The inland fishery of Africa contribution is estimated to be about 2.1 million tonnes of fish per year, it represents 24% of the total world fish production from inland water bodies (FAO, 2004). In Ethiopia, fish comes exclusively from inland water bodies including lakes, rivers, streams, reservoirs and substantial wetlands that are of great socio-economic, ecological and scientific importance (Janko, 2013, 2014; Tesfaye and Wolff, 2014). The overall potential yield of fish in Ethiopia water bodies are estimated as 94,500 tons per year on average (Tesfaye and Wolff, 2014). Water bodies located in the Rift Valley show signs of overexploitation whereas those located in remote areas with poor infrastructure which make up the majority remain underutilized (Janko, 2014; Tesfaye and Wolff, 2014). Hence, the existing role of fishery is insignificant in the country’s overall economy because the fishery sector in the country is far below its potential (Kebede et al., 2017). The current production is still far below the estimated potential yield, which suggests the possibility for further expansion of the fishery.

Ethiopia is endowed with several water bodies that contain a high diversity of aquatic fauna. Reservoir fishery plays  an  important  role  in  the  economy  of  the country and the livelihoods of the people living adjacent to those reservoirs. Fisheries resource in Ethiopia, in spite of its significant contribution to poverty alleviation and food security, is an unexploited natural resource (Kebede et al., 2017). Ethiopia has many lakes and reservoirs of which Denbi reservoir (Denbi Mini Hydro Electric Power plants) located in Bench Maji Zone forms a part. Denbi reservoir is estimated to have an area of 72 km², and a fishery potential of 383 tonne/year (Janko, 2014). The reservoir is fitting for fishery and aquaculture development to supply fish for the community. However, there is a lack of information on fish captured method, challenges and opportunities for proper utilization of the reservoir for sustainable utilization and development of the fish sector in the area. Therefore, this study sets to assess fish captured method, challenges and opportunities of fish production of Denbi reservoir.

Description of the study area

The study was conducted in Denbi reservoir which is located in Bench-Maji zone in the boundary between Fanika Kebele of South Bench and Fajika Kebele of ShekoWereda in South Western part of Ethiopia as shown in Figure 1. In addition to generating electricity, the fry fish of Nile tilapia (Oreochromis niloticus (Linnaeus, 1758)) and Redbelly tilapia (Coptodon Zilli (Gervais, 1848)) has been introduced in the dam in 1995 aimed to supply fish for the surrounding community.   People    found    around   the   reservoir economically depends mainly on production of coffee, fruits (Banana, Avocado, Mango), maize, Enset and subsistence mixed crop livestock. Fishing in the reservoir was not an open accesses and only legally registered cooperatives members were allowed to capture fish.

Sampling methods and size

Before implementation of the actual survey, exploratory field observations were conducted around the reservoir to decide sample size. During the field survey period it was observed that Denbi reservoir was a restricted area and fishing were permitted for legalized fishery cooperative members only. The community did not have an access to fish unless illegally. Based on this fact, in addition to fishery cooperative members, households nearby the reservoir, key informants and elders, and guard workers of the reservoir were selected to gather information for the study. Accordingly, all fishery cooperatives members (11) were included in the study. Though households near the reservoir were not involved in the fishing practices, 22 key informants and elders (12 members from Fanika Kebele (Village) and 10 from Fajika Kebele (Village)) were selected for focus group discussions to have diversified information and to triangulate the collected data. In addition, 10 guard workers of the reservoirs were randomly interviewed. The overall sample size was 43 (22 from two Kebeles (Fanika and Fajika), 11 fishery cooperatives member and 10 guards). Moreover, personal observation also made to gather information.

Data collection methods

The data were collected using semi structured questionnaire interview; focus group discussion and field observations. Field observation was undertaken focused on the other agricultural practices around the reservoir catchment, human and animal interaction to the reservoir, type of fishing gears and the infrastructures for fishery activities. Secondary data were also collected through review of relevant literature. Data on the socio-economic status, fish consumption, fish utilization and marketing systems, fishing methods, fish handling and processing methods, challenges and opportunities of fish production of the reservoir were assessed.

Data analysis

The data were analyzed by combining quantitative and qualitative methods. Descriptive statistics was used to summarize and analyze the quantitative data obtained by questionnaires using SPSS V.20.

Socio-economic characteristics

The socio-economic characteristics of the fishery cooperative members were assessed during the study period. There was only one legally registered fishery cooperative having a total of eleven members in Denbi reservoir as indicated in Table 1. Majority (81.8%) of the fishery cooperative members were men. The age of the fishery cooperative members ranges from 18 to 35 years. The educational back ground of the cooperative members indicated all of them had attended primary school education. Majority (72.7%) of the fishery cooperative members had three years of experience in fishing activity though fishing were not their major income sources rather production of Maize, Coffee, Fruits, Taro and Enset. Division of labor among men and women cooperatives members were observed; women cooperative members were engaged in washing mesh, processing, transporting and selling of the captured fish while men were mainly involved in capturing. This result confirms those reported from some parts of the country like Gambella, where women are actively involved in fishing to secure their family’s daily food requirements and to cover household expenditures (Tesfaye and Wolff, 2014). The labor division of women not to participate in fish capturing might be due to frustration from sinking down and lack of experience and skill to swim and barging.

Fish harvesting and purpose of fishing

Fish were captured once in two days using non-motorized single boat and gillnets of 50 m length, 2 m width and mesh size of 6 to 8 cm. The peak capture yield was obtained from May to September with the maximum yield ranging from 50 to 60 fish per capture of dominant species of O. nilotics whereas the lowest ranged between Octobers and April in year 2016/2017 with yield ranging from 10 to 15 fishes per capture. However, the production is below the estimated potential (Janko, 2014). Similar report by Kebede et al. (2017), Nile Tilapia (O. niloticus) is the dominant fish species of the landings in different part of the country. According to the respondent, all fishermen used fish for income generation. However, the fishermen got additional income other than fishing in agreement with the report of Abelti et al. (2014). Fishing in the study area is mainly dependent on wild capture with no contribution from aquaculture activities. According to the response obtained from the focus group discussion, fish was captured illegally during the winter using different techniques such as chemical processed from seeds of Birbira tree (Millettia ferruginea). Similar reports by Tesso et al (2017) and Agumassie (2018) indicated the utilization of M. ferruginea by fishermen in Sale Nono district on River Ganji and different part of Ethiopia. According to the response of guards, fishing was not open access to anybody rather to legally registered cooperatives, due to the shortage of fishing gears and less emphasis and skill gap of the cooperatives to capture on the daily bases the resources was underutilized.

Fish handling, storage and preservation

The fishing activity in Denbi reservoir was not intensive only one  legally registered  fishery  cooperative  member involved in fishing and it was restricted for other community. The processing method used by the fishermen cooperatives mainly gutting. The captured fish was processed in and around the reservoir whilst the by-products and waste materials were dumped into the reservoir as shown in Figure 2. Smoking was reported as the main means of preservation by the community. The fishermen methodically tied the fish upper lip with thread/twine then place the fish underneath the water to keep the fish fresh until it was purchased.

Transportation and marketing of fish

The gutted fish were either screwed on stick or kept in icebox and transported on foot by two persons to the nearby market and village. The cooperative fixed the price of fish based on its size. Fish processing (value addition) was not practiced as the fishermen sold the fish in the raw state. It was also reported that there was no religious and cultural restriction on the consumption of fish in the study areas. Moreover, the demand for the fish was not affected by season in the study area. It was reported that there was low captured potential and low supply of fish. Fish consumption tends to be based on locally and seasonally available products, with supply driving the fish chain (FAO, 2014).

Fish production constraints and challenges

The fishery coopertatives listed and ranked the different constraints for fish production in the study area as presented in Table 2. Shortage of fishing gears, lack of motorized boat, and retarded growth of fish as well as decrease of yield were ranked from first to third, respectively. There was also no clear border between the reservoir  catchment  area  and   the  agricultural  land  of surrounding communities which may pose a threat for the sustainable utilization of the reservoir. This finding is in line with that of Abegaz et al. (2010) and Abelti et al. (2014) in which lack of transportation facilities, proper fishing gears was cited as the main constraints to fish production in different region of Ethiopia. Similarly, lack of modern fishing tools and illegal fishing gears are also the challenges of fisheries of South Wollo Lakes (Assefa and Kelemework, 2013). Based on observation, there were intensive agricultural activities and deforestation around the Denbi reservoir that may lead the reservoir has been filled by flood/sedimentation and which results in poor productivity of fish as shown in Figure 3. In agreement with the report of Agumassie (2018), expansion of agriculture and deforestation were the current problems of Ethiopian fishes and fishery. In general, the Ethiopian fishery is under several constraints due to different factors (Kebede et al., 2017; Mathewos and Abebe, 2016).

Opportunity for development

There is an opportunity to maximize the fish production in the study area because there is high demand for fish in the area. Similar report showed that the demand for fishes is increasing double in Ethiopia (Mathewos and Abebe, 2016). Furthermore, there are no seasonal and religious effects on fish consumption pattern and availability of water through the year. The mentioned opportunities may increase the income of fishermen when they will give an emphasis to improve the productivity. Increasing number of fishermen to exploit the fish potential of the reservoir is important to increase the income of the society. Similarly, the current production in Ethiopia is still far below the estimated potential yield, which suggests scope for further expansion of the fishery (Tesfaye and Wolff, 2014). Thus, fishery and aquaculture in Ethiopian is recognized as an alternative means of achieving food security in particular and poverty reduction in general, and is now considered as an integral part of rural and agricultural development strategies (Kebede et al., 2017).

Fish production system of the reservoir was categorized as extensive with low labor and economic inputs resulting in low productivity. Fishing in the reservoir was conducted by legally registered fishermen cooperative each other day, though illegal fishing takes place. The captured fish degutting was the major post-harvest process undertaken by the fishermen. Fish processing (value addition) was not practiced and the fishermen sold whole fish. There was no religious and cultural restriction on the consumption of fish in the study areas. Moreover, the demand for the fish was not affected by season in the study area. There were several constraints affecting fishery and fish production of the reservoir including shortage of fishing gear and lack of motorized boat were the first and second ranked, respectively. Fishing in Denbi reservoir should be commercialized, additional fisher cooperative/fishermen should be increased, fishing technologies should be improving and further study on aquaculture establishment should be undertaken for the development and utilization of the resources in the area.

The author would like to express their appreciation to Mizan-Tepi University for funding this study. They would further express their appreciation to the households, fishery cooperative members, Bench Maji Zone Livestock and Fishery Office, development agents and experts who assisted and cooperated very positively for this study a success.

The authors have not declared any conflict of interests.