breeding (October to November 2013) and breeding seasons (December 2013 to February 2014), were
examined by histological and histochemical techniques. The results revealed that the ovary in this species was enclosed by
the tunica albuginea. It was considered as an asynchronous type, which could be classified into seven stages based on its
histological characteristics. These seven stages were oogonium, chromatin nucleolar, perinucleolar, oil droplet and cortical
alveolar, early, late and post vitellogenic stages. During the oogenic processes, the change and characterization of inclusions
including lipids, cortical alveoli and yolk granules were detected by histolochemical techniques. The ovarian histopathology
in R brachysoma was detected. This includes ovarian degeneration, ovarian atrophy and atresia in different stages (oogonia,
previtellogenic stages and vitellogenic stages) as well as melano-magcrophage centers. Atretic follicles and ovarian atrophy
were also observed and could negatively affect the reproductive health of the species, which could lead to population
declines in R. brachysoma as well as threaten other marine fishes connected through the food web in Thailand.