A study on seasonal dynamics of species diversity of fishes in tidal waters of creeks within the mangroves of Yingluo Bay, Guangxi

Abstract

Based on seasonal investigations by block net in 1999, the dynamics of species diversity of fishes in creek tidal waters within mangrove swamps of Yingluo Bay, Guangxi, were studied. Fifty four species of fishes, belonging to 44 genera and 29 families, were recorded. The numbers of species occurring in one to four seasons were 27, 8, 11 and 8, respectively. The dominant species in each season were very obvious, but the most dominant species differed in different seasons. The most dominant species were Clupanodon punctatus in spring, Osteomugil ophuyseni in summer, Ambassis gymnocephalus in autumn and Leiognathus ruconius in winter. As to their temperature tolerances, the warm-water species absolutely occupied the largest percentage. Numbers of demersal species were greater than other ecological types. Thirty species in spring, 30 in summer, 26 in autumn, and 22 in winter were captured in the creek waters. Twenty species were shared between summer and autumn, which was higher than that between any other pairs of seasons, This was also reflected in the similarity index between the two seasons, which reached 55/6% for the summer-autumn comparison. The indices of richness D, diversity H', and evenness J, were all higher in autumn than in other seasons. Numbers of fish species and the three biodiversity indices in creek tidal waters were all higher than that in mangrove-fringed tidal waters. The species diversity of the fish community in these waters was low in comparison with that in tropical mangrove areas. ～4的鱼类种数分别为27、8、11和8种。各季的优势种明显，但不同季节最大优势种不同，分别为：春季，斑鰶（Clupanodon punctatus）；夏季，前鳞骨鲻(Osteomugil ophuyseni)；秋季，眶棘双边鱼(Ambassis gymnocephalus)；冬季，鹿斑？(Leiognathus ruconius)。这些鱼类以暖水性种占绝对优势，在生态类型上以底层种类较多。各季节出现鱼类种数分别为：春季30种、夏季30种、秋季26种、冬季 22种。夏季与秋季共有种最多，有20个种，这两季节间的相似性指数也最大，达55.6%。多样性指数10、H'、J值均以秋季最高。相对于林外水域，红 树林潮沟鱼类群落的鱼类种数及3个指数均较高。跟热带红树林区相比，广西英罗港红树林潮沟鱼类群落的多样性低。