大陈岛海域潮下带岩礁生境鱼类群聚特征

Characteristics of fish assemblages in subtidal rocky reef habitats around Dachen Islands

摘要:

为了解大陈岛海域岩礁生境的鱼类群聚特征，2020年9月至2021年4月每个季度1次，采用多网目组合刺网对该海域的潮下带岩礁生境进行了鱼类样本采集，利用Jaccard相似性指数、相对重要性指数、α多样性指数、聚类和排序以及典型对应分析等多元统计方法对该生境鱼类群聚特征及其与环境因子的相互关系进行了研究。结果显示：在大陈岛潮下带岩礁生境共采集鱼类49种，隶属于10目27科40属，其中石首鱼科和鳀科的比例最高，分别为22.45%和10.20%。全年共出现优势种鱼类11种，褐菖鲉（Sebastiscus marmoratus）、鳞鳍叫姑鱼（Johnius distinctus）和丝背细鳞鲀（Stephanolepis cirrhifer）等鱼类优势度较高，其中褐菖鲉为全域全年优势种。多元统计结果表明：空间上不同类型站点之间均有不同程度的相异性，其中养殖区域及东部岩礁区形成了与其他区域差异显著的群聚特征（P<0.05）；时间上亦呈现出明显的季节变化（P<0.05）。多样性表现上，夏季鱼类多样性最高，冬季最低。典型对应分析表明：盐度和温度是影响大陈岛岩礁生境鱼类群聚的最显著因子。在局地水平的研究发现养殖干扰区周边的岩礁生境呈现出更为稳定且多样的鱼类群聚格局，但总体上大陈岛潮下带岩礁的鱼类群聚组成简单、结构相对脆弱，亟需建立针对性的保护和管理措施。

Abstract:

To comprehend the fish assemblage characteristics of the rocky reef habitats in the sea area of Dachen Islands， we collected fish samples from the subtidal rocky reef habitats using gillnets with multiple mesh， once per season from September 2020 to April 2021. Multiple statistical methods， including Jaccard similarity index， relative importance index， α-diversity index， clustering and ordination， and canonical correspondence analysis， were employed to investigate the characteristics of fish assemblages in this habitat and their relationship with environmental factors. A total of 49 fish species were collected from the subtidal rocky reef habitats of Dachen Islands. These species belong to 10 orders， 27 families， and 40 genera. The highest proportions were found in the Sciaenidae family （22.45%） and the Engraulidae family （10.20%）. Eleven dominant species appeared throughout the year， with Sebastiscus marmoratus， Johnius distinctus， and Stephanolepis cirrhifer exhibiting high dominance. The multivariate statistics results indicate significant spatial and temporal differences in fish communities in subtidal reef habitats on Dachen Islands. Different degrees of dissimilarity between various site types were observed， with the aquaculture areas and eastern rocky reefs forming assemblages that differed significantly from other areas （P<0.05）. Additionally， significant seasonal variations were observed （P<0.05）， with the highest biological diversity observed in summer and the lowest in winter. Canonical correspondence analysis identifies salinity and temperature as the most significant factors influencing fish assemblages in the rocky reef habitats of Dachen Islands. On a local scale， the study reveals that rocky reef habitats around aquaculture disturbance areas exhibit more stable and diverse fish assemblage patterns. The negative impact of aquaculture activities on fish assemblages is currently not significant， and fish within these habitats may have already developed adaptive strategies to cope with human disturbances. But in general， the fish assemblage composition of subtidal reefs was simple and structurally fragile， emphasizing the urgent need for targeted conservation and management measures.