DD Khumbanyiwa, Kaunda, WL Jere, M. Limuwa, Davison Daniel, Khumbanyiwa
{"title":"从马拉湖迁徙到不同河流繁殖的 Opsaridium microlepis (Günther, 1864) 的形态变化","authors":"DD Khumbanyiwa, Kaunda, WL Jere, M. Limuwa, Davison Daniel, Khumbanyiwa","doi":"10.18697/ajfand.126.23445","DOIUrl":null,"url":null,"abstract":"Fish is an important resource in Malawi as a source of food for the majority as it provides affordable source of dietary animal protein as well as income. A number of fish species in the Malawi water bodies have their population dwindling. One of the species under serious threat of extinction is the Opsaridium microlepis - a potamodromous fish species that migrate to the rivers during its spawning period and its management seems a nightmare. A number of studies reveal contrasting results on genetic makeup and morphological aspect of this fish species. With changes in the ecosystems of the rivers connecting Lake Malawi, coupled with absence of strong management measures in the major rivers adjoining the lake, problems have arisen in the conservation of potamodromous fish species. This necessitated the present study to investigate if the morphological features of stocks of O. microlepis are the same or not and if they have changed to adapt to changes in the ecosystems. One hundred and eleven O. microlepis fish samples were collected from Linthipe River (48), Bua River (59) and North Rumphi River (4) monthly from March to August 2020 using trawled and static gillnets. Twenty-four morphometric characteristics were measured to determine if any morphological differences existed among the fish samples from the three rivers. Principal component analysis (PCA) was used to compare morphology of the fish. Results of the study showed no significant morphological differences among stocks from the three rivers, implying that O. microlepis in these rivers belong to same stock morphologically. The study reveals that the species do not differ morphologically even though they migrate to different rivers for breeding. The study further notes that numerous activities taking place along the tributary rivers (as observed during the study) such as modification of fishing gears as well as fishing methods and the deterioration of the spawning grounds due to siltation from soil erosion caused by deforestation and agriculture, are putting the potamodromous fish species such as O. microlepis under serious threat. The study recommends that the populations of O. microlepis from the rivers can be managed equally since they are morphologically similar. Adopting uniform catchment management and sustainable exploitation of O. microlepis (such as regulations on mesh sizes and fishing methods, closing the rivers from fishing activities during spawning period, river bank and catchment management and restoration) with the aim of conserving the stocks from further overexploitation in these rivers is recommended so that the communities and the people at large continue to utilize the resource sustainably and at the same time, sustaining their livelihood. 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One of the species under serious threat of extinction is the Opsaridium microlepis - a potamodromous fish species that migrate to the rivers during its spawning period and its management seems a nightmare. A number of studies reveal contrasting results on genetic makeup and morphological aspect of this fish species. With changes in the ecosystems of the rivers connecting Lake Malawi, coupled with absence of strong management measures in the major rivers adjoining the lake, problems have arisen in the conservation of potamodromous fish species. This necessitated the present study to investigate if the morphological features of stocks of O. microlepis are the same or not and if they have changed to adapt to changes in the ecosystems. One hundred and eleven O. microlepis fish samples were collected from Linthipe River (48), Bua River (59) and North Rumphi River (4) monthly from March to August 2020 using trawled and static gillnets. Twenty-four morphometric characteristics were measured to determine if any morphological differences existed among the fish samples from the three rivers. Principal component analysis (PCA) was used to compare morphology of the fish. Results of the study showed no significant morphological differences among stocks from the three rivers, implying that O. microlepis in these rivers belong to same stock morphologically. The study reveals that the species do not differ morphologically even though they migrate to different rivers for breeding. The study further notes that numerous activities taking place along the tributary rivers (as observed during the study) such as modification of fishing gears as well as fishing methods and the deterioration of the spawning grounds due to siltation from soil erosion caused by deforestation and agriculture, are putting the potamodromous fish species such as O. microlepis under serious threat. The study recommends that the populations of O. microlepis from the rivers can be managed equally since they are morphologically similar. Adopting uniform catchment management and sustainable exploitation of O. microlepis (such as regulations on mesh sizes and fishing methods, closing the rivers from fishing activities during spawning period, river bank and catchment management and restoration) with the aim of conserving the stocks from further overexploitation in these rivers is recommended so that the communities and the people at large continue to utilize the resource sustainably and at the same time, sustaining their livelihood. 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引用次数: 0
摘要
鱼类是马拉维的重要资源,是大多数人的食物来源,因为它提供了经济实惠的动物蛋白膳食来源和收入。马拉维水体中的一些鱼类物种数量正在减少。其中一种濒临灭绝的鱼类是 Opsaridium microlepis--一种在产卵期洄游到河流的钾洄游鱼类,其管理似乎是一场噩梦。多项研究显示,该鱼种的基因构成和形态方面存在着截然不同的结果。随着连接马拉维湖的河流生态系统发生变化,再加上毗邻马拉维湖的主要河流缺乏强有力的管理措施,洄游鱼类的保护出现了问题。因此,有必要开展本研究,调查小鳞鲑种群的形态特征是否相同,以及是否为适应生态系统的变化而发生了变化。2020 年 3 月至 8 月期间,使用拖网和静态刺网每月从林思培河(48 个)、布阿河(59 个)和北伦斐河(4 个)收集了 111 个 O. microlepis 鱼类样本。对 24 个形态特征进行了测量,以确定三条河流的鱼类样本之间是否存在形态差异。采用主成分分析法(PCA)对鱼类形态进行比较。研究结果表明,三条河流中的种群之间不存在明显的形态差异,这意味着这些河流中的 O. microlepis 在形态上属于同一种群。研究表明,即使这些鱼类洄游到不同的河流繁殖,它们在形态上也没有差异。研究进一步指出,支流河流沿岸发生的许多活动(如研究期间观察到的),如渔具和捕鱼方法的改变,以及森林砍伐和农业造成的水土流失导致的淤泥淤积造成的产卵场恶化,都使 O. microlepis 等钾洄游鱼类物种受到严重威胁。研究建议,由于小鳞鲤的形态相似,可以对河流中的小鳞鲤种群进行同等管理。建议采用统一的集水区管理和可持续开发方式(如规定网目尺寸和捕鱼方法、在产卵期禁止在河流中捕鱼、河岸和集水区管理与恢复),以保护这些河流中的鱼类种群,避免进一步过度开发,从而使社区和广大民众继续可持续地利用资源,同时维持生计。关键词钾洄游鱼类、Linthipe 河、Bua 河、North Rumphi 河、主成分分析
Morphometric variations among Opsaridium microlepis (Günther, 1864) from Lake Malaŵi migrating to different rivers for breeding
Fish is an important resource in Malawi as a source of food for the majority as it provides affordable source of dietary animal protein as well as income. A number of fish species in the Malawi water bodies have their population dwindling. One of the species under serious threat of extinction is the Opsaridium microlepis - a potamodromous fish species that migrate to the rivers during its spawning period and its management seems a nightmare. A number of studies reveal contrasting results on genetic makeup and morphological aspect of this fish species. With changes in the ecosystems of the rivers connecting Lake Malawi, coupled with absence of strong management measures in the major rivers adjoining the lake, problems have arisen in the conservation of potamodromous fish species. This necessitated the present study to investigate if the morphological features of stocks of O. microlepis are the same or not and if they have changed to adapt to changes in the ecosystems. One hundred and eleven O. microlepis fish samples were collected from Linthipe River (48), Bua River (59) and North Rumphi River (4) monthly from March to August 2020 using trawled and static gillnets. Twenty-four morphometric characteristics were measured to determine if any morphological differences existed among the fish samples from the three rivers. Principal component analysis (PCA) was used to compare morphology of the fish. Results of the study showed no significant morphological differences among stocks from the three rivers, implying that O. microlepis in these rivers belong to same stock morphologically. The study reveals that the species do not differ morphologically even though they migrate to different rivers for breeding. The study further notes that numerous activities taking place along the tributary rivers (as observed during the study) such as modification of fishing gears as well as fishing methods and the deterioration of the spawning grounds due to siltation from soil erosion caused by deforestation and agriculture, are putting the potamodromous fish species such as O. microlepis under serious threat. The study recommends that the populations of O. microlepis from the rivers can be managed equally since they are morphologically similar. Adopting uniform catchment management and sustainable exploitation of O. microlepis (such as regulations on mesh sizes and fishing methods, closing the rivers from fishing activities during spawning period, river bank and catchment management and restoration) with the aim of conserving the stocks from further overexploitation in these rivers is recommended so that the communities and the people at large continue to utilize the resource sustainably and at the same time, sustaining their livelihood. Key words: Potamodromous, Linthipe River, Bua River, North Rumphi River, principal component analysis
期刊介绍:
The African Journal of Food, Agriculture, Nutrition and Development (AJFAND) is a highly cited and prestigious quarterly peer reviewed journal with a global reputation, published in Kenya by the Africa Scholarly Science Communications Trust (ASSCAT). Our internationally recognized publishing programme covers a wide range of scientific and development disciplines, including agriculture, food, nutrition, environmental management and sustainable development related information.