厦门鳄鱼屿潮间带中国鲎的种群动态与底栖环境

为了解鳄鱼屿潮间带中国鲎资源状况,2018年6月—2019年5月,调查厦门鳄鱼屿潮间带中国鲎种群的个体数、软壳率、损伤率、头胸部长和宽、腹部长和剑尾长。结果表明:鳄鱼屿潮间带中国鲎个体数从2018年6月的12只增加到9月的37只,2018年12月和2019年1月未发现中国鲎,2019年3月增加到22只。2018年8—11月为中国鲎蜕壳期,2019年2—5月损伤率较高。2019年2月鳄鱼屿潮间带中国鲎种群的头胸部长和腹部长最大,分别为39.66 mm和31.20 mm,2019年5月头胸部长和腹部长最小,分别为22.93 mm和20.53 mm。2018年7月头胸甲宽和剑尾长最大,分别为60.42 mm和71.19 mm,2018年6月头胸甲宽和剑尾长最小,分别为43.93 mm和42.88 mm。厦门鳄鱼屿潮间带采集到大型底栖动物136种,优势类群主要是多毛类、甲壳类和双壳类。鳄鱼屿潮间带A、B、C 3个区的沉积物中均没有砾成分,从较高潮位(A区)到较低潮位(C区)砂和叶绿素a含量减少,而碳、氮、粉砂和黏土含量增加。由于受牡蛎养殖和池塘养殖等人类活动的影响,厦门鳄鱼屿潮间带的中国鲎种群及其栖息地较小。

Population Dynamics and Benthic Environment of Tachypleus tridentatus in the Intertidal Zone of Eyu Islet in Xiamen

To understand the status of horseshoe crab resources in the intertidal zone of Eyu Islet in Xiamen,the number of individuals,soft shell ratio,damage ratio,cephalothorax length and width,opisthosoma length and telson length of Tachypleus tridentatus were measured from June 2018 to May 2019.The number of T.tridentatus tended to increase from June(12 individuals)to September(37 individuals)in 2018.Tachypleus tridentatus was not found in December 2018 and January 2019,and the number increase to 22 by March 2019.The molting period mainly occurred from August to November 2018,and the high injury rate mainly occurred from February to May 2019.The mean cephalothorax length and opisthosoma length of the T.tridentatus population were both the largest in February 2019,with 39.66 mm and 31.20 mm,respectively,while they were both the smallest in May 2019,with 22.93 mm and 20.53 mm,respectively.The mean cephalothorax width and telson length were both the largest in July 2018,with 60.42 mm and 71.19 mm,respectively,while they were both the smallest in June 2018,with 43.93 mm and 42.88 mm respectively.A total of 136 species of benthic macrofauna were collected quantitatively in the intertidal zone.The dominant groups were polychaetes,crustaceans and bivalves.At A,B and C sites in the intertidal zone,there are no gravel,and the content of sand and chlorophyll decreases from the higher tide level(A site)to the lower low tide level(C site),while the content of carbon,nitrogen,silt and clay increases.Due to the influence of human activities such as oyster farming and pond fish farming,the T.tridentatus population and its habitat in the intertidal zone of Eyu Islet in Xiamen are both small.