Reproductive biology of the Ovalipes Portunidae punctatus （Crustacea：Decapoda：Portunidae） in the waters off northeastern Taiwan

• Main Authors: Su-Chiu Lo, 駱素秋
• Other Authors: Ping-Ho Ho
• Format: Others
• Language: zh-TW
• Published: 2011
• Online Access: http://ndltd.ncl.edu.tw/handle/48395022022843079261

碩士 === 國立臺灣海洋大學 === 環境生物與漁業科學學系 === 99 === Abstract The thesis studies the reproductive biology on Ovalipes punctatus in the waters off northeastern Taiwan.These preliminary results can be used as the input for stock assessment and management. In this study, a total of 1,405 specimens of crabs Ovalipes punctatus (824 females and 581 males) were random collected by monthly from Dec. 2009 to Dec. 2010 at Dasi fish market, Yilan county. These crabs were caught by trawlers at the depth of 100～200 m. Carapace width (CW) and body weight (BW) of Ovalipes punctatus specimens were ranged from 38.6～107.3 mm and 12.3～265.4 g, respectively. Between the male and female , the CW and BW relationship is significant differently. The relationship was expressed as BW = 0.0003（CW）2.8989 for females, and BW = 0.0003（CW）2.9696 for males. The mean BW of males was significantly larger than females, and chela length of males which sizes larger than 48 mm CW showed allometric growth. The total sex ratio was 1: 0.71. Ovigerous female specimens were obtained in all the year and the egg mass were developed over time. Gonadosomatic index, Coefficient of fatness and the percentage of ovigerous females indicate that mature females can be found all the year, and the major breeding season is from October to December. Sizes at the 50% sexual maturity CW are 67.9 mm for females, respectively. The smallest size of ovigerous crab was 45.1 mm. Batch fecundity of female Ovalipes punctatus ranged from 60,753 to 1,836,306 and mean batch fecundity was 857,207 eggs , with a mean diameter of 0.31± 0.04 mm.