Knochel Anna M, Hussey Nigel E, Kessel Steven T, Braun Camrin D, Cochran Jesse E M, Hill Graham, Klaus Rebecca, Checkchak Tarik, Elamin El Hassen Nasereldin M, Younnis Mohammed, Berumen Michael L
Red Sea Research Center, Division of Biological and Environmental Science and Engineering, King Abdullah University of Science and Technology, Thuwal, 23955, Kingdom of Saudi Arabia.
Department of Integrative Biology, University of Windsor, 401 Sunset Avenue, Windsor, ON, Canada.
Mov Ecol. 2022 Apr 28;10(1):22. doi: 10.1186/s40462-022-00314-9.
Reef manta ray (Mobula alfredi) populations along the Northeastern African coastline are poorly studied. Identifying critical habitats for this species is essential for future research and conservation efforts. Dungonab Bay and Mukkawar Island National Park (DMNP), a component of a UNESCO World Heritage Site in Sudan, hosts the largest known M. alfredi aggregation in the Red Sea.
A total of 19 individuals were tagged using surgically implanted acoustic tags and tracked within DMNP on an array of 15 strategically placed acoustic receivers in addition to two offshore receivers. Two of these acoustically monitored M. alfredi were also equipped with satellite linked archival tags and one individual was fitted with a satellite transmitting tag. Together, these data are used to describe approximately two years of residency and seasonal shifts in habitat use.
Tagged individuals were detected within the array on 96% of monitored days and recorded an average residence index of 0.39 across all receivers. Detections were recorded throughout the year, though some individuals were absent from the receiver array for weeks or months at a time, and generalized additive mixed models showed a clear seasonal pattern in presence with the highest probabilities of detection occurring in boreal fall. The models indicated that M. alfredi presence was highly correlated with increasing chlorophyll-a levels and weakly correlated with the full moon. Modeled biological factors, including sex and wingspan, had no influence on animal presence. Despite the high residency suggested by acoustic telemetry, satellite tag data and offshore acoustic detections in Sanganeb Atoll and Suedi Pass recorded individuals moving up to 125 km from the Bay. However, all these individuals were subsequently detected in the Bay, suggesting a strong degree of site fidelity at this location.
The current study adds to growing evidence that M. alfredi are highly resident and site-attached to coastal bays and lagoons but display seasonal shifts in habitat use that are likely driven by resource availability. This information can be used to assist in managing and supporting sustainable ecotourism within the DMNP, part of a recently designated UNESCO World Heritage Site.
沿非洲东北海岸线的礁蝠鲼（Mobula alfredi）种群研究较少。确定该物种的关键栖息地对于未来的研究和保护工作至关重要。苏丹的敦戈纳布湾和穆卡瓦尔岛国家公园（DMNP）是联合国教科文组织世界遗产地的一部分，拥有红海已知最大的礁蝠鲼聚集区。
总共19只个体被使用手术植入的声学标签进行标记，并在DMNP内通过15个精心布置的声学接收器阵列以及两个近海接收器进行跟踪。其中两只接受声学监测的礁蝠鲼还配备了卫星链接档案标签，一只个体装有卫星发射标签。这些数据共同用于描述大约两年的居留情况以及栖息地利用的季节性变化。
在96%的监测日内在阵列中检测到了带标签的个体，所有接收器的平均居留指数为0.39。全年都有检测记录，尽管有些个体一次会有几周或几个月不在接收器阵列中，广义相加混合模型显示出明显的季节性模式，在北半球秋季检测到的概率最高。模型表明，礁蝠鲼的出现与叶绿素-a水平的升高高度相关，与满月的相关性较弱。包括性别和翼展在内的模拟生物因素对动物的出现没有影响。尽管声学遥测表明居留率很高，但卫星标签数据以及在桑加内布环礁和苏埃迪海峡的近海声学检测记录到个体移动到距离海湾达125公里处。然而，所有这些个体随后都在海湾中被检测到，表明该地点具有很强的地点保真度。
当前研究进一步证明了礁蝠鲼高度居留且附着于沿海海湾和泻湖，但在栖息地利用上表现出季节性变化，这可能是由资源可用性驱动的。这些信息可用于协助管理和支持DMNP内的可持续生态旅游，DMNP是最近指定的联合国教科文组织世界遗产地的一部分。
