Tibihika Papius Dias, Curto Manuel, Meimberg Harald, Aruho Cassius, Muganga George, Lugumira Jerome Sebadduka, Namulawa Victoria Tibenda, Aanyu Margaret, Ddungu Richard, Ondhoro Constantine Chobet, Okurut Tom
National Agricultural Research Organization (NARO), National Fisheries Resources Research Institute (NaFIRRI), Aquaculture Research and Development Centre Kajjansi (ARDC), P.O. Box 530, Kampala, Uganda.
University of Natural Resources and Life Sciences Vienna (BOKU), Department of Integrative Biology Research, Institute for Integrative Nature Conservation Research, Gregor Mendel Straße 33, 1180, Wien, Austria.
BMC Zool. 2023 Nov 23;8(1):28. doi: 10.1186/s40850-023-00190-9.
Various anthropogenic activities continue to threaten the fish biodiversity of the East African water bodies such as the Victoria Nile. Although the Victoria Nile is a significant source of livelihood for human populations, the biology and ecology of Nile tilapia in this ecosystem remain understudied with little or no information on the morphology of the fish given varying and immense anthropogenic activities. Here, we use geometric morphometrics to examine the morphology/shape variations of Nile tilapia populations in Victoria Nile to gain insights into their current ecological state.
Our results indicate unexpectedly smaller Nile tilapia body weights in Victoria Nile than in L. Victoria. Despite this, nearly all the populations displayed a relative condition factor (Kn) of greater ≥1 suggesting a healthy stock. However, two populations, LMF and VN_Bukeeka demonstrated Kn values of less than one (< 1). We also report that some Upper and Lower Victoria Nile populations display morphological similarities. Apart from L. Albert, Nile tilapia populations from Lakes Victoria and Kyoga are morphologically divergent from the riverine ones. We note that Nile tilapia from Nalubale Dam Reservoir is morphologically distinct from the close neighbouring Victoria Nile populations which are likely allied to the influence of the Nalubale Hydroelectric power dam as a barrier.
Nile tilapia's morphological variation appears to be influenced by various anthropogenic disturbances notably, overfishing, hydroelectric power dams, and fish translocational history in Uganda. Management should enforce regulatory frameworks to avert human-mediated activities as these are likely to compromise the sustainability of the fisheries. Further studies are required to follow these populations with molecular genetics and environmental data to gain a deeper understanding of the fish species for informed sustainable management and conservation options.
各种人为活动持续威胁着东非水体（如维多利亚尼罗河）的鱼类生物多样性。尽管维多利亚尼罗河是当地居民重要的生计来源，但在这个生态系统中，尼罗罗非鱼的生物学和生态学仍未得到充分研究，鉴于人为活动的多样和巨大影响，关于这种鱼的形态学信息很少或几乎没有。在这里，我们使用几何形态测量学来研究维多利亚尼罗河中尼罗罗非鱼种群的形态/形状变化，以深入了解它们当前的生态状态。
我们的结果意外地表明，维多利亚尼罗河中尼罗罗非鱼的体重比维多利亚湖中的更小。尽管如此，几乎所有种群的相对条件因子（Kn）都≥1，表明种群健康。然而，有两个种群，即LMF和VN_Bukeeka的Kn值小于1。我们还报告说，维多利亚尼罗河上下游的一些种群表现出形态上的相似性。除了艾伯特湖，维多利亚湖和基奥加湖的尼罗罗非鱼种群在形态上与河流中的种群不同。我们注意到，纳卢巴莱大坝水库的尼罗罗非鱼在形态上与邻近的维多利亚尼罗河种群不同，这可能与纳卢巴莱水电站大坝作为屏障的影响有关。
尼罗罗非鱼的形态变化似乎受到各种人为干扰的影响，特别是过度捕捞、水电站大坝以及乌干达的鱼类迁移历史。管理部门应加强监管框架，以避免人为介导的活动，因为这些活动可能会损害渔业的可持续性。需要进一步开展研究，利用分子遗传学和环境数据跟踪这些种群，以便更深入地了解该鱼类物种，从而制定明智的可持续管理和保护方案。
