Ojwala Renis Auma, Otachi Elick Onyango, Kitaka Nzula Kivuva
Department of Biological Sciences, Egerton University, P.O. Box 536-20115, Egerton, Nakuru, Kenya.
Parasitol Res. 2018 Nov;117(11):3459-3471. doi: 10.1007/s00436-018-6042-0. Epub 2018 Aug 30.
Aquaculture has been documented as the fastest developing food industry in Kenya with increased production since the Government initiated the Economic Stimulus Programme (ESP) in 2009. However, the production has not yet reached the maximum level (20,000 metric tons per year) anticipated in the country. This is due to a number of challenges, top of which is poor water quality resulting from the uncontrolled addition of inputs (fish feeds, inorganic fertilizers, and organic fertilizers) into the ponds. These deteriorate water quality, cause increased incidences of parasite infections, and impede fish production. Therefore, this study investigated the effect of water quality on parasite assemblages infecting Oreochromis niloticus (Linnaeus 1758) in selected fish farms within Nakuru County from November 2016 to February 2017. Selected physico-chemical parameters namely: dissolved oxygen, temperature, pH, conductivity, and turbidity were measured in situ using appropriate meters. Water samples from each fish farm were analyzed for nutrient concentrations using standard methods. A total of 300 fish were examined for parasites. Parasites were counted, preserved, and identified using identification keys and parasitological parameters determined. The results indicated that certain water quality parameters, such as dissolved oxygen, were significantly different for all the six fish farms (one-way ANOVA, p < 0.05). A total of 15 species of parasites were recovered. Trichodina sp. and Cichlidogyrus halli were found in all the studied fish farms. Correspondence analysis revealed that some parasites' occurrences were highly correlated (positively) with certain water quality parameters. Therefore, regular monitoring and control of water quality in fish ponds are recommended to reduce levels of parasite infestations.
自2009年肯尼亚政府启动经济刺激计划（ESP）以来，水产养殖已被记录为该国发展最快的食品行业，产量不断增加。然而，产量尚未达到该国预期的最高水平（每年20,000公吨）。这是由于一系列挑战，其中最主要的是池塘中投入物（鱼饲料、无机肥料和有机肥料）不受控制地添加导致水质恶化。这些因素会降低水质，导致寄生虫感染发生率增加，并阻碍鱼类生产。因此，本研究调查了2016年11月至2017年2月期间，水质对纳库鲁县选定养鱼场中感染尼罗罗非鱼（Linnaeus 1758）的寄生虫群落的影响。使用适当的仪表现场测量选定的物理化学参数，即溶解氧、温度、pH值、电导率和浊度。使用标准方法分析每个养鱼场的水样中的营养成分浓度。共检查了300条鱼的寄生虫。对寄生虫进行计数、保存，并使用鉴定钥匙进行鉴定，并确定寄生虫学参数。结果表明，所有六个养鱼场的某些水质参数，如溶解氧，存在显著差异（单因素方差分析，p < 0.05）。共发现15种寄生虫。在所有研究的养鱼场中都发现了车轮虫属和哈利丽体虫。对应分析表明，一些寄生虫的出现与某些水质参数高度相关（正相关）。因此，建议定期监测和控制鱼塘水质，以降低寄生虫感染水平。
