Journal of Aquatic Sciences <p>The <em>Journal of Aquatic Sciences</em> publishes articles on problems and issues in Aquatic Sciences from all parts of the world. The journal accepts for publication manuscripts of very high international standard containing reports of original scientific research. Acceptable topics include aquatic biology, aquatic resources management, aquatic ecotoxicology and pollution, fish physiology, nutrition, health, breeding, population dynamics, fish processing and preservation.</p><p>Other websites related to this journal: <a title="" href="" target="_blank"></a></p><p> </p> en-US Copyright for articles published in this journal is retained by the journal. (Dr. O. A. Davies) (Editor) Fri, 16 Apr 2021 08:38:22 +0000 OJS 60 Assessment of Water Pollution Indices of Two Anthropogenic Impacted Rivers in Southern Nigeria <p>Freshwater ecosystems afford essential needs and services to humans and have not been spared the effects of anthropogenic pressures exacerbated by increasing urbanization and industrialization. The study was undertaken in two southern inland rivers in Edo State, Nigeria, following concerns that the increasing human population in the region, coupled with indiscriminate discharges into rivers could erode water quality and elevate metal concentrations above allowable limits. Water samples were collected and analyzed for heavy metal concentrations using standard procedures. The results showed that metal concentrations were generally within national and international limits for drinking water with exceptions in cadmium and lead. Water pollution indices showed metal pollution index for cadmium (1037, 757) and lead (503, 379) in Ovia and Ossiomo Rivers respectively. These values far exceeded the critical level of 100 with a high contamination index (&gt;6) of cadmium in both rivers. Water quality index from physico-chemical analysis indicated poor conditions in Ossiomo River relative to very poor water conditions in Ovia River. The study demonstrated that cadmium and lead were the major contributors to the adverse environmental conditions in both rivers. Thus, incessant anthropogenic pressures adversely affected water quality of these rivers rendering them unsuitable for human use. This would potentially have serious ecological and human health implications as chronic effects may be unquantifiable.</p> <p><strong>Keywords:</strong> Ovia and Ossiomo Rivers, heavy metal, water quality index, contamination index</p> J.A Edoreh, J.I Izegaegbe, E.C Osimen, C.U Inegbenosun, H.A Ojagefu, E Weyinmi Copyright (c) Mon, 12 Apr 2021 00:00:00 +0000 Assessment of Heavy Metal Distribution in Tilapia (<i>Oreochromis niloticus</i>) Samples from Uta Ewa Creek, Niger Delta, Nigeria <p>The Uta-Ewa Creek is one of the largest aquatic commercial hubs in the Niger Delta, Nigeria. As a result of household activities, urbanization as well as the continuous industrial and agricultural growth, the health of this aquatic system is potentially deteriorating and under threat. This study was conducted to determine trace metal toxicity in tilapia species caught along the creek. Heavy metal concentration in fish tissue was analyzed using standard procedure. Results revealed that concentration of cadmium ranged from 1.708 to 1.963 mg/kg (mean = 1.82 ± 0.099 mg/kg), chromium: 0.003 to 0.016 mg/kg (mean = 0.0 ± 0.005 mg/kg), copper: 1.829 to 2.558 mg/kg (mean = 2.27 ± 0.354 mg/kg), iron: 2.104 to 2.601mg/kg (mean = 2.38 ± 0.189 mg/kg), lead: 0.004 to 0.067 mg/kg (mean = 0.04 ± 0.024 mg/kg), manganese: 1.987 to 2.485 mg/kg (mean = 2.21 ± 0.188 mg/kg) and zinc: 1.019 to 2.986 mg/kg (mean = 1.69 ± 0.811 mg/kg). The average heavy metal accumulation in fish tissue followed this sequence: Fe&gt;Cu&gt; Zn&gt;Mn&gt;Cd&gt;Cr&gt;Pb.The depth of accumulation of heavy metals revealed in this study was higher than the recommended levels by WHO, FEPA and USEPA. This indicated bioaccumulation. Inference from this study showed that, tilapia fish from Uta-Ewa Creek may be unsafe for human consumption. Consequently, appropriate monitoring of the health of this aquatic system is recommended.</p> <p><strong>Keywords</strong>: Heavy metals, bioaccumulation, concentration, monitoring, pollution</p> N.O Abiaobo, I.E Asuquo, I.N Ejiogu Copyright (c) Tue, 13 Apr 2021 00:00:00 +0000 Sub-Lethal Toxicity of Dichlorvos on Gills and Liver of Juvenile <i>Heterobranchus longifilis</i> <p>The study assessed the histological changes in the structure of gills and liver of juvenile <em>Heterobranchus longifilis</em> after exposure to varying sub-lethal concentrations of Dichlorvos. The fish, 120specimenswith mean weight of 47.33±2.31g and total length 10.67±0.58cm were selected and used for the experiment. Test fish were treated with concentrations of 0.00, 0.01, 0.015 and 0.02mg/l of Dichlorvos representing treatments T1, T2, T3 and T4 respectively. The study was carried out in a static renewal bioassay system. Fish samples were stocked in plastic bowls of 75litre capacity and the exposure period was7 days. All analyses were done using standard methods. The results showed prominent changes in the gills which included: partial epithelia lifting, hyperplasia, heavy degeneration changes, oedema, congestions and vacuolization. Changes in the liver included: congestion with sub-massive necrosis, liver parenchymal cell prominent with fatty/glycogen degeneration, hepatocytes and enlargement of portal tract. Histopathological changes on the two tissues increased with concentration of dichlorvos with severe damages observed at higher concentrations. This study showed that the use of dichlorvos as pesticides, which often find their way into the aquatic system, may have negative effects on fish. Thus, the use of organic pesticides should be encouraged.</p> <p><strong>Keywords</strong>: Histopathology, sub-lethal, Heterobranchus longifilis, dichlorvos, gills and liver</p> I.O Obaroh, D.D Attah, M.H Zuru Copyright (c) Tue, 13 Apr 2021 00:00:00 +0000 Growth Performance of <i>Clarias gariepinus</i> Juveniles fed Diets Supplemented with Garlic (<i>Allium sativum</i>) Powder <p>The study investigated effects of graded levels of garlic (<em>Allium sativum</em>) powder supplemented diets on the growth performance of <em>Clarias gariepinus</em> juveniles. Five treatments comprising of twelve<em> C. gariepinus</em> juveniles of mean weight 7.52±0.00g per treatment were used in the study. Fish in each treatment was fed twice daily with experimental diets formulated with different inclusion levels of garlic powder at 0%, 1%, 2%, 3% and 4%; designated as control, T1, T2, T3 and T4 respectively. Fish were fed at 5% of their body weight and feeding trial lasted for 56 days. Analysis of the physico-chemical parameters of culture water was also carried out. Collected data were analysed and results showed that water temperature ranged from 27.0 to 28.5oC, pH ranged between 7.58 and 7.79, dissolved oxygen levels varied from 6.20 to 6.50mg/l, while ammonia content was observed to be between 2.33 and 2.73mg/l. Fish fed 3% garlic inclusion diet had the highest mean weight gain (MWG) of 40.63±30.04g, percentage weight gain (PWG) of 541.73% and specific growth rate (SGR) of 2.79±0.00%/day when compared with those on other treatments. The least PWG (345.25%) and SGR (1.95±0.00) were observed in the control and fish fed 1% garlic inclusion diets. However, MWG values were similar (p &gt; 0.05) in T1 and T4. Fish fed diets with 2% garlic inclusion had the highest FCR (3.22±0.04) while the least value (2.29±0.03) was observed in T3. Results of the crude protein contents of treated fish carcass increased in all dietary treatments. Inference from this study indicated that incorporation of garlic meal in fish diets at 3% inclusion level improved growth performance and proximate composition of <em>C. gariepinus</em> juveniles.</p> <p><strong>Keywords:</strong> Catfish, functional foods, garlic, nutrient utilization, weight gain</p> K.O Elezuo, E.G Okeke, V.O Olarewaju, B.E Quadri Copyright (c) Fri, 16 Apr 2021 00:00:00 +0000 Species Composition, Dominance and Similarity Index of <i>Macrobrachium vollehovenii</i> and <i>M. Felicinum</i> in Akor River, Ibere, Ikwuano, Nigeria <p>Occurrence and abundance of<em> Macrobrachium vollehovenii</em> and <em>Macrobrachium felicinum</em> were studied in Akor river, Ibere, Ikwuano, Nigeria. The area density method of sample collection was employed. The river was delineated into three stations: A, B and C and prawn specimen were collected fortnightly. Sample collection lasted for 24 months. Species composition, dominance and similarity index were calculated using standard methods. Chi square test was used to compare the dominance of both species in the River. Results showed that station A had a total catch composition of 1,407 (29.4%), station B recorded 1,689 (34.73%) and the highest catch was obtained in station C having 1,763 (36.2%). The overall total catch of 4,859 was recorded. Results also showed that <em>M. vollehovenii</em> dominated the river with a total number of 3,620 (75%) while <em>M. felicinum</em> had a total catch of 1,239 (25%). Ponderal index was 53.7 and 44.7 for <em>M. vollehovenii</em> and <em>M. felicinum</em> respectively and a similarity index of 1 for both species was observed. Statistical analysis showed that there was significant difference (p&lt;0.05) between dominance of these species in Akor river. Inference from the results showed that these species are present as non-target organism in this river.</p> <p><strong>Keywords</strong>: Occurrence, abundance, Macrobrachium species, fresh water, crustacean</p> J.I Ukagwu, D.C Anyanwu, M.C Orgi, S Ohaturonye, C Dan-Uchegbu Copyright (c) Fri, 16 Apr 2021 00:00:00 +0000 Economic Evaluation of Three Hormonal Preparations in Artificial Propagation of <i>Heterobranchus longifilis</i> (Valenciennes, 1840) <p>The economic evaluation of three hormonal preparations: ovaprim, ovulin and carp pituitary extract (C.P.E) in artificial propagation of <em>Heterobranchus longifilis</em> was investigated. A total of twelve brood fishes (nine females and three males) of eighteen months old were used for the experiment. The females were divided into three groups. Each group was induced to spawn with each of the hormones. Pooled sperm from the three males were used to fertilize the eggs obtained from the females. Effects of the hormones on the fecundity was investigated to help address the economic values. The results showed that the cost of inducing 1.20kg female to yield 42.83g, 57.60g, and 35.10g of eggs were ₦480.39, ₦225.00 and ₦175.00, for C.P.E, ovaprim and ovulin respectively. Profitability index for ovaprim, ovulin, and C.P.E was 5.58, 3.44, and 3.92, respectively. Indicating that, cost of production accounted &lt;20% for Ovaprim and &lt;30% for both ovulin and C.P.E of the total variable cost. The production was more profitable with ovaprim than ovulin and C.P.E. The study has provided data, comparing the effectiveness of the hormones, revealing that the three hormones can be used for artificial propagation of <em>H. longifilis</em> with varied degree of economic implication. However, ovaprim is highly recommended to hatchery users for optimum performance.</p> <p><strong>Keywords</strong>: <em>H. longifilis,</em> ovaprim, ovulin, C.P.E and economic evaluation.</p> P.S Asangusung, A Uka, A Otoh Copyright (c) Fri, 16 Apr 2021 00:00:00 +0000 Viability of Different Strains of <i>Lactobacillus fermentum</i> in Feed and Effects on Growth Performance of <i>Clarias gariepinus</i> Fry <p>Globally, aquaculture has developed significantly; however, poor performance at larvae stage is still a challenge. The use of antibiotics has post-application effects in aquaculture hence the demand for eco-friendly alternatives. The <em>Lactobacillus fermentum</em> strains BCS27 and F4S8 isolated from fermented maize and cassava respectively were supplemented in six isonitrogenous (55% protein) fry diet in three different concentrations (3x10<sup>7</sup>, 6x10<sup>7</sup> and 9x10<sup>7</sup>cfu/ml/100g) with a positive (T<sub>0</sub>) and negative (AT<sub>0</sub>) controls. The strain BCS27 were included in these concentrations to give treatments LF<sub>1</sub>T<sub>1</sub>, LF<sub>1</sub>T<sub>2</sub>, LF<sub>1</sub>T<sub>3</sub> while strain F4S8 represented treatments LF<sub>2</sub>T<sub>1</sub>, LF<sub>2</sub>T<sub>2</sub>, LF<sub>2</sub>T<sub>3</sub>. Three-day old <em>Clarias gariepinus</em> larvae (0.005g) were fed to satiation for eight weeks in a completely randomized design. The highest mean weight gain (MWG) of 0.4116±0.02g and specific growth rate (SGR) of 0.9765±0.05%/day were recorded in LF<sub>1</sub>T<sub>1</sub>. Quadratic regression analysis of growth indices against microbial counts revealed that at concentration of 50.7CFU/ml the best weight gain of 0.39g was obtained. The treatment LF<sub>1</sub>T<sub>1</sub> also produced the highest protein efficiency ratio (PER) (0.007±0.0003) and nitrogen metabolism (NM) (4.86±0.23). Survival was significantly low (22.5±5.1%) in AT<sub>0</sub> while the highest value (42.3±3.18%) was recorded in LF<sub>1</sub>T<sub>1</sub>. Amongst strain F4S8, LF<sub>2</sub>T<sub>1</sub> had significantly higher (p&lt;0.05) MWG (0.4197±0.01g). The optimum treatment concentration was 62.5CFU/ml at 0.33g MWG. The treatment LF<sub>2</sub>T<sub>1</sub> also had the best PER of 0.007±0.000 while T<sub>0</sub> recorded the least value (0.003±0.0004). The highest survival (44.2±1.5%) was recorded in LF<sub>2</sub>T<sub>2</sub>. The studied<em> L. fermentum</em> strains was viable in the feed which successfully improved the performance and nutrient utilization in <em>C. gariepinus</em> larvae. Thus, it’s application in fish feed production is recommended.</p> <p><strong>Keywords:</strong> <em>Lactobacillus fermentum</em>, growth, <em>C. gariepinus</em>, fry, larvae.</p> J.C Ikwuemesi, E.K Ajani, B.O Emikpe Copyright (c) Fri, 16 Apr 2021 00:00:00 +0000 The Probiotics, <i>Lactobacillus Acidophilus</i> and <i>Saccharomyces cerevisiae</i> in Diets of <i>Clarias gariepinus</i> Improve Feed Utilization and Growth <p>The study evaluated effects of incorporating different proportions of probiotics, <em>Lactobacillus acidophilus</em> (LAC) and <em>Saccharomyces cerevisiae</em> (SAC) in diets of <em>Clarias gariepinus</em> for improved growth and feed utilization. Six isonitrogenous (34% protein) diets were compounded with varying probiotic inclusion ratios (LAC: SAC) as followed: F1 (0:25%); F2 (25:0%); F3 (15:10%); F4 (10:15%); F5 (5:20%) and F6 (12.5:12.5%). The diets were mixed, preconditioned and steam pelleted at 100oC. Fish (average weight 35.16 ± 2.32g) were stocked at 15 fish per 80-liter aquarium tank and fed the experimental diets ad libitum for 60 days. Results showed that catfish fed with F2 (25% LAC and 0% SAC) had the best feed conversion ratio of 1.72±0.04, specific growth rate, 5.00±0.24 %/day, average weight gain 19.13±0.04g, final weight 56.46±0.08g and protein efficiency ratio of 0.59±0.02. Fish fed F1 (25% SAC and 0% LAC) achieved about half the growth and nutritional parameters of those fed diet F2. Growth performance increased with increasing inclusion level of LAC. However, fish fed F6 had a better specific growth rate than other mixtures except for those in F2 group. It could be inferred that reduced inclusion of SAC seemed beneficial to catfish.</p> <p><strong>Keywords:</strong> Probiotics, lactic acid bacteria, yeast, gut microbiome, African catfish</p> U.D Enyidi Copyright (c) Fri, 16 Apr 2021 00:00:00 +0000 Physical Properties and Water Stability of Wheat and Cassava flour Binders for Fish Feed Formulation <p>The experiment assessed the binding effects and some physical properties of wheat and cassava flour binders used in fish feed formulation. Three diets were formulated using cassava, wheat and a combination of cassava and wheat flours in a ratio of 1:1 as binders. These diets were designated as Treatments 1, 2 and 3 respectively. The physical properties evaluated were pellet-ability and dustiness. Water stability test included: weight gain, sinking time/rate, relative absorption rate and absorption efficiency rate. The results showed that all treatments produced high binding potential. There were no significant differences (p&gt;0.05) in pellet-ability amongst the treatments, with values of 99.86±0.25%, 99.62±0.19% and 98.76±0.59% for Treatments 3, 2 and 1 respectively. Dustiness showed a significant difference (p&lt;0.05) amongst the treatments. Treatment 3 recorded a low value of 0.64% which was significantly difference (p&lt;0.05) from Treatments 1 and 2 while Treatment 2 had the highest value of 1.00%. The water stability test showed that Treatment 3 had the best sinking time rate of 4.33±0.04sec and sinking time index of 0.23±0.00sec<sup>-1</sup> which were significantly different (p&lt;0.05) from the other treatments. There were no significant differences (p&gt;0.05) between Treatments 2 and 3 in water stability test, but they were both significantly different (p&lt;0.05) from Treatment 1. Treatment 3 had the best water stability value of 92.04% and Treatment 1 the least with a value of 80.28%. The binders proved to be more effective when used in combination.</p> <p><strong>Keywords</strong>: Leaching, fish feed, fish farming, binders, eutrophication</p> P.C Onuoha, G Ugwumadu, D Chinonyerem, K.P Okpala-Ezennia, K.A Ogbuagu Copyright (c) Fri, 16 Apr 2021 00:00:00 +0000 Influence of Socio-Economic Factors on the Profitability of Fish Farming in Owerri North Local Government Area of Imo State <p>The study was carried out to examine the influence of socio-economic characteristics on profitability of fish farmers in Owerri North LGA of Imo State. The study considered cost incurred and returns accrued on fish production in the area. Also, the relationship between the revenue derived from fish farming and various factors affecting fish production were determined. Standard procedures were adopted in all experimental analyses. One hundred and ten (110) fish farmers were randomly selected within the study area and used for the work, and data were collected using a well-structured questionnaire. Collected data were analysed using descriptive statistics such as percentages and inferential statistics (multiple regression at p&lt;0.05) as well as cost and return analysis. Results showed that average annual income of a fish farmer was ₦6,269,886 while the profitability index was 1.89. Thus, indicating that, for every one-naira (₦1.00) investment made in fish farming in Owerri North LGA, ₦1.89 was returned to the farmer as net income. The study further showed that sex and years of farming experience were statistically significant and positively correlated (R<sup>2</sup>=0.8570; p&lt;0.05) with net farm returns. On the other hand, age of the farmer, education attainment and marital status were negatively correlated and not significant. It is therefore recommended that people should engage in fish farming in the area as it is a profitable venture.</p> <p><strong>Keywords:</strong> Cost, returns, socio-economic factors, fish farming, Owerri North</p> J.I Ukagwu, S Ohaturuonye, C Dan-Uchegbu, U Nkulo, J.O Ohakwen Copyright (c) Fri, 16 Apr 2021 00:00:00 +0000 Effects of <i>Curcuma longa</i> on Growth and Biochemical Variables of <i>Oreochromis niloticus</i> Challenged with a Consortium of Bacteria <p>This study evaluated effects of turmeric on growth and immune response of Nile tilapia. Five phytogenic feeds were formulated with varying inclusion levels of turmeric thus: F1 20 %/kg; F2 15 %/kg; F3 10 %/kg; F4 % g/kg and F5 0 %/kg. There was a commercial feed (F6) which served as the control experiment. Fish fingerlings (initial weight ca. 14.2g) were fed experimental diets for 70 days, thereafter, they were subjected to dual bacterial challenge by injecting a consortium of <em>Staphylococcus aureus, Pseudomonas aeruginosa</em> and<em> Flavobacterium columnare</em> into the culture media and then intraperitoneal injection of the bacteria into the fish muscle. Growth, nutritional performances and immunity of the fish were analyzed using standard procedure. Results showed that the relative protection levels of fish fed diets F1 to F3 were 100%, while 95.56% was obtained in group fed diet F4. A 0% mortality was recorded for fish fed diets F1 to F3, 4.4 % for those fed diet F4 and 100% for those fed diets F5 and F6. The best specific growth rate was recorded in fish fed diet F1 with the values decreasing with decrease inclusion levels of turmeric in diets. Alanine aminotransferase and aspartate aminotransferase reduced with the inclusion of turmeric. Results showed that increasing turmeric inclusion up to 20% in tilapia diet would increase growth rate and enhance immunity against bacterial diseases.</p> <p><strong>Keywords</strong>: Turmeric, phytogenic feed, O. niloticus, bacterial challenge, aquatic microbes</p> U.I Enyidi, C.P ORji Copyright (c) Fri, 16 Apr 2021 00:00:00 +0000