Departamento de Biologia, Universidade de Aveiro, Aveiro, Portugal.
Unaffiliated, Tampa, FL, United States of America.
PeerJ. 2023 Jul 14;11:e15636. doi: 10.7717/peerj.15636. eCollection 2023.
Understanding how environmental drivers influence shark and ray spatial and temporal patterns can provide crucial knowledge for their evidence-based protection and long-term monitoring. However, information on which drivers of variation are most important for elasmobranch communities on soft sediments is limited. Using baited remote underwater stereo-video systems (stereo-BRUVs), we investigated how seasonal and environmental variables affected the elasmobranchs of the iSimangaliso Wetland Park marine protected area (MPA) in South Africa (SA). In total, 11 species were identified from 48 sites between 12 m and 33 m water depth in a sandy habitat. While species richness was similar across seasons, the total abundance of elasmobranchs recorded was higher in winter than summer. The species assemblage composition varied significantly between seasons, with the Human's whaler shark prevalent in summer and the Critically Endangered whitespotted wedgefish more abundant during winter. Most species were sighted throughout the entire depth range, but rays were more common in shallower waters (< 25 m depth), while and were more common in the deeper depth zone of this study. This research provides baseline information about this previously unexplored sandy habitat for elasmobranchs in a site of regional and global significance. Records of species of conservation concern in the sampling area highlight the importance of protecting sand environments within an MPA.
了解环境驱动因素如何影响鲨鱼和鳐鱼的时空模式,可以为基于证据的保护和长期监测提供关键知识。然而,关于哪些驱动因素对软沉积物上的鳐鱼群落最重要的信息有限。我们使用诱饵远程水下立体视频系统(立体 BRUVs),研究了季节性和环境变量如何影响南非 iSimangaliso 湿地公园海洋保护区(MPA)的鲨鱼和鳐鱼。在总共 48 个站点中,在 12 米至 33 米水深的沙质生境中,共鉴定出 11 个物种。尽管各季节的物种丰富度相似,但冬季记录的鲨鱼和鳐鱼总丰度高于夏季。季节之间的物种组合组成差异显著,夏季常见人类抹香鲸鲨,冬季 Critically Endangered whitespotted wedgefish 更为丰富。大多数物种在整个水深范围内都有发现,但鳐鱼在较浅的水域(<25 米深)更为常见,而 和 在本研究的较深水深区更为常见。这项研究为该地区以前未探索过的沙质生境中鲨鱼和鳐鱼提供了基线信息。在采样区域记录到具有保护意义的物种,突出了保护 MPA 内沙质环境的重要性。