| Summary: | 碩士 === 國立臺灣大學 === 漁業科學研究所 === 87 === The specimens used in this study were sampled monthly at Kaohsiung Gusan Fish Market from the landing of the baby trawlers that operated in the Southern Taiwan Strait., i.e., Taiwan Bank from February 1998 to March 1999. This study investigated the maturity and spawning of lizard fish, Saurida undosquamis, using histological observation of ovary and oocyte analysis.
Oocyte development is divided into eight stages from histological observation, i.e., chromatin nucleolus stage, perinucleolus stage, cortical alveolus stage, primary yolk stage, secondary yolk stage, tertiary yolk stage, germinal vesicle migration stage, and preovulation stage. Ovary development is divided into six stages from the appearance and oocyte development styles in the ovaries, i.e., immature, developing, mature, spawning, spawned, and spent. Testis development is divided into three stages from the appearance of testis, i.e., immature, mature, and spawned. The oocyte distribution is asynchronus, so the lizard fish is a multiple spawner and can spawn all over a year. Two spawning peaks appear in April - May and November. The 50% mature fork length (ML50) is 30.8cm and 29.5cm for female and male, respectively. The sex ratio of total sample fish is 1:1, however, the female will increases when fork length increases. This study estimates batch fecundity by counting hydrated oocytes in the ovary. The batch fecundity is about 1,532 oocytes per grams of ovary weight or about 61,616 oocytes per fish. Under an assumption of the female with hydrated oocytes are spawning now, the spawning fraction is estimated as 0.34, or the females can spawn a time every 2.9 days.
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