Tropical Freshwater Biology https://www.ajol.info/index.php/tfb <em>Tropical Freshwater Biology</em> promotes the publication of scientific contributions in the field of freshwater biology in the tropical and subtropical regions of the world. One issue is published annually but this number may be increased. Original research papers and short communications on any aspect of tropical freshwater biology are acceptable. Review articles relevant to the tropics and books for review are welcome. Articles solely concerned with the physical and chemical environment and theoretical issues will be considered occasionally. Idodo Umeh Publishers Limited en-US Tropical Freshwater Biology 0795-0101 Authors should transfer the copyright of papers to Idodo Umeh Publishers Limited,Benin City,Nigeria. Publications may not be reproduced, stored in retrieval systems or transmitted in any form or any means without the written permission of the Publishers. Boosting fish production in Cameroon: Incorporated fish-rice farming versus earthen pond fish culture in Buea, Mount Cameroon region https://www.ajol.info/index.php/tfb/article/view/205435 <p>Wetland incorporated fish-rice farming (FRF) is a possible solution to the problem of high costs of fish feeds in aquaculture in Cameroon. For 12 weeks, at the University of the Buea (UB) the growth of the fish, <em>Clarias gariepinus</em> in concurrent culture with rice (Oryza sativa, L.) in two rice plots (rice plot 1 and rice plot 2stocking sites) in the University of Buea wetland and in two earthen ponds (fish pond 1 and fish pond 2stocking sites) fed compounded diet at 5% body weight was investigated. Physico-chemical water quality parameters of all the fish culture sites were monitored. Mean fish weight gain was significantly higher (P&lt;0.01) in the wetland rice plots (329.21±44.35g) than in the two earthen ponds (30.01±2.84g). Apart from low mean dissolved oxygen values in the rice plot 1 (3.14±1.19 mg/L) and rice plot 2 (2.18±0.23 mg/L), mean values for physico-chemical water quality parameters were within recommended ranges for <em>C. gariepinus</em> growth in all the four culture sites. This FRF experiment proved a better practice in fish growth than the conventional earthen pond culture in Buea, Cameroon. Its adoption by local fish farmers is recommended.</p> <p><strong>Keywords:</strong> Wetland integrated fish-rice farming<em>, C gariepinus</em>, earthen pond culture, and fishpond.</p> B.O Oben A.F Narika M.A Arrey J Ebobenow M.P Oben Copyright (c) 2021-04-29 2021-04-29 29 2 1 20 10.4314/tfb.v29i2.1 Antibiogram of faecal <i>Streptococci</i> isolates for pollution source determination in the Ikpoba river, Benin City https://www.ajol.info/index.php/tfb/article/view/205436 <p>Water samples from various sites of the Ikpoba River, Benin City, were bacteriologically analysed to determine bacterial indicators of faecal pollution and heterotrophic bacterial concentration. Sampling points 1 was the point of drainage discharge from the University of Benin Teaching Hospital, 2 was at the Bridge at Upper Mission Road, 3 was the point of effluent discharge from Oredo Local Government Area Abbatoir, 4 was at the Bridge along Benin-Agbor Road and 5 was the point of effluent discharge from Guinness Nigeria PLC. Faecal coliform count was generally high in all sample sites with the point of discharge of effluent from the Abbatoir showing the highest mean count of 1.51 × 107 cfu/ml; and the Bridge at Upper Mission Road had the lowest mean count of 1.20 × 107 cfu/ml. Faecal streptococci count was highest at the point of discharge of effluent from Guinness Nigeria PLC at 8.21 × 107 cfu/ml. while the Bridge at Upper Mission Road had the lowest faecal <em>streptococcus</em> count of 5.83 × 106 cfu/ml. Antibiotic Resistance Patterns of faecal streptococci isolates on day 1 were observed to be more susceptible to the battery of antibiotics than faecal <em>streptococci</em> isolates on days 2 and 3. The results of the ratio of faecal coliform to faecal streptococci and the antibiotic resistance pattern on faecal <em>streptococci</em> showed that faecal pollution of the Ikpoba River has both human and animal origin. There are undoubted risks to human health from surface water polluted with animal faeces, nevertheless, it is human faeces that represent a much greater risk and thus constant investigations should be carried out by environment monitoring agencies to evaluate the pollution status of the river and residents around the river should administer filtration techniques before domestic use.</p> <p><strong>Keywords:</strong> faecal pollution, faecal streptococci, antibiotic resistance patterns</p> C.O Sekegor Copyright (c) 2021-04-29 2021-04-29 29 2 21 34 10.4314/tfb.v29i2.2 Effects of light matrix organics (probiotic) on the growth, feed digestibility, carcass and blood parameters of African catfish, <i>Clarias gariepinus </i> https://www.ajol.info/index.php/tfb/article/view/205437 <p>Cameroon’s fish protein consumption levels remain inadequate due to low fish production. The effects of Light Matrix Organics (LMO), a probiotic combination on the growth performance, feed digestibility, blood and carcass composition of the African catfish, <em>Clarias gariepinus</em> were investigated. Probiotics are live microorganisms which when administered in adequate amounts confer health benefits on the host. A basal diet was formulated and supplemented with LMO at 0.0 ml/kg (T0) as control; 1.66 ml/kg (T1); 2.49 ml/kg (T2); 3.32 ml/kg (T3) and 4.15 ml/kg (T4) and fed to 340 Clarias gariepinus fingerlings in two blocks (with average fish weights of 1.00±0.40 g and 0.1±0.05 g respectively), for sixty (60) days in replicate plastic tanks. Fish were fed twice daily at 4% body weight. Results show that the Mean weight gain, Specific growth rate and Protein efficiency ratio were significantly highest (P&lt;0.05) in fish fed diets supplemented with LMO at 4.15 ml/kg (T4) and lowest in T0 (control). Apparent Digestibility Coefficients (ADC) of <em>C. gariepinus</em> for Dry Matter% and Crude Protein% decreased significantly in the general order: T4&gt;T3&gt;T2&gt;T1&gt;T0, except for Crude Protein which was significantly higher (P&lt;0.05) in T3 than in T4. ADC Lipid% was higher (P&lt;0.05) in both T2 and T4 than in all other treatments while ADC Energy was highest (P&lt;0.05) in T2. Blood parameters were significantly higher (P&lt;0.05) in LMO supplemented diets except for haematocrit (Ht) and red blood cells (RBC). Carcass nutrients differed significantly with LMO supplemented diets producing significantly lower (P≤0.05) fat but storing more energy than fish on the control diet. Incorporating LMO in treatment T2 was significantly more (P&lt;0.05) economically efficient than other treatments. The supplementary use of LMO at the rate of 2.49ml/kg fish feed is therefore recommended based on the high economic efficiency and above average growth performance.</p> <p><strong>Key words</strong>: probotic, light matrix organics,<em> Clarias gariepinus</em>, growth performance, digestibility, economic efficiency.</p> B.O Oben T.D.G Tiku P.M Oben Copyright (c) 2021-04-29 2021-04-29 29 2 35 46 10.4314/tfb.v29i2.3 Acute toxicity of <i>Jatropha curcas</i> (barbados nut) latex extracts to <i>Oreochromis niloticus</i> juveniles https://www.ajol.info/index.php/tfb/article/view/205438 <p>The effects of the latex extract of<em> Jatropha curcas</em> on mortality rate, opercular ventilation rate and some behavioural responses of <em>Oreochromis niloticus</em> juveniles were investigated under laboratory conditions over a 96 hours exposure period. Juveniles of <em>Oreochromis niloticus</em> (Trewavas) were exposed in plastic aquaria to 0.00mg.l-1 (control), 10mg.l-1, 15mg.l-1, 20mg.l-1, 25mg.l-1 and 30mg.l-1. Their opercular beats per minute, tail fin beats per minute, mortality and probit kill were determined. Symptoms of toxicosis observed include agitated swimming, loss of equilibrium, air gulping, periods of quiescence and death. Within 24 hours the opercular ventilation beats and tail fin beats of the exposed fish were significantly higher than in control fish (p&lt;0.05). At 72 hours and 96 hours the opercular and tailfin beats in the control fish were significantly higher (P&lt;0.05) than the exposed fish. The 96 hours LC50 was determined as 5.23 ml/l. Include significance of this study to conclude abstract.</p> <p><strong>Key words</strong>: acute toxicity, Jatropha curcas latex extract, Oreochromis niloticus, haematological parameters.</p> M Usman J.A Umaru A.A Kigbu Copyright (c) 2021-04-29 2021-04-29 29 2 47 58 10.4314/tfb.v29i2.4 Water renewal in static systems: Impacts on productivity and survival in Clarias gariepinus (Burchell, 1822) https://www.ajol.info/index.php/tfb/article/view/205439 <p>The impact of water renewal in a static system on the growth and survival of <em>Clarias gariepinus</em> fingerlings was investigated under six different treatments, namely: T<sub>1</sub> (daily water renewal), T<sub>3</sub> (three days water renewal), T<sub>5</sub> (five days water renewal), T<sub>7</sub> (seven days water renewal), T<sub>9</sub> (nine days water renewal) and T<sub>14</sub> (fourteen days water renewal). Results showed that growth performance and survival was significantly (P&lt; 0.05) affected by the water renewal frequencies. After six weeks, weight gain, daily weight gain, specific growth rate, final body weight, was significantly higher in T<sub>5</sub> (P&lt; 0.001). Likewise, survival in T<sub>5</sub> was significantly higher compared to other groups (P&lt; 0.001). For all evaluated parameters, T<sub>14</sub> had the least performance. Slow response to feeding, slow movement and hanging on the water surface was observed in T<sub>9</sub> and T<sub>14</sub>. Daily water renewal tank had significantly (p &lt; 0.05) higher dissolved oxygen (04.52 mg L<sup>-1</sup>) while electrical conductivity (800.00 μScm<sup>-1</sup>) was significantly higher in T<sub>14</sub> (P&lt; 0.001). From the result, the growth and survival of the catfish fingerlings in T<sub>5</sub> are superior to other renewal regimes. Therefore, for optimum growth and productivity of African catfish fingerlings reared in a static system, it is recommended that water renewal be performed every five days.</p> <p><strong>Key words</strong>: <em>Clarias gariepinus</em>, water renewal, weight gain, water quality, behaviour, feed conversion ratio, specific growth rate</p> P.A Opute G.F Odion Copyright (c) 2021-04-29 2021-04-29 29 2 59 67 10.4314/tfb.v29i2.5 Food items and feeding habits of two Nothobranchiidae, <i>Epiplatys chaperi sheljuzhkoi</i> (poll, 1953) and <i>Nimbapanchax petersi</i> (sauvage, 1882) in Banco river, Côte d’ivoire https://www.ajol.info/index.php/tfb/article/view/205440 <p>Food and feeding habits of two Nothobranchiidae species, <em>Epiplatys chaperi sheljuzhkoi</em> (Poll, 1953) and <em>Nimbapanchax petersi</em> (Sauvage, 1882) from Banco River were investigated between January and December 2016. Stomach contents of 119 and 397 individuals of <em>E. sheljuzhkoi</em> and <em>N. petersi</em> were respectively analyzed, ranging in size from 13 and 55 mm, 11 and 48 mm standard Length, respectively. Formicidae being terrestrial insects, constituted the main prey (RI&gt;50) of both species, and aquatic insect larvae (Hydrophilidae and Chironomidae) were secondary or accessory preys. The food items in stomach showed a small spectrum in <em>E. sheljuzhkoi</em> than <em>N. petersi</em> but differences were not significant (Chi-square, p&gt;0.05). Diet composition of both species showed little variation according to seasons, sampling zones and size groups (Anova, p&gt;0.05). However, a decreasing trend in terrestrial insects and an increase of other preys in stomach contents has been observed from upstream to downstream. For ontogenic variation, large specimens group fed much more on aquatic insect larvae, fish scales and macrophytes than small size group. This work indicated that both species fed on a small range of prey items dominated by insects in Banco River and could be considered strict insectivorous predators. This work concludes that both species have similar diets and the canopy cover of Banco forest plays an important role in the feeding and conservation of these species.</p> <p><strong>Key words:</strong> Epiplatys, Nimbapanchax, canopy cover, diet, terrestrial insects, Formicidae, predator.</p> D.A Kouamé Ouanko Y.A Konan T.M Kamelan B.G Gooré Z.M Gogbé Copyright (c) 2021-04-29 2021-04-29 29 2 69 85 10.4314/tfb.v29i2.6 Helminth parasites of cultured <i>Clarias gariepinus</i> and <i>Tilapia zillii</i> in Uyo, Akwa Ibom State, Nigeria https://www.ajol.info/index.php/tfb/article/view/205441 <p>The study examined helminth parasites of cultured <em>Clarias gariepinus</em> and <em>Tilapia zillii</em> in Uyo, Akwa Ibom State. A total of 60 fish samples (30 each of <em>C.gariepinus</em> and <em>T. zillii</em>) were subjected to parasitological examinations. Results revealed a total of 47(78.33%) fishes infected with various species of parasites: Nematodes (<em>Camallanus polypteri, Paracamallanus cyathopharynx, and Procamallanus laevionchus</em>), Cestodes (<em>Polyonchobothrium torulosus and P. clariae</em>) and Trematodes (<em>Dactylogyrus extensus and Glossiduim pedatum</em>) in decreasing order of abundance. Out of the 60 fish samples examined, 47 were infected with 219 parasites: 142(64.84%) nematodes, 40(18.26%) cestodes and 37(16.89%) trematodes. A total of 159(72.60%) parasites were recovered from <em>C. gariepinus</em> out of which 103(64.78%) were nematodes, 19(18.45%) were cestodes and 37(35.92%) were trematodes. While 60(27.40%) parasites were recovered from <em>T. zilli,</em> of which 39(65.00%) were nematodes and 21(35.00%) cestodes. No trematode was observed in the tilapia. The overall prevalence of parasitic infection was 78.33%. The results of chi square analysis showed that females of both species had significantly higher (P&lt;0.05) prevalence of infection 27(84.4%) than males 20(71.4%). Also, <em>C. gariepinus</em> had higher infection rate of 25(83.33%) when compared to 22(73.33%) recorded in <em>T. zillii</em>.</p> <p><strong>Key words:</strong> fish parasites, aquaculture, prevalence, <em>C. gariepinus, T. zillii</em></p> M.U Effiong N.E Obot Copyright (c) 2021-04-29 2021-04-29 29 2 87 94 10.4314/tfb.v29i2.7 Biotreatment of brewery effluents for aquaculture use using autochthonous fungi https://www.ajol.info/index.php/tfb/article/view/205442 <p>The potential of reducing environmental impact of untreated brewery effluent was investigated. Although concentrations of pollutants in such effluents are usually considered low and inadvertently discharged into adjacent urban drainage facility, mycoremediation to remove dissolved inorganic nutrients in effluent was conducted with a view for aquaculture use in Uyo metropolis, southeast Nigeria. Raw brewery effluents were obtained and screened for indigenous microbial flora. Autochthonous fungi isolated included <em>Aspergillus niger, Verticillium sp</em>. and <em>Mucor sp</em>. The potential use of isolates as alternative treatment of brewery effluents was analyzed for treated and control groups. Treated group was inoculated with pure colonies of fungi isolates while the control group received no fungi treatment or modification. Both groups were incubated for seven (7) days. Thereafter, the physicochemical parameters of raw and remediated effluents were analysed and compared with National Environmental Standards and Regulations Enforcement Agency (NESREA) and aquaculture standards. Results confirmed suitability of autochthonous fungi isolates in mycoremediation of brewery effluent for aquaculture and irrigation.</p> <p><strong>Key words:</strong> effluent toxicity, industrial pollution, mycoremediation, aquatic ecosystem, Uyo</p> J.P Udoh A.J Otoh M.E Udang Copyright (c) 2021-04-29 2021-04-29 29 2 123 134 10.4314/tfb.v29i2.9