Occasional species are often neglected in community ecology studies due to low abundance and frequence. However, they are closely related to biodiversity maintenance and marine conservation. We used index of relative importance (IRI), distribution center of gravity and Mann-Kendall trend test to elucidate the spatial and temporal distributions and changing trends of occasional fishes in Haizhou Bay based on the fishery resources survey data collected from 2013 to 2019. The occasional fishes in Haizhou Bay was identified based on IRI. Nine of the occasional species were selected to analyze the spatial distribution and interannual trends of relative biomass and occurrence frequency. The results showed that a total of 93 fish species were recorded in the multi-year survey in Haizhou Bay. Among which, 61 species had IRI<10, indicating the existence of a large number of occasional fishes in Haizhou Bay. The nine selected occasional species had distinctive spatial distribution characteristics. Erisphex pottii, Azuma emmnion, and Raja porosa were mainly distributed in the eastern part of Haizhou Bay, with a wide habitat range. Sphyraena pinguis, Coilia nasus, and Zebrias zebra were distributed in the western and southern parts, respectively. The rest species were mainly distributed in the southwestern part. In terms of interannual variation, the biomass and occurrence frequency of Coilia mystus, R. porosa, A. emmnion, and S. pinguis showed fluctuating changes, while Odontamblyopus rubicundus and Ctenotrypauchen microcephalus showed an increasing trend. The biomass and occurrence of Z. zebra, C. nasus and E. pottii gradually decreased with no catch in recent years. This study would contribute to the understanding of the spatial and temporal distribution of occasional species, and provide guidance for the conservation of occasional biological resources and species diversity, especially for the establishment of marine protected areas.
偶见种由于其个体数或出现频率较少,在群落生态学研究中往往被忽略,但其与生物多样性维持和海洋保护具有紧密联系。为阐明海州湾偶见鱼类的时空分布特征及变化趋势,本研究基于2013—2019年海州湾渔业资源调查数据,使用相对重要性指数(IRI)、分布重心法和Mann-Kendall趋势检验等方法,分析海州湾偶见鱼类的种类组成,选取其中9个偶见种分析了其相对生物量的空间分布以及相对生物量和出现频率的年际变化趋势。结果表明: 海州湾多年调查捕获鱼类共93种,其中,IRI<10的鱼类有61种,表明海州湾存在大量偶见鱼类。选取的9个偶见种具有明显的空间分布特征,其中,虻鲉、繸鳚和孔鳐主要分布在海州湾东部海域,栖息范围广阔,油魣和刀鲚、带纹条鳎分别分布于海州湾西部、南部海域,其余主要分布在海州湾西南部海域。在其生物量的年际变化方面,凤鲚、孔鳐、繸鳚、油魣的生物量和出现频率呈现波动性变化,红狼牙虾虎鱼、小头栉孔虾虎鱼的生物量呈现上升趋势,带纹条鳎、刀鲚、虻鲉的生物量和出现频率均逐渐下降,近年再无捕获。本研究加深了对偶见种时空分布的理解,对保护偶见生物资源和物种多样性具有指导意义,为建立海洋保护区提供了科学支撑。.
Keywords: Haizhou Bay; Mann-Kendall trend test; biological resources protection; index of relative importance; occasional species.