Seasonal changes in the abundance of benthic macroinvertebrates and physico-chemical condition of Moussa Stream, Bida Nigeria, were studied monthly from January to August 2017. Macroinvertebrates were sampled using modified kick sampling techniques. Three different sampling stations were selected along the course of the Stream. The results from the stream showed that water temperature (24.9-27.50C), Depth (14.7-45.8cm), Flow velocity (0.14-0.23m/s), Biochemical oxygen demand (2.0-7.0mg/L), pH (6.33-8.6), Conductivity (20-63μ/cm), Alkalinity (8-30mg/L), Turbidity (61-285NTU), Nitrate (0.87-3.85mg/L) and Phosphate (0.31-1.01mg/L) were within the maximum permissible limit (WHO, SON) except Dissolved oxygen (3.1-10mg/L). Most of the parameters investigated with the exception of depth and flow velocity showed no significant difference (p>0.05) among all the sampling stations. Temperature, depth and flow velocity showed no significant differences with season. pH, DO, BOD5, Turbidity, Conductivity, Alkalinity, Nitrate, and Phosphate were significantly higher during wet season. A total of 471 individuals from 30 species and 20 families of invertebrates were recorded. The overall macroinvertebrates recorded from station 1, 2 and 3 were 166(35.24%), 149(31.63%) and 156(33.12%). Overall, there was significant difference (P<0.05) in number of individuals among the sampling stations. The abundance according to the Orders revealed that Coleopterans, Odonata and Hemipterans were the most common groups encountered. Ephemeroptera Diptera, Mollusca and Oligochaeta were sparingly found in all stations. The percentage and total number of individuals of macroinvertebrates recorded during the study period shows 67.09% (316 individuals) in dry season and the remaining 32.90% (155 individuals) were recorded in rainy season. CCA result correlated positively between species abundances and measured environmental variables. Low density of pollution sensitive macro invertebrates groups and the deteriorating water quality were implications of pollution stress caused by anthropogenic activities. Key words: seasonal changes, macroinvertebrates, stream, Bida.
Aquaculture is prone to pH fluctuations depending on dominating microbial pathway in the management. The present study takes advantage of the influence of pH in changing the properties of charcoal to condition the pH and improve nutrient removal. Two Synthetic aquaculture wastewaters of 100 mg/L TAN were designed to test the pathway's nutrient removal and pH stability. Glucose at 15 C/N was added to one wastewater, favoring heterotrophic pathway. The other was free of organic carbon, favoring autotrophic pathway. Powdered charcoal was added to each pathway at 0.5, 1.0, 2.0, and 4.0% (charcoal weight/volume of media) compared to the 0 % group without charcoal. The result revealed that as charcoal percentages increase, the pH shifts towards stabilization and improves nutrient removal (<i>p</i> ≤ 0.05). At 4.0% charcoal, the pH was stabilized at 6.0 – 7.5 in heterotrophic and 7.5 – 7.9 in autotrophic pathways, which are within the optimum range for the survival of aquatic organisms, corresponding to the removal efficiency of TAN (99.96 and 50 %), and phosphate (55 and 17 %) within 6 days. Hence, for every 100 mg/L of TAN in wastewater, 4.0% of the wastewater volume as charcoal could stabilize pH and improve microbial nutrient removal.
Sticky layer of Clarias gariepinus eggs cause the clumping of eggs immediately after fertilization, this create low oxygen, and increase pathogenic infection, thereby reducing fertilization and hatching rate hence reduces in mass production of C. gariepinus seed. Although various substances are use in the removal of the sticky layer, no information is available about the use of watermelon. Therefore, the present study, aim in exploring the potential of using watermelon in removing the sticky layer of C. gariepinus to enhance production. Fertilized eggs were treated with watermelon juice (T1) for comparison with 14 g L-1 milk solution (T2 as de-adhesion reference) and water as control (T0 as adhesion reference). The treatments were agitated with aeration for 30 minutes, rinsed with water, and poured on respective netted hatching trough, with water recirculation for incubation at 27 0C for 24 h period. Except for T0, no clumping of eggs was observed in the remaining groups. Slight variation in attaining a developmental stage among eggs was observed in eggs treated with watermelon. Hatching and survival rate in T2 are higher than T1 and T0 (P<0.05). However, watermelon indicated the potential, as it removed the sticky layer while maintaining hatching and survival rate as in the control (T0) (P>0.05), more should be explored before adoption of watermelon for de-adhesion and incubation of C. gariepinus eggs.
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