| Summary: | 碩士 === 國立海洋大學 === 漁業科學系碩士在職專班 === 91 === Abstract
Reproductive biology of the blue sprate, Spratelloides gracilis in the waters off Peng-Hu was investigated by examining 7737 samples captured from March, 2001 to February, 2003. The lengthy spawning season extends from February to September based on the progressive changes of the size of ovaries stages, histological examination of ovaries, oocyte diameter measurements, and gonadosomtic index calculation. Ovaries development can be divided as four stages namely, undeveloped stage, developing stage, mature stage and spent stage. The average fecundity of this species was 2606±1678 with the mean batch fecundity of 1204±714. The relationships between fecundity (F) and fork length (FL) and batch fecundity (Fe) and fork length was F=0.0002FL0.38405 (r2=0.58), while the batch fecundity (Fe) and fork length (FL) was Fe=0.0001FL3.806 (r2=0.48). Length at first maturity was estimated to be 54.0mm FL base on the relationship between mature percentage and fork length. Sex ratio was significantly different from 0.5 with χ2 test.
Key words ： Spratelloides gracilis, fecundity,
batch fecundity. reroductive biology.
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