Preliminary Survey of External Parasites: Crustacean and Monogeneans of Commonly Catched Fish Species in Lake Hayke of Amhara Region

Research Article

Ann Hematol Oncol. 2018; 5(8): 1221.

Preliminary Survey of External Parasites: Crustacean and Monogeneans of Commonly Catched Fish Species in Lake Hayke of Amhara Region

Tesfaye S, Enbiyale G*, Tesfaye A, Teshome D, Chanie M and Bogale B

Department of Veterinary Medicine, University of Gondar, Ethiopia

*Corresponding author: Enbiyale G, Department of Veterinary Medicine, University of Gondar, Gondar, Ethiopia

Received: September 14, 2018; Accepted: October 29, 2018Published: November 05, 2018


A cross study was conducted from November, 2015 to April, 2016 in Lake Lugo (Hayke), which is located in South WolloZone, northeast Ethiopia, with the aim of isolation and identifying the external parasites (crustacean and monogenean) from fresh water fish. A total of 124 randomly selected fishes comprising of 61 Oreochromis niloticus, 20 Clarias gariepinus and 43 Cyprinus carpio were examined for external parasites. The fish were examined thoroughly examined externally and sample of skin scraping and gills were taken for the presence of external parasite and lesion. From the total 124 fish species 23 (18.5%) fish species were infested with external parasite. From these infested fish species four external parasites which are three parasites of crustacean (Lerneaspp, Dolophusspp and Ergasilusspp) and one parasite of monogenean (Dactaylogyrusspp) were detected as the genes level. Prevalence of external parasites was higher in Clarias gariepinus (25%) followed by Cyprinus carpio (18.6%) and Oreochromis niloticus (18%) species. The statistical analysis showed that no statistically significant difference in among species, age and sex of fish (p>0.05). Based on this study crust aceans and monogeneans parasites have a great significance for the production of fish in the Hayke (Lake of Lugo) so it needs husbandry practice (water quality assessment and feed and feed delivery management), a serious control and preventive programs.

Keywords: Crustacean; Ethiopia; Fish; Isolation; Lake lugo; Monogenea


Ethiopia is endowed with many lakes and rivers comprising diverse aquatic ecosystems of great scientific interest and economic importance [1]. The country fish potential is estimated at 45,000- 51,500 tons per year. In 2008, fish catch was estimated at around 17,000 tons (accounting for about 1.7% of the regional volumes), the bulk of which (74%) originating from the six main lakes (Tana, Ziway, Langano, Hawassa, Abaya and Chamo) and a further 26% from the other water bodies. Thus, less than 38% of this potential is currently exploited, demonstrating considerable room for further expansion through proper management. Aquaculture is recognized as an alternative means of achieving food security and poverty reduction in the rural area, and is now considered an integral part of rural and agricultural development policies and strategies in Ethiopia [2,3].

A hundred local fish species have been identified, while the bulk of the production is made of Tilapia, Lates, Barbus, Bagrus, Clarias and Labeo species. Approximately 80% of the catch is Tilapia, although Nile perch is caught in large quantities on Lakes Chamo and Abaya, as well as in major riverine fisheries [4-7]. Lake Lugo (Hayke) provides a habitat to different fish species, water birds and aquatic organisms. The fish production potential of the Lugo Lake is estimated as 400 ton/year [8], and the off take rate is 83% as reported by FDRE (Federal Democratic Republic of Ethiopia).

Fish in wild and aquaculture farms face a wide range of enemies including competitors, predators and parasites. The major diseases associated with fish are parasites, bacteria, viruses and toxic algae that reduces fish production by affecting the normal physiology of fish and if left uncontrolled [9-12], it can results in mass mortalities or in some cases, can be serve as source of infection for human and other vertebrates that consumed fish. Parasites may induce a shift in fish species densities, size composition and affect commercially interesting stocks [13]. Ectoparasite infestations can cause severe skin damage such as abrasions and ulcerations on the body surface, hemorrhagic spots on the skin and eroded fins resulting in economic losses due to reduced growth, fecundity and increased morbidity and susceptibility to secondary infections [14-17].

Production in Ethiopia as other developing countries is strengthened by the availability of extensive inland water systems made up of streams, rivers and lakes that support a large number of fish species, many of which are of economic importance [18]. To fully develop and manage these diverse and rich fish resources in these inland water bodies, there is need for adequate knowledge of parasites that infect them with a view to adopting preventive and control measures to improve fish yield. However research commitments to the study of parasites of fresh water and marine fishes of the Ethiopia have been sporadic and inadequate considering the fish wealth of the countries. In Lake Lugo, little information is available on internal parasite of fish but there was no any researches have been conducted regarding to the external parasitic diseases of fish. There for the objective of this study is to identify crustacean and monogenean parasites of the three fish species (Tilapia, Catfish and Carp) in Lake Hayke of Amhara region.

Materials and Methods

Study area

The study was conducted on one of the high land Lakes of Ethiopia; Lake Lugo (Hayke) which is located in South Wollo Zone, Northeast Ethiopia. It is located 440km north of Addis Ababa, situated at 1101y5’N latitude, 39057’E longitudes, and at an altitude of 2030 M.A.S.L. The study area is categorized as sub-humid tropical with an annual rainfall of 1173 mm and a mean temperature of 18.2°C. The major rainy season is from July to September. Lugo Lake has an area of 23km² and a maximum depth of 88.2m and mean depth of 37.37m. The fishes that inhabit Lake Lugo are Oreochromis niloticus (Nile Tilapia), Clarias gariepinus (African catfish), and Cyprinus carpio (Common carp).

Study population

The study population consists of fish at different age, species and sex categories in the study area. According to the methods described by Paperna (47) the fishes were categorized into groups based on their weight (0.08-0.1 kg were classified as the fingerlings, 0.1-0.2 kg as juvenile, 0.21-0.3 kg as young and >0.31kg as adult fish) and sex organ. The sexes of the fish were determined using one or more of three procedures: (i) the abdomen of each fish specimen was pressed for the extrusion of whitish milt (for males) or eggs (for females). This approach was used if the fish was in ripe or running stage; ii) the fish was dissected for the presence or absence of testes or ovaries. Presence of testes signified maleness, while the presence of ovaries indicated that the fish was a female [19].

Study design and sample size

A cross-sectional study was conducted in Lake Hayke of Amhara region and random sampling technique was employed to select the samples after they are drawn from the water. Three hundred seventy two samples were taken from one hundred twenty four fishes. All the fish was caught using gill nets with mesh sieverangingf rom 60 to 120mm for sampling. All the specimens of fish were examined with in less than 12 hours of catch.

Data collection methods

The samples were collected immediately and observed externally from selected fresh specimens of Oreochromis niloticus, Clarias gariepinus and Cyprinus carpio recovered by local fishermen. After the samples were collected and purchased from fisher men then taken into the Kombolcha animal health investigation and diagnostic laboratory in ice boxes for parasitological examination and the sample were preserved with 10% formaldehyde. According to the procedure employed by Paternal, microscope and unaided eye were used for quick identification of ectoparasites on the external body surface (scales, gills, fins, opercula and eye) of the fish samples. Special note was taken of any damage to tissues/organs of the host by recovered parasites.

Data management and analysis

SPSS version 20 was used to analysis the collected data. The quantitative data was analyzed using descriptive statistics and the qualitative data was analyzed using descriptive statistics and compared as percentages, mean and frequency. Chi-square (X2) test was applied to compare the infestation status with regard to different variables like fish species, sex and age.


During the present study, 124 fishes were investigated for the presence of parasitic Crust aceans and Monogeneans. From a total of 124 fish sample, 23 fish (18.5%) were infested with ectoparasites. Through the parasitic serious examinations Lernea spp., Ergasilus spp., Dolophus spp. and Dactylogyrus spp. were detected (Table 3). The isolated parasites belonged to two Copepods, one Branchiura and one Monogeneafamilies. Fourteen and nine fish species were infested with Copepods, Branchiura and Monogenea respectively.

The results that explained in (Table 1,3) showed that from total percentage (18.5%) of detection 11.3% of detected parasites were Copepods (8.1% Lernea spp., 3.2% Ergasilus spp.), 3.2% were Brachuria (3.2% Dolophus spp.) and 4% were Monogenic Trematodes (4% Dactylogyrus spp.). Prevalence of 18%, 25% and 18.6%, were recorded from Oreochromis niloticus, Clarias gariepinus and Cyprinus carpio species, respectively, and the difference between species were not statistically significant at p>0.05 (Table 2). As indicated in (Table 2) males had higher prevalence of infection with parasite (19.7%) than their female counterparts (18.9%), but the difference between sexes were not statistically significant at P>0.05.