Diversity of Fish in the River

The Rapti River originates in the Mahabharat Range in Central Nepal and flows east to west through the inner Terai region, passing through the Chitwan Valley. It harbors to diverse wildlife, different fish species and other aquatic animals. The study aimed to explore baseline information on the diversity and abundance of fish species and their relationship with environmental variables. A study was carried out to understand the diversity of fish in Rapti River at three different stations. A total of 25 species of fishes belonging to 6 orders, 12 families and 18 genera were recorded. Among the orders, Cypriniformes had the highest number of species (52%) followed by Siluriformes (24%), Perciformes (12%) while Tetraodontiformes, Synbranchiformes, Beloniformes represented each about by 4%. Fish conservation in Rapti River was very effective because only license holder fisherman can catch the fish in river. Local fisherman believed that traditional medicinal benefits of fish species like Puntius ticto supports to increased milk production during breast feeding and some fish species like Glyptothorax telchitta, Puntius ticto and Garua bachcha were declining day by day due to various anthropogenic activities like pollution, regular fishing, illegal fishing and so on.

Fishing is a vital resource for many developing countries, offering economic benefits and employment. In Ethiopia, aquaculture holds potential for improving food security and alleviating poverty, though it remains underdeveloped. Fish is a key part of the national nutrition strategy, providing essential nutrients like vitamins, minerals, and protein. However, traditional fishing methods, outdated equipment, illegal fishing, overfishing, and fish diseases hinder the sector's growth. The government is strengthening regulations to address these challenges and promote sustainable resource management. Postgraduate programs in fisheries and aquaculture aim to build expertise in the sector. To ensure long-term sustainability, efforts should focus on raising awareness, fostering local investment, and advancing research in fish production and lake management.

Fishing is an important and renewable natural resource base for many developing countries, providing jobs, hard currency, and government revenue. Aquaculture is an alternative method of achieving food security and poverty reduction in Ethiopia, but its status is less developed. Fish is an important food for Ethiopia's national nutrition strategy, as it is high in vitamin B12, calcium, iron, zinc, fatty acids, and animal protein. Fish meat is comparable to that of cattle, pig, lamb  sheep, and poultry, and provides an excellent source of protein for human diet. The fisheries sector in Ethiopia is a good way to create job opportunities for rural, pre-urban, and urban unemployed and under-employed people. Recreational fishing has been popular in Ethiopia since the 1970s, with the introduction of two species of fish, Brown trout and Rainbow trout, from Kenya to the rivers of the Bale National Park. Traditional fishing methods and equipment are to blame for the low level of fish output and productivity. Governments are tightening controls on fishing vessels, activities, fish transit, and fish trade to combat illicit fishing and better manage their fishery resources. Overfishing is a major issue in Ethiopia, threatening the sustainability of the fisheries resource. Fish diseases are also a problem, reducing fish production and leading to mass mortalities. Fishery management is an integrated process of information gathering, analysis, planning, decision-making, resource allocation, and formulation and enforcement of fishery regulations. Postgraduate programs in fisheries and aquaculture are available at universities and technical institutions. To preserve and improve the advantages of the catch fishery, organizations should encourage awareness of fish welfare and productivity, identify and control threats, encourage indigenous investors to invest in scientifically supported and technologically advanced aquaculture, and conduct further studies on fish production and lake fishery management.

Although wetlands in Ethiopia provide multiple ecosystem services, they are extremely affected because of human pressure and limited policy attention. We aimed this study at analyzing the ecological services and drivers of the degradation of the Abaya-Chamo lake-wetland. We gathered data using a questionnaire survey of 304 HH (selected via systematic sampling), interviews, and satellite images. Normalized difference vegetation, water, and turbidity indices were used for satellite image interpretation via ArcGIS. Mean, standard deviation, correlation, and regression were used for data analyses. Abaya-Chamo lake-wetland offers fish, timber, firewood, fodder, irrigation, farmland, rainfall, habitat, tourism, aesthetics, recreation, carbon sink, air quality, and climate control services. The area showed siltation-led raising turbidity and a loss of 48.9% of its swamp area from 1990 to 2019. Farm expansion, siltation, irrigation, invasive plants, open access and overuse of resources, lac...

Although wetlands in Ethiopia provide multiple ecosystem services, they are extremely affected because of human pressure and limited policy attention. We aimed this study at analyzing the ecological services and drivers of the degradation of the Abaya-Chamo lake-wetland. We gathered data using a questionnaire survey of 304 HH (selected via systematic sampling), interviews, and satellite images. Normalized difference vegetation, water, and turbidity indices were used for satellite image interpretation via ArcGIS. Mean, standard deviation, correlation, and regression were used for data analyses. Abaya-Chamo lake-wetland offers fish, timber, firewood, fodder, irrigation, farmland, rainfall, habitat, tourism, aesthetics, recreation, carbon sink, air quality, and climate control services. The area showed siltation-led raising turbidity and a loss of 48.9% of its swamp area from 1990 to 2019. Farm expansion, siltation, irrigation, invasive plants, open access and overuse of resources, lack of legal framework, and rapid population growth were the main drivers of wetland degradation. Land degradation is anticipated adjacent to the lake-wetland in the next few decades because of irrigation. Invasive plants result in dwindling aquatic resources, economic, and tour benefits, and changes in local climate depleting water, and the dissolved O2 and CO2 sink capacity of the lake-wetland rapidly. Thus, the government should plan a clear policy and legal framework for the sustainable management of wetlands.

Africa's greatest population of livestock is found in Ethiopia. Over 51,500 tons of fish may be produced annually by the livestock industry, which also contributes over 49% of the agricultural GDP and 80% of all jobs. The purpose of this paper is to examine Ethiopia's present level of fish production. and to examine Ethiopia's present consumption patterns Ethiopia's system of producing fish is founded on the idea of unrestricted access to resources, which are defined by a variety of fishing gear. Gillnets, beach seines, long lines, hook-and-line, and cast nets are examples of fishing gear technology that is frequently used in Ethiopian fisheries. Fish is one of the recognized aquatic species used as food by humans, and its consumption is on the rise. The protein content of aquatic animals ranges from 17 to 29%, and their amino acid profile is comparable to that of land animal flesh. Fisheries are severely hampered by the fact that main pollutants affecting Ethiopian water bodies and their fish are said to originate from the sewage of factories and agriculture. Fish production is impacted by the textile and mineral extraction sectors.

Fish has historically played an important role in food security in many countries and contributes to do so in globally, providing 15-20 percent of animal protein intake. Fishery has been practiced in different parts of the world. At present, the country Ethiopia has an estimated annual total exploitable fish potential of 51,481 tons, which can meet only 79 percent of the current actual demand, 55 percent of the projected demand in 2010 and 44 percent of the projected demand in 2015, based solely on population size. Ethiopia contains many lakes and rivers for fish production and also different species of fishes exist in these lakes and rivers. In addition to this there is good environmental condition for fishery and there is huge agricultural and Industrial by Product or residue due to the country mostly based on agriculture and also few industry to sustain the life of the people. Using of these opportunities fishery is an alternative means achieving food security and poverty reduction in Ethiopia. In spite of these opportunities, fishery sector of the economy has various problems, among others climate change, mismanagement of the resource, inappropriate policies and institution, inadequate technical and material backup to the sector and market are the major ones. The objective of this paper is to review the opportunities and challenges of fisheries in Ethiopia. Due to these challenges fishery is still an infant which means cannot fill the need of the demand. Therefore, the government and private should take consideration for fishery sub sector to increase productivity and gross domestic product of the country by alleviating these challenges.

Six sampling sites of Gilgel Abay River and its tributaries, were sampled by using monofilaments (5-55 mm) and gillnets having mesh sizes of 6, 8, 10, 12 and 14 cm stretched bar mesh with a length of 25 m and depth of 1.5 m, twice each month from August to October, and once in November, 2011. Fishes were identified to the species level. Fork length (FL), total weight (TW) and gonad weight (GW) of each specimen were measured. The relationship between FL and TW for the dominant species of Labeobarbus showed curvilinear relationship. Condition factor of L. intermedius, L. brevicephalus and L. nedgia showed that there was significant difference (p<0.001) between sexes in all three species. In all catch, females were more numerous than males. The highest GSI (15.54%) was recorded for L. brevicephalus but the maximum mean monthly GSI (7.01%) was recorded for L. longissimus in September and minimum GSI (0.45%) for L. macrophtalmus in August. Absolute fecundity, mean fecundity and mean FL for L. intermedius was the highest than the rest. The relationship between absolute fecundity (AF) and FL, TW, and GW of L. intermedius, L. brevicephalus, and L. nedgia were linear (AF=596.4FL-8990, R 2 =0.79; AF=19.78TW+978.1, R 2 =0.79 and AF=371.5 GW+573.5, R 2 =0.93). There was also strong relationship between AF and FL, TW, and GW (p<0.001) in the three species.

In the present paper, an attempt is made to investigate whether the body shape indices can be used to predict food habits of fish species in three reservoir fish communities of Sri Lanka. The present analysis is based on the studies on food and feeding habits of fish species and their body shape indices in three Sri Lankan reservoirs, namely Minneriya, Udawalawe and Victoria. Body proportions of individual fish species were determined as P1 (= Maximum height of the body/ Maximum width of the body) and P2 (= Total length/ Maximum height of the body), which were found to be negative curvilinearly related. Trophic indices (Ti) of individual fish species were determined on the basis of trophic level of each food item and the fractions of all food items consumed by fish species, which ranged from 1 for exclusively herbivorous species to 3 for carnivorous species. A negative logarithmic relationship between P1 and Ti indicates that laterally compressed fish species with deep bodies feed o...

Now-a-days changes in land use system to meet the demands of a growing global population are inducing a shift in the socioeconomic and ecological functions of wetlands. The objective of this study was therefore to assess the level of community’s perception on wetland conservation as well as to determine the trends/changes in status of wetlands in Lake Ziway shore area in the previous years and compare them to the present situation. A short survey was undertaken to identify and investigate the community perceptions on wetland degradation. Data was collected from purposefully selected group through questionnaire survey, focused group discussions (open ended guide questions for purposefully selected community members), and also personal field observations. The view of the respondents from the survey has indicated that the high conversion and loss of wetlands over time in the area due to population growth leading to farm land scarcity, over-grazing, sedimentation, direct conversion in t...

Present study was carried out to assess the abundance and diversity of fin-fish and prawn species in the selected five reservoirs in the Northern Province, Sri Lanka. Fin-fish and prawns caught by multi-mesh gillnets, and rod and hooks, were sampled from January to December 2017. Relative abundance and diversity indices were calculated and, differences and similarities among reservoirs in different months were assessed. The hierarchical clustering was used in constructing dendrogram. Of the 27 finfish species and two freshwater prawn species identified in total, the highest number of species were observed in Muthayankattu reservoir (26 species) while Puthumurippu reservoir had the lowest (14 species). Oreochromis niloticus was the dominant species in all the reservoirs. Small reservoirs (Puthumurippu, Kalmadu and Muhathankulam) showed high Shannon-Weiner diversity index and evenness, though low in dominance index, compared to large reservoirs (Vavunikulam and Muthayankattu). Selective harvest methods, number of fishers and seasonal variation of hydro-climatic factors such as rainfall, strong wind and water level significantly influenced the diversity of fish species. Increasing fishing pressure and use of destructive fishing methods during low water level were the main contributors for diversity loss in the five perennial reservoirs studied.

Diversity, relative abundance and some biological aspects of fishes in Geba and Sor Rivers were studied using gill nets (6, 8, 10 and 12cm stretched mesh sizes) and hooks. Samples of fish were collected in wet (October to November 2012) and dry (February to March 2013) seasons. A total of 348 fish specimens were collected from both rivers at both seasons. Nine fish species were identified which were included in six genera and four families. The represented families include Mormyridae, Cyprinidae, Bagridae and Cichlidae. The family Cyprinidae was the most dominant with respect to number of species consisting of six species (66.7%). The diversity of fish species in Geba River (H&#39;=1.50) was higher than that of Sor River (H&#39; =1.10). The fish diversity of Geba and Sor Rivers is less compared to most studied Ethiopian rivers. Labeobarbus intermedius (60.72%IRI), Labeobarbus nedgia (16.83%IRI) and Labeo cylindricus (14.66%IRI) were the most abundant fish species. The abundance of f...

The study was conducted in 2011 at four sites of Infranz River selected based on the nature, velocity of the flowing river, human interference and, suitability for fish spawning. Fish samples were collected using gill nets of 6, 8, 10 and 14 cm and monofilament having 5-55 mm mesh size. The potential Evapotranspiration of the river was estimated using the Thornthwaite method. Flow rate of the river was simulated from precipitation data using a 3- parameter monthly water balance model. The CV value for the mean monthly flow (CV= 0.96) was much larger than that of the annual flow (CV=0.19). The river showed an overall decreasing trend of flow rate. The number of adult fishes captured in the river was directly related to the flow. The number of Juveniles was less during the high flow seasons. The number of male and female was positively correlated with flow rate of the river. The decreased in river flow rate have an effect on migratory species; hence, management activities should be pr...

In Ethiopia, particularly in Tana Sub-Basin, irrigation development practice is increasing. However, this development ignored the fisheries; no, enough information about its effects. The sub-basin is rich in fisheries, including the 17 Labeobarbus species (the only remaining cyprinid species in the world). The fishery is also supporting over 6000 fishers. Hence, this study investigated the impact of irrigation practices on the Gilgel Abay, Ribb, and Gumara fisheries. Methods include fish sampling below and above the weirs, expert interviews, key informant interviews, secondary data, and impact significance matrix methods. The data collection time was from July 2019 to June 2020. The analysis of the data was qualitative and quantitative. The existing irrigation system affects fisheries by blocking upstream spawning migration routes (Gilgel Abay Weir and Ribb Dam, for sure catch below the Gilgel Abay Weir, significantly higher than above the weir, Shannon Index (H'), P < 0.001). Besides, according to local sources, after 2007, Gumara and Ribb Rivers became seasonal because of excessive water abstraction for irrigation, resulting in mass fish-killing and the failure of juvenile recruitment to the lake. In one instance, we recorded the deaths of over 930 adults and juveniles on the Gumara and the Ribb Rivers. Succeeding low water volume, even non-fishers collect fish from the pools; and during spawning time, fishers target spawning migratory species at the weirs where the catch is prime is also the other problem. Other threatening elements can also aggravate the impact. Hence, these impacts need to be ameliorated by practicing efficacious water use, catchment treatment, fishery management, fish ladder development, and factor alleviation can be solutions.

The wetland ecosystem is among the most important ecosystems globally. It is a source of ecosystem services that can contribute to the income and means of livelihood for communities living near the vicinity of wetlands especially in developing countries. Ethiopia is among the least developing countries in Africa where many communities around the wetlands depend on ecosystem services for their livelihoods. However, these wetlands are being degraded both by anthropogenic and natural factors. The objectives of the study were to assess the status of the major wetlands and their contribution to the livelihoods of communities in South Wollo Zone of Amhara Regional State located in North-Eastern Ethiopia. Districts in South Wollo with wetland potential were selected purposely in collaboration with Zonal Agricultural Office experts. A multistage sampling technique was used to select 114 respondents living around the wetlands for the interview. In addition to this, three focus group discussi...

The wetland ecosystem is among the most important ecosystems globally. It is a source of ecosystem services that can contribute to the income and means of livelihood for communities living near the vicinity of wetlands especially in developing countries. Ethiopia is among the least developing countries in Africa where many communities around the wetlands depend on ecosystem services for their livelihoods. However, these wetlands are being degraded both by anthropogenic and natural factors. The objectives of the study were to assess the status of the major wetlands and their contribution to the livelihoods of communities in South Wollo Zone of Amhara Regional State located in North-Eastern Ethiopia. Districts in South Wollo with wetland potential were selected purposely in collaboration with Zonal Agricultural Office experts. A multistage sampling technique was used to select 114 respondents living around the wetlands for the interview. In addition to this, three focus group discussi...

We compared the food webs of three Sri Lankan reservoirs: Minneriya (ancient and shallow; Udawalawe (young and shallow) and Victoria (young and deep). Species richness of the fish community was highest in Minneriya (30 species), intermediate in Udawalawe (21 species) and lowest in Victoria (18 species). Fish species belonged to 11 families, with Cyprinidae dominating the community both in terms of abundance and species richness. We used the daily amount of food consumed per fish species to distinguish weak from strong trophic interactions in these food webs. The fish community consumption pattern was characterized by a few strong interactions and many weak ones. The number of major consumers (contributing > 5% of the total fish community consumption) in each reservoir was small and similar for the three reservoirs. Puntius filamentosus 1 and Amblypharyngodon melettinus were the two major consumers in all three food webs. Puntius chola was a major consumer in Minneriya and Victoria, but not in Udawalawe, where it was feeding less on detritus than in the other two food webs. In all three reservoirs was the fish community mainly feeding at the bottom of the food web, on algae, macrophytes and detritus, with very little piscivory taking place. Average food web length was measured as the mean trophic index weighted for the consumption rates of the various fish populations which together compose the fish community. In comparison with most other tropical lake/reservoir food webs in Asia and Africa, of which data were available, was the average food web length in the Sri Lankan reservoirs relatively short. Furthermore, traditionally unexploited species, as opposed to species of commercial fisheries interest, Oreochromis mossambicus and O. niloticus, are major role players in trophic dynamics of reservoir ecosystems. As such, the potential of their exploitations should be considered in the management of reservoir fisheries.

Present study was mainly investigated length-weight relationships and condition factor of M. rosenbergii stocked in two large (Vavunikulam, Muthayankattu) and three small (Puthumurippu, Kalmadu, Muhathankulam) perennial reservoirs in Northern Province of Sri Lanka as culture-based fisheries. Randomly selected 300 Macrobrachium rosenbergii caught by multi mesh gillnets between January to December 2017 were analyzed. Non-linear regression analysis was conducted for total length (L) and body weight (W) of M. rosenbergii as power function W= aLb. Fulton’s condition factor (K) was calculated by using the formula: K = (W * 100)/L3. One-way ANOVA and Tukey comparison was conducted for significance of condition factor among reservoirs. Allometric growth coefficient (b) ranged between 2.1295 – 4.2068. Highest b value was observed in both Kalmadu (b=4.2068) and Puthumurippu (b=4.1132), while the lowest from Vavunikulam (b=2.1295). Mean condition factor (K value) of M. rosenbergii ranged from ...

Wetlands are important environmental resources for rural livelihoods in Ethiopia. The study investigated spatiotemporal change of wetlands, drivers and effects in North Central Ethiopian Highlands. Landsat satellite imageries of 1984, 1993, 2000, and 2013 were used to analyse wetland changes over the last three decades. Practical observations, interviews and discussions with local communities and officers were also conducted to address the main objective. Furthermore, secondary data on crop yields were collected to supplement the primary data. The study shows that wetlands have been converted into built-up areas and farmlands. Wetlands in the study area experienced annual loss across the entire study period. Consequently, the area size of wetlands decreased from 7.4 per cent in 1984 to 2.6 per cent in 2013. About 66 per cent of the total wetlands was lost within 30 years mainly due to farmland encroachment and urban expansions. The highest rate of wetland change was recorded between 2000 and 2013. Such wetland changes increased conflicts among land users. However, the converted wetlands increased short-term benefits due to wetland recession agriculture. To conclude, wetland resources are under enormous threats, and challenge the sustainability of livelihoods. Thus, integrated and adaptive wetland restoration policies could improve the degraded wetlands.

This paper reviews the major existing and potential threats of Ethiopian fishery and there possible mitigation. Ethiopia has a rich diversity of Ichthyo-fauna in its lakes, rivers and reservoirs, although they are poorly known. Seven major threats to lakes of the world include: accelerated Eutrophication, invasive species, toxic contamination, overfishing, water diversion, acidification, and climate change. However in Ethiopia there are a number of challenges which affect fishery such as overfishing, wetland degradation, Dam construction for the purpose of hydropower and irrigation, deforestation and Urbanization and industrialization. The possible mitigation of the above problems has management strategies should comprise both biophysical and socioeconomic aspects with emphasis on issues like adoption of watershed/ecosystem approach at policy level, integration of income generation in conservation activities, sharing of responsibility/benefits among local stakeholders, institutional strengthening for environmentally and socioeconomically sustainable development of lakes. To protect the major challenges of fresh water are watershed protection include: reducing pollution by silt load, preventing negative water level fluctuation, eliminating overexploitation of resources, mitigation of conflict of interest in the use of water and land resources (deforestation, water logging, flooding, overgrazing, population pressure, and degradation).

Nowadays, depletion of ecosystems and their services is a vital problem especially in developing countries like Ethiopia where the peoples&#39; livelihood is highly linked with the direct exploitation of ecosystem goods and services. The objective of this study was to analyze LU/LC dynamics, its drivers, the benefits, and challenges of the wetland ecosystem of Abaya. Data required for this study were acquired from satellite images and also through administration of questionnaire on134 sample households, interview, and FGD at Chano Keble&#39;s. Satellite image of the study area for periods 1986, 2000 and 2010 were analyzed via ERDAS 3.6 and also change detections were made within 1986 – 2000 and 2000 - 2010. The result showed that, uniquely, while forest cover revealed an increasing trend in period (1986 – 2000about 36.99%and 2000 - 2010about3.70%), while cultivated land and settlement experienced declining trendby the respective proportions of – 1.87%and- 59.63% within1986 – 2000 pe...

Nowadays worldwide projected growth of population pressure with a steadily growth of disposable income and urbanization corroborated by global markets corridor are expected to elicit a substantial increase the demands of high value foods. These situation causes to exploit the aquatic ecosystems mainly for fish, the largest single source of animal protein and fastest growing food commodity. Likewise, Ethiopia has enormous potential of freshwater (126.5 BMC) available per year; plus favorable environments considered to be significant scope for fisheries development for fish yield (about 94,509 ton/year + 5.3% as 73,104 ton/year + 3.3% for lentic and 2,1405 ton/year +11.8% for lotic ecosystems). Ethiopian water resources deduced to hold over 180 fish species, freshwater shrimps, crabs, mollusks, commercially important microalgae, and vegetation. However, currently actual fish yield is (about 51,581 ton/year) much far below expected level, which resulted in lower per capita consumption ...

The giant freshwater prawn (Macrobrachium rosenbergii), was first introduced to the reservoirs in the Northern Province of Sri Lanka. Studies on the performances of introduced species in reservoirs are essential for development of fisheries and management. The objective of the present study was to evaluate and compare the performance of M. rosenbergii production in five selected perennial reservoirs. Primary data relating to the fisheries of the reservoirs and relevant socioeconomic data were gathered through field data collection and questionnaire survey conducted in 2016 and 2017. Unit production of M. rosenbergii in 2017 in the Vavunikulam, Muthayankattu, Puthumurippu, Kalmadu and Muhathankulam reservoirs was 5.3 kg/ha, 3.2 kg/ha, 13.6 kg/ha, 21.8 kg/ha, 12.9 kg/ha, respectively with a farm-gate values of 6.84, 4.39, 2.1, 1.59, and 2.85 million Sri Lankan rupees, respectively. Relative abundance, economic (total farm-gate price) contribution and recapture rate of M. rosenbergii in the catch, ranged between 2.3%-20%, 13.5%-72.3% and 1.44%-6.49%, respectively across the reservoirs. Even though the recapture rate was low, catching of M. rosenbergii improved the livelihood of fishers while increasing their interest in fisheries. Size of the reservoir, stocking density, fishing intensity and gear specification, rainfall, wind and socioeconomic factors significantly influenced the catch of M. rosenbergii in the selected reservoirs. The results showed that the introduction of M. rosenbergii as culturebased fisheries in the selected five reservoirs has achieved considerable success, particularly in terms of economic benefits.

Morphometric relationships of African big barb, Labeobarbus intermedius (Rüppell, 1836) (Pisces: Cyprinidae) in Lake Koka, Ethiopia was studied based on the total number of 266 adult fish samples collected in April-May and July-August 2011. Fish ranging from 23.3 to 49.0 cm in total length (35±4.1 cm) and from 95.4 to 1200 g in total weight (434.4±206.5 g) were randomly sampled. Of these, 55.6% (n=148) were males and 44.4% (n=118) were females. The length-weight relationship of the males, females and combined fish were curvilinear and statistically significant (P< 0.01). L. intermedius in Lake Koka has positive allometric growth pattern, which was statistically significant (p< 0.01). Females were more allometric in their growth pattern, but statistically not significant (P>0.01). Length-length relationships between total length (TL) and fork length (FL), fork length (FL) and standard length (SL), TL and SL were linear and statistically significant (P<0.01). Result of Fulton condition factor showed no significant differences between males and females (P>0.01). The overall condition factor for all sampling period was 1.0.

Abstract: Wetlands provide flood and erosion control, providing economic and social benefits to communities living around the wetlands (Yilma Delelegn and Geheb, 2003). Although wetlands have many known characteristics that are important to the livelihoods of local inhabitants, they are degraded and lost due to a lot of triggering factors. Similar to other wetlands in the country, Tekuma wetland has been affected by different factors. Wetlands and their value remain little understood and their loss is increasingly becoming an environmental disaster (Yilma Delelegn and Geheb, 2003). Thus, a study was conducted in Tekuma wetland, south western part of Lake Tana in Ethiopia to investigate the impacts of the loss of wetland on socioeconomic values. In order to select the research site and respondents, purposive and simple random sampling techniques were applied. Socioeconomic data, collected using structured questionnaire, were analyzed using descriptive statistics, paired and one sampl...

Wetlands provide flood and erosion control, providing economic and social benefits to communities living around the wetlands (Yilma Delelegn and Geheb, 2003). Although wetlands have many known characteristics that are important to the livelihoods of local inhabitants, they are degraded and lost due to a lot of triggering factors. Similar to other wetlands in the country, Tekuma wetland has been affected by different factors. Wetlands and their value remain little understood and their loss is increasingly becoming an environmental disaster (Yilma Delelegn and Geheb, 2003). Thus, a study was conducted in Tekuma wetland, south western part of Lake Tana in Ethiopia to investigate the impacts of the loss of wetland on socioeconomic values. In order to select the research site and respondents, purposive and simple random sampling techniques were applied. Socioeconomic data, collected using structured questionnaire, were analyzed using descriptive statistics, paired and one sample t-test t...

The reproductive biology of dominant fish species below the Tisisat Fall of Blue Nile River was studied during the wet season (September-October, 2010) and dry season (March-April, 2011) using gillnets of stretched mesh size 6, 8, 10 and 12cm, monofilaments of different mesh size, castanet and hook and line. A biotic parameters, temperature, transparency, conductivity, pH and total dissolved solid of the river were taken. A total of 857 fish specimens were collected with the two sampling seasons from all sampling sites. Out of the total catch of specimens four dominant fish species was contributed 79 %. The length weight relationship of L. intermedius, L. forskalii and M. kannume were curvilinear and the relation was statistically significant (P 0.05) in both season and sex however, L. forskalii was statically significant (P&lt; 0.01) in seasons only. Except L. nedgia M. kannume, C. gariepinus and O. niloticus species were collected from the Blue Nile river were significant differen...

Lake Ziway is the most exploited lake for fishery, irrigation, recreation and tourism, the fishery sustainability of which is reported under threat because of the overfishing activity resulting from an increasing number of fishers residing around the lake. The main concern of this study was, therefore, to analyze the major socioeconomic and institutional factors that determine people's decision to be engaged in fishing activities there by contributing to the over utilization of the fish resource in Lake Ziway. The study was based on the data obtained from randomly selected 120 households in four Peasant Associations (PAs) purposely selected from two districts. Binary logistic regression analysis was used to identify socioeconomic and institutional factors that determine the utilization of fish resource in the lake. Eight explanatory variables were included in the model out of which five were found to be significant. Results of the logistic regression analysis indicated that age, educational level, distance of household's home from the lake and other income generating activities determine fish resource utilization negatively while credit access was found to have a positive impact. In the analysis of the relative importance of the significant variables it was found that a one year increase in the age of an average household will decrease the probability of his engagement in fishing activities by 1.6% and a 1 km increase in the distance of the household's residence from the lake to decrease the probability of engagement in fishing activity by 8.7%. Furthermore, the probability of being fisherman increases for a person with the education level of reading and writing by 30.4% as compared to a household with a higher education while the probability for a household who does not have other source of income increases by 42%; and it increases for the one who has credit access by 26%. The finding of the study suggests that, improving the educational level and facilitating diversified income generating opportunities for the households living around the lake would help to mitigate the overutilization.

As it has been reported that there is a harvestable potential of presently unex-ploited small cyprinid species in Sri Lankan reservoirs, attempts were made to investigate the gillnet selectivity for small cyprinids in three reservoirs with a view to defining regula-tory measures for the subsidiary gillnet fishery. As exotic cichlids support profitable fisheries in reservoirs of Sri Lanka, any strategy to exploit small cyprinids should not adversely affect the cichlid stocks. Possibly due to the depth preference, exotic cichlids are not caught in small mesh (12.5 to 37 mm) gillnets which are set in the areas with water depths of over 2 m. The effective mesh sizes (stretched) of gillnet which were set in these areas were 16 and 20 mm for Amblypharyngodon melettinus and 33 and 37 mm for Puntius chola and P. filamentosus. Although P. dorsalis is caught in significant numbers in 50 and 60 mm mesh gillnets, this species is unlikely to be exploited without harming exotic cichlids because s...

Oreochromis niloticus (Linnaeus, 1758) exhibits differences in demographic parameters across the reservoirs, resulting in inconsistencies in optimal fishing strategies. This study aimed at investigating O. niloticus populations in 10 reservoirs. Length-frequency data of O. niloticus from fish landings of 10 irrigation reservoirs in Sri Lanka were corrected for multi-mesh gillnet selection and were analysed by FiSAT II stock assessment software. Asymptotic total length ranged from 42.8 cm to 53.4 cm and growth constant ranged from 0.20 yr-1 to 0.49 yr-1. As growth performance indices of 10 reservoir populations of O. niloticus were within the range reported previously and as the estimated growth parameters fall within the “growth space” of the species, these estimates were consistent with those reported in the literature. Length-converted catch curves of 10 reservoir populations of O. niloticus also gave reliable estimates of total mortality. Exploitation rates of the 10 populations ...

As it has been reported that there is a harvestable potential of presently unexploited small cyprinid species in Sri Lankan reservoirs, attempts were made to investigate the gillnet selectivity for small cyprinids in three reservoirs with a view to defining regulatory measures for the subsidiary gillnet fishery. As exotic cichlids support profitable fisheries in reservoirs of Sri Lanka, any strategy to exploit small cyprinids should not adversely affect the cichlid stocks. Possibly due to the depth preference, exotic cichlids are not caught in small mesh (12.5 to 37 mm) gillnets which are set in the areas with water depths of over 2 m. The effective mesh sizes (stretched) of gillnet which were set in these areas were 16 and 20 mm for Amblypharyngodon melettinus and 33 and 37 mm for Puntius chola and P. filamentosus. Although P. dorsalis is caught in significant numbers in 50 and 60 mm mesh gillnets, this species is unlikely to be exploited without harming exotic cichlids because sub...

The effect of long-term use on the catch efficiency of biodegradable gillnets was investigated during commercial fishing trials and in controlled lab aging tests. The relative catch efficiency between biodegradable and nylon gillnets was evaluated over three consecutive fishing seasons for Atlantic cod (Gadus morhua) in Norway. The biodegradable gillnets progressively lost catch efficiency over time, as they caught 18.4%, 40.2%, and 47.4% fewer fish than the nylon gillnets during the first, second, and third season, respectively. A 1000-hour aging test revealed that both materials began to degrade after just 200 h and that biodegradable gillnets degraded faster than the nylon gillnets. Infrared spectroscopy revealed that the chemical structure of the biodegradable polymer changed more than the nylon. Although less catch efficient than nylon gillnets, biodegradable gillnets have great potential for reducing both capture in lost fishing gear and plastic pollution at sea, which are maj...

The effect of long-term use on the catch efficiency of biodegradable gillnets was investigated during commercial fishing trials and in controlled lab aging tests. The relative catch efficiency between biodegradable and nylon gillnets was evaluated over three consecutive fishing seasons for Atlantic cod (Gadus morhua) in Norway. The biodegradable gillnets progressively lost catch efficiency over time, as they caught 18.4%, 40.2%, and 47.4% fewer fish than the nylon gillnets during the first, second, and third season, respectively. A 1000-hour aging test revealed that both materials began to degrade after just 200 h and that biodegradable gillnets degraded faster than the nylon gillnets. Infrared spectroscopy revealed that the chemical structure of the biodegradable polymer changed more than the nylon. Although less catch efficient than nylon gillnets, biodegradable gillnets have great potential for reducing both capture in lost fishing gear and plastic pollution at sea, which are maj...

Fish fauna of Pakistan has been observed by large number of researcher at wide range; present data collected at specific two sites, Head Qadirabad and Head Khanki at River Chenab, and also observed the threats to Carps fish and its ecology in successive three years (2007-09). In this data observed that the population of carps was decreased gradually and also identified the threats to fish fauna of river Chenab. Shannon- Weiner Diversity Index (H&#39;) of Carps fish in Head Qadirabad were observed 1.396 in 2007; 1.36 in 2008 and 1.136 in 2009, while Evenness (E) were 1.396 in 2007; 1.36 in 2008 and 1.136 in 2009 and Richness were 2.943 in 2007; 3.042 in 2008 and 3.188 in 2009 and Shannon- wiener diversity of Head Khanki were 1.328 in 2007; 1.123 in 2008 and 1.094 in 2009 while Evenness (E) were 0.741 in 2007; 0.63 in 2008 and 0.611 in 2009 and Richness were 2.8601 in 2007; 3.0244 in 2008 and 3.080 in 2009.

The study investigates aspects of the fresh water fish resource potential estimation by considering Lake Ardibo, a Crater Lake in the northern highland of Ethiopia. The general aim of this study was to produce a scientific guidance paper on the estimation of fish resource potential of Lake Ardibo and to show the practical applicability of the different fish resource potential estimations models in Lake Ardibo. And this research was done by taking seasonal data from the selected three sampling sites i.e. some limnological parameters (physico-chemical parameters) in the period from February 2009 till January 2010. The sampling sites were located the first one near the shore (littoral site-SS1), the other the vegetated-SS2, one with a relatively dense macrophyte vegetation and the 3rd site was pelagic-SS3. The locations of the sites were identified by the Global Positioning System (GPS). And also series year of catch effort data were collected from Woreda livestock and fishery office and fishery cooperatives. Based on the collected data analysis were made using empirical and Schaefer production models. Hence the empirical models estimation shows 98.1 kg per hectare per year or 206 tons per year; whereas the Schaefer production model gives maximum sustainable yield (MSY) of 3452.5 kg per hectare per year or 3.45 tons per hectare which means 7250 tons per year from the lake and f MSY is 416 standard boats. Results of the Schaefer-Fox model were higher than the empirical estimates. Thus, the Lake can provide sustainable a production of fish, i.e., MSY on average 98.1 kg/ha per year or 206 tons per year from empirically found relationships.

This paper reviews the major existing and potential threats of Ethiopian fishery and there possible mitigation. Ethiopia has a rich diversity of Ichthyo-fauna in its lakes, rivers and reservoirs, although they are poorly known. Seven major threats to lakes of the world include: accelerated Eutrophication, invasive species, toxic contamination, overfishing, water diversion, acidification, and climate change. However in Ethiopia there are a number of challenges which affect fishery such as overfishing, wetland degradation, Dam construction for the purpose of hydropower and irrigation, deforestation and Urbanization and industrialization. The possible mitigation of the above problems has management strategies should comprise both biophysical and socioeconomic aspects with emphasis on issues like adoption of watershed/ecosystem approach at policy level, integration of income generation in conservation activities, sharing of responsibility/benefits among local stakeholders, institutional strengthening for environmentally and socioeconomically sustainable development of lakes. To protect the major challenges of fresh water are watershed protection include: reducing pollution by silt load, preventing negative water level fluctuation, eliminating overexploitation of resources, mitigation of conflict of interest in the use of water and land resources (deforestation, water logging, flooding, overgrazing, population pressure, and degradation).

Nowadays worldwide projected growth of population pressure with a steadily growth of disposable income and urbanization corroborated by global markets corridor are expected to elicit a substantial increase the demands of high value foods. These situation causes to exploit the aquatic ecosystems mainly for fish, the largest single source of animal protein and fastest growing food commodity. Likewise, Ethiopia has enormous potential of freshwater (126.5 BMC) available per year; plus favorable environments considered to be significant scope for fisheries development for fish yield (about 94,509 ton/year + 5.3% as 73,104 ton/year + 3.3% for lentic and 2,1405 ton/year +11.8% for lotic ecosystems). Ethiopian water resources deduced to hold over 180 fish species, freshwater shrimps, crabs, mollusks, commercially important microalgae, and vegetation. However, currently actual fish yield is (about 51,581 ton/year) much far below expected level, which resulted in lower per capita consumption of fish per year (0.216 kg) compared to other African countries. This is attributed to several constraints in which, traditional methods of fish farming and fishing, limited awareness, management skills, skills and technological knowhow; besides the impacts of climate change and global warming, ecosystems degradation, mismanagement, siltation, growing toxic weeds in most lakes, with marked overfishing practices by fishermen are the dominant challenges. To reverse these scenarios into the desired track, urgent intellectual measures should be at hand in Ethiopia. Therefore, this article was studied through the collected 19 years' published and unpublished source materials, data analyzed and empirical models were applied to explore updated fundamental information on current potential of fisheries resources and overall status of aquaculture development, so as to create better understanding, and to suggest scientific strategies and better approaches for the sector contribute in the sources food, employment, and livelihood in Ethiopia. Finally, this paper is recommended to be beneficial to the readers and policy makers for the fisheries and aquaculture development in Ethiopia and the region.

All animals or plants that are introduced intentionally or inadvertently do not successfully colonize in the new environment. This is particularly due to lack of the perfect niche. According to the available records, about 20 out of the 25 fish species introduced to Sri Lanka's fresh waters have successfully invaded the native habitats. Less than 10 species have not been able to maintain their populations' naturally in Sri Lanka. There is a scarcity of information on the ecological impact of introduced fish species on the local fish fauna, ecosystem functions and goods and services provided. This paper attempts to predict invasiveness of introduced fish species by identifying their body shapes and ecology, which is an eco-morphological approach. Body morphology of fish can be measured using various methods as vertical and horizontal distances. Location of body organs, their shapes and the orientation or the direction from the center of the body can be considered as mensural measurements. Height, length and width of the body indicate important aspects of the ecology of fish. Proportions of the height, length and width are important parameters to show the ecomorphology of fish. Gross Body shapes that can be defined as P 1 (Height of the body/Width of the body) and P 2 (Total length/ Height of the body) are known to be useful parameters to predict the niche of the fish, particularly food habits and the ecology. The present analysis is based on the P 1 and P 2 values obtained from about 35 Sri Lankan freshwater fish species. According to the P 1 and P 2 values, the native carnivorous freshwater fish in Sri Lanka have dorso-ventrally flattened slender, long-bodies (low P 1 and higher P 2) whereas the herbivores have short, deep bodies (high P 1 and low P 2). Chitala ornata (family; Notopteridae) is an accidentally introduced exotic fish and has a short and deep body (high P 2 and low P 1). According to the gross body morphology, C. ornata would share a niche that would belong to native herbivore, and segregate niche with native carnivores. In two ecological dimensions C. ornata is showing its positive invasiveness with less competition. Chitala ornata is a voracious piscivorous fish representing an outlier in the P 1 and P 2 relationship of freshwater fish community in Sri Lanka. This "outlier nature" is the success of the C. ornata. It can be concluded that C. ornata will further invade the freshwater bodies and be a major threat to the littoral herbivores, and eventually Chapter 17 Wasantha S. Weliange 162 to the freshwater fishing industry based on the exotic Tilapia. Therefore, strict control measures are needed to prevent range expansion of this invasive alien fish species in Sri Lankan freshwaters. Family Species Fishbase name Local Name Cichlidae Oreochromis niloticus niloticus Nile tilapia Tilapia Cichlidae Oreochromis mossambicus Mozambique tilapia Tilapia Cichlidae Oreochromis urolepis hornorum Wami tilapia Na Cichlidae Tilapia rendalli Redbreast tilapia Tilapia Cichlidae Tilapia zillii Redbelly tilapia Na Cyprinidae Aristichthys nobilis # Bighead carp Bighead carp Cyprinidae Carassius carassius Crucian carp Goldfish Cyprinidae Catla catla # Catla Catla Cyprinidae Cirrhinus cirrhosus # Mrigal Mirigal Cyprinidae Ctenopharyngodon idella# Grass carp Grass carp Cyprinidae Cyprinus carpio carpio Common carp Rata pethiya Cyprinidae Danio rerio Zebra danio Na Cyprinidae Hypophthalmichthys molitrix# Silver carp Silver carp Cyprinidae Labeo rohita Rohu Rohu Helostomatidae Helostoma temminkii Kissing gourami Kissing gourami Kuhliidae Kuhlia marginata ?

As in most artisanal fisheries, assessment of fishing effort is crucial to the management of the artisanal fishery of Parakrama Samudra, an ancient man-made tropical lake in Sri Lanka. Since there were few similarities between alternative ways of expressing effort for the gill-net cichlid fishery in the lake, this study aimed to find the most effective formulation of catch per unit effort (CPUE). The variability of preliminary estimates showed that, before analysis, the data needed to be stratified for different seasons with low and high water levels, and for three geographically distinct areas of the lake. Standardised catch per man was higher in boats operated by smaller numbers of fishermen, but catch per net did not change with the number of nets per boat, and is therefore recommended as the best measure of CPUE. The measure of fishing effort also needs to take account of fishermen who increased their catch by a water-beating technique. The incidence of beating varied with season and area, but could account for a significant portion of the catch. The highest catch efficiencies derived from one-man boats using this technique. Using this method of assessing effort, total annual yield from Parakrama Samudra was estimated at about 120 kg ha-1, a lower value than previously reported.

Sri Lanka is endowed with more than 12,000 reservoirs. Depending on their hydrological regimes, they are broadly categorized into perennial and seasonal reservoirs and are secondarily used for the development of inland fisheries. This paper discusses the importance and status of culture-based fisheries (CBF) in reservoirs of Sri Lanka and assess the impacts of introduction of CBF. The CBF in seasonal reservoirs was initiated in the 1980s and it is well documented. There are around 200,000 ha of perennial reservoirs in Sri Lanka and CBF in perennial reservoirs is a recent development. Introduction of CBF into perennial reservoirs has resulted in significant increases in fish production, increased availability of fresh fish to rural communities, enhanced livelihood opportunities and income for fishers and strengthening the rural economy. Progress achieved so far in respect of seasonal reservoirs has not reached the envisaged levels. Nile tilapia, catla, rohu and mrigal are the main contributory species for fish production through CBF in perennial reservoirs. Although the contribution to fish catches is low, stocking of freshwater prawn (Macrobrachium rosenbergii) is financially feasible. Adequate stocking with suitable species, the existence of active Community Based Organizations (CBOs) and their involvement in planning and implementation of CBF, and the existence of a legal framework which facilitate implementation of activities pertaining to CBF are the key factors for successful implementation and sustainability of CBF in perennial reservoirs.

Present study was carried out to assess the abundance and
diversity of fin-fish and prawn species in the selected five
reservoirs in the Northern Province, Sri Lanka. Fin-fish and
prawns caught by multi-mesh gillnets, and rod and hooks,
were sampled from January to December 2017. Relative
abundance and diversity indices were calculated and,
differences and similarities among reservoirs in different
months were assessed. The hierarchical clustering was
used in constructing dendrogram. Of the 27 finfish species
and two freshwater prawn species identified in total, the
highest number of species were observed in
Muthayankattu reservoir (26 species) while
Puthumurippu reservoir had the lowest (14 species).
Oreochromis niloticus was the dominant species in all the
reservoirs. Small reservoirs (Puthumurippu, Kalmadu and
Muhathankulam) showed high Shannon-Weiner diversity
index and evenness, though low in dominance index,
compared to large reservoirs (Vavunikulam and
Muthayankattu). Selective harvest methods, number of
fishers and seasonal variation of hydro-climatic factors
such as rainfall, strong wind and water level significantly
influenced the diversity of fish species. Increasing fishing
pressure and use of destructive fishing methods during
low water level were the main contributors for diversity
loss in the five perennial reservoirs studied.

The main purpose of this study was to investigate gillnet catch composition and biodiversity caught by 130, 140, and 150 mm (STR) mesh sizes during fishing seasons. This research was conducted in the fishing ground of Bushehr County located in the Persian Gulf from autumn 2018 to spring 2019. Overall, 23 families including 36 genera and 43 species were identified. Spring season with 42 species and winter season with 32 species showed the highest and lowest species biodiversity, respectively. Carangidae family with 7 genera and 8 species, Scombridae family with 3 genera and 4 species, and Dasyatidae with 3 genera and 4 species were the families with the highest species biodiversity. Scomberomorus commerson and Thunnus tonggol with 23.45% and 21.84% in autumn, 20.15% and 25.85% in winter, 21.9% and 19.78% in spring showed the most abundance percentages, respectively. The 130 mm mesh size and spring season had the highest abundance, diversity, and the number of caught species in comparison with other mesh sizes and seasons. Two-ways ANOVA results showed that the effects of mesh sizes and seasons on the calculated metrics were significant (P<0.05), but their interaction effect was not significant (P>0.05). The highest and lowest Jaccard (J) and Sørensen (S) seasonal similarities were between autumn and spring (J: 0.805, S: 0.892) and autumn and winter (J: 0.561, S: 0.719), respectively. The results of non-metric multidimensional scaling analysis showed that 130 and 140 mm mesh sizes had overlap in terms of the fish abundance and catch composition. Cluster analysis also showed the highest similarity between S. commerson and T. tonggol, and Euthynnus affinis and Scomberoides commersonnianus.

Fish has historically played an important role in food security in many countries and contributes to do so in globally, providing 15-20 percent of animal protein intake. Fish farming has been practiced in different parts of the world like Europe. At present, the country Ethiopia has an estimated annual total exploitable fish potential of 51,481 tons, which can meet only 79 percent of the current actual demand, 55 percent of the projected demand in 2010 and 44 percent of the projected demand in 2015, based solely on population size. Lake Tana, Ashenge, Hayk, Koka, Ziway, Langano, Awassa, Abaya and Chamo are among the Potential fish rich lakes found in Ethiopia. The main commercial species contributing to the total landing are Oreochromis niloticus, Labeohori, Clarias gariepinus, Barbus species and LatesniloticusFish is highly nutritious, so even small quantities can improve people's diets. Several reasons like environmental degradation, poor fisheries development, increased illegal fisheries, traditional fishing system and climatic changesattributed to the low production in the country.

In the present paper, an attempt is made to investigate whether the body shape indices can be used to predict food habits of fish species in three reservoir fish communities of Sri Lanka. The present analysis is based on the studies on food and feeding habits of fish species and their body shape indices in three Sri Lankan reservoirs, namely Minneriya, Udawalawe and Victoria. Body proportions of individual fish species were determined as P 1 (= Maximum height of the body/ Maximum width of the body) and P 2 (= Total length/ Maximum height of the body), which were found to be negative curvilinearly related. Trophic indices (T i ) of individual fish species were determined on the basis of trophic level of each food item and the fractions of all food items consumed by fish species, which ranged from 1 for exclusively herbivorous species to 3 for carnivorous species. A negative logarithmic relationship between P 1 and T i indicates that laterally compressed fish species with deep bodies feed on lower trophic levels in the food web. On the other hand, dorso-ventrally flattened species with low P 1 have higher trophic indices than those with high P 1 . The positive logarithmic relationship between P 2 and T i also indicates that short, deep-bodied fish species representing low P 2 values feed on lower trophic levels whereas slender, long-bodied species with high P 2 values feed on higher trophic levels. The body shapes, measured as simple body proportions of the definitions of P 1 and P 2 , can therefore be used to predict feeding habits of fish.