澎湖海域之鳴門奧螻蛄蝦生物學研究

Biology of the mud shrimp Austinogebia narutensis (Sakai 1986) (Crustacea: Decapoda: Thalassinidea: Upogebiidae) in Penghu

鳴門奧螻蛄蝦 Austinogebia narutensis 俗稱「蝦猴、猴仍」，為澎湖地區經濟物種之一。本研究探討其生物學特性，以期提供資源評估及生態保育等之具體資訊。在體型方面，最大的雌、雄蝦頭胸甲長為 19.49mm、21.07mm，體長為 66.38mm、67.61mm，其中雄蝦第一步足具大、小鉗之二型性現象。經比較分析，雌蝦與大、小鉗雄蝦三者的頭胸甲長對體長及第一步足掌節寬均為直線迴歸關係，而頭胸甲長對體重及第一步足重均呈曲線迴歸之關係，唯小鉗雄蝦各形質相關係數較低。此外，雌蝦最小性成熟體型之頭胸甲長為 12.61mm、體長為 40.07mm，卵巢在繁殖季前達最高峰，繁殖季開始時（11 月）逐漸下降，繁殖季結束（4 月）後則又上升。螻蛄蝦洞穴在離岸 15m 處開始發現，到離岸約 250m 處達洞口密度分佈高峰且密度為 232 尾∕m2。洞穴形狀呈 Y型，主要結構包含 U 型部（U-part）及 shaft 部（S-part），而次要結構則有迴轉室及側支，且洞穴在夏季時較深、開口間距較近。本種蝦整年卵巢均發育，推測應屬多次抱卵種類，且壽命至少為 2 年。 The mud shrimp Austinogebia narutensis, also known as “He-Gao” or “Gao-A”, is a commercial species in Penghu. This is a study of the biology and habitat of A. narutensis, and is intended to serve as a reference for relevant resources management and conservation in the future. The maximal carapace lengths (CL) of the species were 19.49 mm and 21.07 mm for female and male, respectively; while the body lengths (BL) were 66.38 mm and 67.61 mm for female and male, respectively. Adult males showed sexual dimorphism, including in both stout and slender chela. Results also showed high linear correlation in CL, BL and PwPI, as well as curvilinear correlation in CL, BW and PIW in female, and stout and slender chela in male. The minimal sexual maturity of female were 12.61mm and 40.07mm in CL and BL, respectively. Ovarian index (OI) revealed a decreasing trend in the breeding season beginning in November followed by an exponential growth in April the next year after the breeding season ended. The species' caves were at approximately 15 m and high density of caves occurred at 250m (232 ind/m2 ) from the coast. The caves were Y-shaped while their main structures were U-shaped (U-part) and shaft-shaped (S-part), with their secondary structures containing a turning chamber (tc) and side branch (br). The caves were deeper and the width of the orifices were narrower in the summer. With a lifespan of over two year, Austinogebia narutensis have ovaries that mature all year round, thus the species is considered a multi-spawning species.

The mud shrimp Austinogebia narutensis, also known as “He-Gao” or “Gao-A”, is a commercial species in Penghu. This is a study of the biology and habitat of A. narutensis, and is intended to serve as a reference for relevant resources management and conservation in the future. The maximal carapace lengths (CL) of the species were 19.49 mm and 21.07 mm for female and male, respectively; while the body lengths (BL) were 66.38 mm and 67.61 mm for female and male, respectively. Adult males showed sexual dimorphism, including in both stout and slender chela. Results also showed high linear correlation in CL, BL and PwPI, as well as curvilinear correlation in CL, BW and PIW in female, and stout and slender chela in male. The minimal sexual maturity of female were 12.61mm and 40.07mm in CL and BL, respectively. Ovarian index (OI) revealed a decreasing trend in the breeding season beginning in November followed by an exponential growth in April the next year after the breeding season ended. The species' caves were at approximately 15 m and high density of caves occurred at 250m (232 ind/m2 ) from the coast. The caves were Y-shaped while their main structures were U-shaped (U-part) and shaft-shaped (S-part), with their secondary structures containing a turning chamber (tc) and side branch (br). The caves were deeper and the width of the orifices were narrower in the summer. With a lifespan of over two year, Austinogebia narutensis have ovaries that mature all year round, thus the species is considered a multi-spawning species.