Reproductive biology and feeding habits of the catfish Clarias gariepinus (Burchell) (Pisces: Clariidae) in lake Awassa, Ethiopia

Dadebo, Elias

doi:10.4314/sinet.v23i2.18168

Cited by 51 publications

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“…Our study, therefore, focused on these three target species assuming that the fishing pressure might be high and regulative measures might be needed. The biology and ecology of these species have been studied in different water bodies in Ethiopia (Admassu, 1996;Tadesse, 1997;Wudneh, 1998;Tadesse, 1999;Dadebo, 2000;Teferi, Admassu, & Mengistou, 2004;Tesfaye & Tadesse, 2008). The growth of these species has also been reported in other areas, but very little is known about their vital population parameters and exploitation status in Lake Koka.…”

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Stock assessment of fishery target species in Lake Koka, Ethiopia

Tesfaye

Wolff

2015

RBT

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Effective management is essential for small-scale fisheries to continue providing food and livelihoods for households, particularly in developing countries where other options are often limited. Studies on the population dynamics and stock assessment on fishery target species are thus imperative to sustain their fisheries and the benefits for the society. In Lake Koka (Ethiopia), very little is known about the vital population parameters and exploitation status of the fishery target species: tilapia Oreochromis niloticus, common carp Cyprinus carpio and catfish Clarias gariepinus. Our study, therefore, aimed at determining the vital population parameters and assessing the status of these target species in Lake Koka using length frequency data collected quarterly from commercial catches from 2007-2012. A total of 20 097 fish specimens (distributed as 7 933 tilapia, 6 025 catfish and 6 139 common carp) were measured for the analysis. Von Bertalanffy growth parameters and their confidence intervals were determined from modal progression analysis using ELEFAN I and applying the jackknife technique. Mortality parameters were determined from length-converted catch curves and empirical models. The exploitation status of these target species were then assessed by computing exploitation rates (E) from mortality parameters as well as from size indicators i.e., assessing the size distribution of fish catches relative to the size at maturity (L m ), the size that provides maximum cohort biomass (L opt ) and the abundance of mega-spawners. The mean value of growth parameters L ∞ , K and the growth performance index ø' were 44.5 cm, 0.41/year and 2.90 for O. niloticus, 74.1 cm, 0.28/year and 3.19 for C. carpio and 121.9 cm, 0.16/year and 3.36 for C. gariepinus, respectively. The 95 % confidence intervals of the estimates were also computed. Total mortality (Z) estimates were 1.47, 0.83 and 0.72/year for O. niloticus, C. carpio and C. gariepinus, respectively. Our study suggest that O. niloticus is in a healthy state, while C. gariepinus show signs of growth overfishing (when both exploitation rate (E) and size indicators were considered). In case of C. carpio, the low exploitation rate encountered would point to underfishing, while the size indicators of the catches would suggest that too small fish are harvested leading to growth overfishing. We concluded that fisheries production in Lake Koka could be enhanced by increasing E toward optimum level of exploitation (E opt ) for the underexploited C. carpio and by increasing the size at first capture (Lc) toward the L opt range for all target species. Rev. Biol. Trop. 63 (3): 755-770. Epub 2015 September 01.

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Stock assessment of fishery target species in Lake Koka, Ethiopia

Tesfaye

Wolff

2015

RBT

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“…There are no rivers to the west or north of the lake but from the eastern highlands or hills there is one perennial river which fed by Wesha and Butra rivers near Wonde Genet that drains through Tikurwuha river to Lake Hawassa with mean monthly flow rate of 6−7 m 3 /s with only slight seasonal variation (Halcrow, 2010). The maximum depth of the lake is 22 m and the mean depth of 11m (Dadebo, 2000).Evaporation from the Lake Hawassa is estimated to be 1710 mm/year (Gugissa, 2004) and the total volume of the lake water is 1.3 km 3 (Tenalem, 1998). The choices of sampling stations were based on the various uses of the lake water and their location, relative magnitude and importance.…”

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confidence: 99%

Physicochemical and Biological Water Quality Assessment of Lake Hawassa for Multiple Designated Water Uses

Worako¹

2016

J. Urb. and Environ. Engng

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Lake Hawassa is one of the Major Ethiopian Rift Valley Lakes which is situated in southern regional state, which has a closed basin system and receives water from only Tikurwuha River and runoff from the catchment. Quality of the lake water is vital for the surrounding community for proper and safe use of the lake. The present study was designed to examine the physicochemical and biological water quality suitability for multiple purposes and to determine trophic state index of the lake for a period of three months from December to February, 2011/12. Water samples were collected from the lake on monthly basis and analyzed for all water quality parameters by using standard methods. Data analysis was performed by descriptive, multivariate analysis (MANOVA) and Tukey-Kramer test. The overall water quality parameters analytical results have been observed as pH (7. . The values of the whole analyzed parameters have shown significant variation in site (P<0.05). As irrigation water quality mainly focuses on the indices of SAR and EC/TDS, the lake water is in good condition for the purpose. The values of trace heavy metals were under permissible limits for multiple aspects. On average, the trophic state index of the Lake Hawassa was hypereutrophic (TSI = 72.6), as Carlson value category. In general, the lake water is not suitable for drinking, recreational and irrigation of some raw consuming crops but it is suitable for aquatic life.

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“…The three minnow fish that are not fished due to their small size are the straightfin barb (Barbus paludinosis Peters 1852), the black lampeye (Aplocheilichthys antinorii Vinciguerra, 1883) and the stone lapping minnow (G. quadrimaculata) (Elias Dadebo, 2000). The commercial fishery mainly rests on O. niloticus that accounts for over 85 % by weight to the total annual landings followed by C. gariepinus (14%) and L. intermedius (<1%).…”

Section: The Study Areamentioning

confidence: 99%

“…However, it is ecologically important, since it is used as a prey fish for Clarias gariepinus (Burchell, 1822) and Labeobarbus intermedius (Rüppell, 1836), which are commercially important fish species in Lake Hawassa (Elias Dadebo, 2000). Accordingly, knowledge on the feeding habits of G. quadrimaculata helps to understand energy flow among the different trophic levels of organisms in the lake.…”

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Feeding habits and trace metal concentrations in the muscle of lapping minnow <i>Garra quadrimaculata</i> (Rüppell, 1835) (Pisces: Cyprinidae) in Lake Hawassa, Ethiopia

Tekle-Giorgis¹,

Yilma²,

Dadebo³

2016

mejs

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Diet composition and trace metal concentration in the muscle of the lapping minnow Garra quadrimaculata (Rüppell, 1835) was investigated to study the trophic status of the species as well as to assess the level of bioaccumulation of heavy metals in the body of the fish. The study was conducted based on 328 gut samples collected from February to March (dry months) and from August to September (wet months) of the year 2011. Frequency of occurrence and volumetric methods were employed in this study. Detritus, fish eggs, macrophytes, phytoplankton and insects occurred in 54.9%, 16.2%, 43.9%, 56.4% and 26.6% of the guts, respectively and comprised 27.1%, 22.2%, 18.2%, 18.2% and 14.1% of the total volume of food, respectively. The proportions of different food items consumed varied during the dry and wet months. Fish eggs and detritus were the dominant food items during the dry months. Macrophytes and insects were also common in the diet. During the wet months, phytoplankton was the most dominant food item (33.5% by volume). Macrophytes, detritus and insects were also important in the diet. The mean volume of fish eggs and phytoplankton decreased as the size of fish increased while the contributions of detritus, insects and macrophytes increased with fish size. The present study clearly indicated that G. quadrimaculata in Lake Hawassa is omnivorous in its feeding habits. Out of the seven analyzed trace metals (Cr, Mn, Zn, Cu, Cd, Pb and Ni), Cd, Pb, and Ni were below detection limits. There was a significant difference (p<0.05) between the mean concentrations of Zn and Cr in the muscle of the fish in the dry and wet months. The concentration of Zn in the dry month was significantly lower than its concentration in the wet months (p<0.05). By contrast, the concentration of Cr in the dry months was significantly higher than its concentration in the wet months. There were no significant variations in the concentrations of Mn and Cu between dry and wet months. There was no sign of bioaccumulation of the investigated trace metals as the fish grew older. The detected elements were compared with different standards and found to be below the maximum permissible limits for human consumption.

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Reproductive biology and feeding habits of the catfish Clarias gariepinus (Burchell) (Pisces: Clariidae) in lake Awassa, Ethiopia

Cited by 51 publications

References 0 publications

Stock assessment of fishery target species in Lake Koka, Ethiopia

Stock assessment of fishery target species in Lake Koka, Ethiopia

Physicochemical and Biological Water Quality Assessment of Lake Hawassa for Multiple Designated Water Uses

Feeding habits and trace metal concentrations in the muscle of lapping minnow <i>Garra quadrimaculata</i> (Rüppell, 1835) (Pisces: Cyprinidae) in Lake Hawassa, Ethiopia

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