Abstract:

It is well-known that pollutants affect aquatic ecosystems; however, there is little information on fish reproductive health as an indicator of aquatic pollution. This study reports the oogenesis and ovarian health problems in important fishes from different habitats potentially affected by pollution. Nine fish species caught in 2016 to 2017 were studied: Atherinomorus pinguis (Lacépède, 1803), Alepocephalus bicolor Alcock, 1891 and Neoscopelus microchir Matsubara, 1943 from the mesopelagic habitats; Monacanthus chinensis (Osbeck, 1765) from the coastal habitat; and Nuchequula gerreoides (Bleeker, 1851), Eubleekeria splendens (Cuvier, 1829), Pisodonophis boro (Hamilton, 1822) and Allenbatrachus grunniens (Linnaeus, 1758) from the estuarine habitat. Hippocampus barbouri Jordan & Richardson, 1908 under captive condition was used as a control. The oogenetic processes were similar in all species examined and classified into two phases according to the nuclear and ooplasmic characteristics: primary growth (PG) and secondary growth (SG) phases. The PG and SG phases were further divided into two and three substages, respectively. The occurrence of the ovotestis (6.66 %) in A. grunniens, suggested the environmental endocrine disruption in its habitat. Atretic oocytes (AO), characterised by the abnormal shape and degeneration of yolk granules and follicular complexes, in both PG and SG phases were observed. The AOs were found in all fishes, but the ratio was significantly higher in mesopelagic and estuarine fishes compared to other fishes. It is plausible that mesopelagic and estuarine fishes have poor reproductive health. The results of the study warrant further investigations on water quality associated with the long-term conservation efforts on the marine and estuarine ecosystems of Thailand.

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Date 2020/09/30

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