Seasonal changes characterise the shark and ray assemblages in a subtropical shallow sandy habitat in the iSimangaliso Wetland Park, South Africa

PeerJ

article

Jessica A. Ferreira¹  Julie A. Alberts²  Grant Smith³  Anthony T.F. Bernard⁴  Mário J. Pereira⁶  Lauren De Vos⁷ 

[1] Departamento de Biologia, Universidade de Aveiro;Unaffiliated;Sharklife Conservation Group;Department of Zoology and Entomology, Rhodes University;SAIAB ,(South African Institute for Aquatic Biodiversity), Rhodes University;Departamento de Biologia & CESAM ,(Centre for Environmental and Marine Studies), Universidade de Aveiro;Save Our Seas Foundation

关键词: Elasmobranchs;    Species diversity;    Relative abundance;    Sandy habitat;    Environmental drivers;    Seasonality;    Stereo-BRUVs;   

DOI  :  10.7717/peerj.15636

学科分类：社会科学、人文和艺术（综合）

来源: Inra

【 摘 要 】

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 Carcharhinus humani prevalent in summer and the Critically Endangered whitespotted wedgefish Rhynchobatus djiddensis 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 C. humani and R. djiddensis 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.

【 授权许可】

CC BY