Research Article Occurrence of Clinostomum Metacercariae in Oreochromis mossambicus from Mashoko Dam, Masvingo Province, Zimbabwe Casper Mutengu 1 and Wilson Mhlanga 2 1 Department of Biological Science, Bindura University of Science Education, Bindura, Zimbabwe 2 Department of Natural Resources, Bindura University of Science Education, Bindura, Zimbabwe Correspondence should be addressed to Wilson Mhlanga; wmhlanga63@gmail.com Received 10 May 2018; Accepted 20 September 2018; Published 15 November 2018 Guest Editor: John. F. Mupangwa Copyright © 2018 Casper Mutengu and Wilson Mhlanga. is is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Mashoko Dam is in Ago-ecological Region 4 in Zimbabwe. Five sampling sites were randomly selected and each site was sampled twice per month, for six months. A total of 180 Oreochromis mossambicus fish (101 females and 79 males) were caught. e fish were examined for Clinostomum metacercariae by cutting the ventral side from the anal opening to the lower jaw. e gill chambers were examined and inspected visually to detect macroscopic parasites. Of the 180 fish collected during the study, 113 (62.8%) were infected by 284 Clinostomum larvae in the cranial cavity while 67 fish were not infected. Among the infected fish, 46 were males and 67 were females. Greater parasite burden and mean intensity were observed in female fish (2.7 MI) than males (2.2 MI). ere was no statistically significant difference in mean intensity of infection between male and female fish (n � 180; t � 0.521; p < 0.05). Uninfected fish were in a poorer condition than infected fish in July and October only. e lowest monthly condition factor for both infected (1.8) and uninfected (1.7) fish occurred in October. e monthly condition factors for both infected (1.94–3.51) and noninfected fish (1.81–5.28) were greater than 1. For prevalence by total length groups, highest prevalence (66.3%) was recorded in the medium length group (10–12cm) and lowest (25.0%) in the (16–18cm) length group. Highest mean intensity (2.8) and parasite density (146 parasites) was observed in the length group (13–15cm) and lowest mean intensity (1.0) in largerlengthgroups(16–18cmandabove19cm).Highestabundance(1.74)wasrecordedinthelengthgroup13–15cmandlowest abundance (0.25) in the length group 16–18cm. Parasite burden was positively correlated to fish size (total length). It was concluded that Clinostomum metacercariae are a common parasite in Oreochromis mossambicus in Mashoko dam. 1. Introduction Parasites are common among fishes, affecting them in a variety of ways [1]. Fish parasites are among the key threats to the sustainability of fisheries that support about 90 million people around the world as a source of protein and income [2]. Parasitic infections of fish have human health, as well as socioeconomic implications, both in developing and de- veloped countries [3]. Parasites compete for food, thereby depriving fish of essential nutrients and inhibiting growth leading to morbidity and mortality with consequent eco- nomic losses [4]. Parasites also inflict damage on the hosts, sometimes causing gross mortalities, which can lead to great losses in commercial fisheries and aquaculture [5]. Fish parasites have the potential to affect fish through loss of blood and nutrients as well as the invasion of biochemical processes in the host fish [6]. In some cases, parasitised fish are so unsightly that they are rejected by consumers [6]. Studying parasites contributes towards a better un- derstanding of the ecology of a system and also helps to develop appropriate methods of controlling them [7]. Parasites render fish susceptible to secondary infection by disease-causing agents such as bacteria, fungi, and viruses [8]. e extent of fish infection by certain parasites can be used as an early warning indicator of deteriorating water quality [9]. e use of indicators allows evaluating the risk of exposure, acting as early warning systems for environmental deterioration [10]. Hindawi Scientifica Volume 2018, Article ID 9565049, 6 pages https://doi.org/10.1155/2018/9565049