英罗港红树林缘潮水中游泳动物的季节动态

应用大拦网（拦截水体约１０ｈｍ２）分季节研究了广西英罗港红树林缘潮水中的游泳动物。结果表明：４种软体动物、３种甲壳动物、４２种鱼类随潮水进入红树林缘滩涂。这些种大多是近海浅水种类。在４９种游泳动物中，最常见且数量大的有中华小公鱼、大眼青鳞鱼、印尼小公鱼、双边鱼、边鱼箴、黑斑、圆颌针鱼、勒氏银汉鱼和长毛对虾。鱼获的尾数和鲜重都是夏季＞秋季＞冬季＞春季，平均为７５４６６尾／网和３９．３８千克／网。体长小于１０ｃｍ的游泳动物的尾数和鲜重，平均分别占鱼获尾数的９３．９２％和鱼获鲜重的７０．８３％。以尾数和出现季节频度来衡量它们跟红树林生境的关系程度，可将４９个种大体上分成３类：关系程度较高的有９种，一般的有２０种，较低的有２０种。这些结果表明，红树林缘滩涂主要是近海浅水小型游泳动物或鱼苗的活动场所。跟热带红树林区相比，广西英罗港红树林缘潮水中鱼类群落的多样性低。

The Seasonal Dynamics of Nekton Assemblages in Mangrove-fringed Tidal Waters of Yingluo Bay, Guangxi

In Yingluo Bay of Guangxi, the nekton assemblages in mangrove-fringed tidal waters were seasonally sampled in 1994 by a large block net separating a water area of approximate 10ha. 4 species of molluscan, 3 species of crustacean and 42 species of fish were found to move into the mangrove-fringed intertidal zone with tide waters, and most of which were coastal shallow species. Of the 49 species, the most common and abundant species were Stolephorus chinensis, S. tri, Harengula ovalis, Ambassis sp., Hemirhamphus limbatus, Leiognathus daura, Tylosurus strongylurus, Atherina bleekeri and Penaeus penicillatus. The individual number and fresh weight of the collections were in the order of Summer > Autumn > Winter > Spring, with a mean of 75.466 ind/net and 39.38 kg/net. On an average, 93.92% of the total individuals had a body length in less than 10 cm, accounting for 70.83% of the total fresh weight of the collections. Combining individual number of each species and its seasonal occurring frequency, the 49 species can be broadly divided into three groups in terms of thier association with mangrove habitats. The relatively high extent is for 9 species, intermediate for 20 species, and relatively low for the rest species. It was indicated that mangrove-fringed zones were the important habitats for coastal shallow nektons of small size or fish seedlings. The diversity of the present fish community was low in comparison with that of tropical mangrove areas.