Abstract
此研究藉由阿美族原住民的傳統漁撈方法三角叉網與魚苗陷阱，於1995~1997三年期間記錄洄游性蝦虎魚苗於加入淡水階段的溯河動態與資源量變動，共記錄蝦虎魚科Gobiidae魚苗9屬11種，其中包括有2新記錄種，寬帶裸身蝦虎魚(Schismatogobius ampluvinculus)、羅氏裸身蝦虎魚(S.roxasi)。魚苗僅能在漲潮時刻從海洋進入秀姑巒溪中，且溯河族群消長呈月週期性(lunar rhythm)，造成此現象的原因在於出海口地形的限制以及與魚類本身的產卵週期、海洋時期有關。魚苗溯河為日行性其溯河速度約為1km/day。利用重複捕取的方法估算得1996年第一處魚苗陷阱的捕獲效率約0.52~0.28，當年魚苗總數中日本禿頭鯊(Sicyopterus japonicus)約544~1011萬尾、大吻蝦虎魚(Rhinogobius gigas)約2058~3822萬尾，其它魚種出現頻率相對很少。1996年第一處魚苗陷阱總漁獲物約1069.5公斤、1997年約669.3公斤，其中1996年漁獲物較多的主要原因為是該年魚苗陷阱使用兩個誘魚道而有較高的捕獲效率。個別魚種使用耳石技術建構其初期生活史，比較日本禿頭鯊、大吻蝦虎魚兩優勢魚種的生活史可發現，兩者藉由不同季節利用海洋棲息地、於淡水河川中則因有食性區隔而避免物種競爭並各自佔據獨特的生態區位(ecological nich)，日本禿頭鯊利用緩慢與長時間成長的策略渡過海洋秋冬低生產力時期，大吻蝦虎魚則配合春夏高生產力季節以快速成長完成海洋仔稚魚階段，而同時於河川高生產力的季節回到溪流生態系中。The thesis reports on three-years field study and records ofthe upstream migration behaviors and recruiting variation ofgobies fry resources by the Ami's conventional fishing means,the triangle-shape hand-nets and fish traps. In the study, werecord 9 genus, 11 species of Gobiidae, including two newlyrecorded species Schismatogobius ampluvinculus and S. roxasi.The high tide periods are the only windows available for gobyfries to enter the Hsuikuluan River from the Pacific Ocean.Moreover the recruiting population fluctuates along with lunarrhythm. Some suspected major factors that cause the phenomenonare as followed: geological restriction at the river mouth,spawning frequency and marine phase of the fishes. Goby friesare diurnally active and are estimated to migrate upstreamapproximately a kilometer per day. The results of capture-recapture method indicate that the efficiency of the fish trapis between 0.52~0.28, and that the total amounts of Sicyopterusjaponicus and Rhinogobius gigas are 544~1011 ten thousand and2058~3822 ten thousand, separately. In contrast, the otherspecies only contribute to considerably a very tiny proportion.Total harvesting in the first fish trap weighs 1069.5kg in 1996and 669.3kg in 1997. The higher gain in 1996 mainly resultedfrom the application of the twin fish traps at the same time.Early life histories of most species captured are constructed bytheir otoliths microstructure and microchemistry. Comparinglife histories of these two dominant species shows that theyavoid inter-species competition by using temporally alternativemarine habitats and by taking different bait in streams. Thesedifferences make they occupying distinct ecological niches. S.japonicus survives the barren fall and winter by lengthy marinestage with slower growth rate and R. gigas swiftly completes itsshort zooplantonic phase in the ocean, thereby these two speciesrecruit into freshwater ecosystem together in the highlyreproductive spring and summer .