Distribution and sediment preference of mudskippers in Wazihwei Nature Reserve

淡水河口的挖子尾自然保留區屬於潮間帶河口濕地生態系，蘊含著豐富的生物資源。彈塗魚類在濕地生態系中扮演了許多重要的角色，如穩固食物網的組成、環境污染的監測、評估河口濕地生態系的指標物種等。臺灣早期嚴重開發破壞濕地，近年雖訂立濕地保育法，推行國家重要濕地保育計畫，使濕地生態系逐漸受到重視，但台灣的濕地仍受到許多人為開發與破壞的壓力。目前國內彈塗魚相關研究十分缺乏，若欲知棲地改變會對彈塗魚造成什麼影響，需先了解其在灘地的分布及棲地偏好。本研究調查挖子尾地區彈塗魚的分布狀況，探討土壤含水量、底質粒徑大小、土壤有機物含量等底質環境因子對其分布的影響，並估算族群量，以做為濕地經營管理之參考。 結果顯示挖子尾地區共有三種彈塗魚分布，分別為青彈塗魚(Scartelaos histophorus)、大彈塗魚(Boleophthalmus pectinirostris)及跳彈塗(Periophthalmus modestus)。青彈塗魚數量最多，廣泛分布於挖子尾灘地，為該地區的優勢種彈塗魚；大彈塗魚調查到的數量次之，主要分布於低潮位水岸旁的開闊灘地；跳彈塗數量最少，僅零星分布於鄰近紅樹林邊緣的高潮位灘地。從底質環境因子分析顯示，三種彈塗魚對土壤含水量偏好有明顯差異，跳彈塗主要分布於土壤含水量較低的地區；大彈塗魚分布於含水量較高的灘地；青彈塗魚則從土壤含水量高到低的灘地皆有分布。三種彈塗魚對底質粒徑的偏好無明顯差異，皆分布於粒徑較小、偏向泥質的底質環境。大彈塗魚分布區域的土壤有機物含量顯著高於跳彈塗；土壤有機物含量高的樣區，大彈塗魚及青彈塗魚的數量也較多。 本研究是首次探討挖子尾地區彈塗魚分布和底質之間關係的研究，結果顯示挖子尾地區的彈塗魚在棲地底質選擇上的偏好是造成三種彈塗魚分布上差異的重要因素，且微棲地底質條件的差異會影響彈塗魚的數量及分布。了解彈塗魚對不同底質環境因子的偏好，可以更有效的評估泥灘地彈塗魚的分布狀況和族群數量，作為濕地復育經營管理之參考。Located at Tamsui estuary, Wazihwei Nature Reserve is a tidal mudflat ecosystem. With so many creatures blooming in this area, Wazihwei mudflat is one of the most valuable ecological wetland resources of Taiwan. Mudskippers are euryhaline and amphibious fish, and play important roles in tidal mudflats, Such as stabilizing the food web and considered as environmental pollutant indicator. Due to human development, anthropogenic disturbance and pollution, wetlands are currently deteriorating and disappearing at an accelerating rate. Therefore, understanding how environmental changes will influence the mudskippers requires more research; especially knowing the habitat preference of mudskippers. However, there is a lack of studies in Taiwan about the habitat preference of mudskippers. The factors that influence the distribution of mudskippers in the field are still unclear. This study focuses on how sediment conditions such as soil water content, particle size and soil organic content, affects the distribution of mudskippers in Wazihwei Nature Reserve. According to the result, three species of mudskippers were recorded in our study site, including Periophthalmus modestus, Boleophthalmus pectinirostris and Scartelaos histophorus. S. histophorus is the most abundant species which occupied almost the entire mudflat area. B. pectinirostris were found at open mudflat areas and the riverbank at low tide level. In contrast, only a few individuals of P. modestus were found scattered at the mangrove edge. There is significant preference of soil water content in three mudskippers. B. pectinirostris were distributed where the soil water content was high, and P. modestus were distributed near lower soil water content areas while S. histophorus were distributed across both high and low soil water content areas. There is no significant preference in sediment particle size for the three species of mudskippers since they all prefer fine sediment. On the other hand, B. pectinirostris were distributed where the soil organic content was high, P. modestus were distributed where the soil organic content was much lower. This research shows the different distribution of three mudskippers at Wazihwei Nature Reserve which is mainly due to their sediment preference. Understanding the habitat preference of mudskippers can evaluate and monitor their populations more efficiently. This study provides a preliminary research of mudskippers’ distribution and their sediment preference at Wazihwei wetland