| dc.description.abstract | In recognition of the importance of the aquaculture sector in Kenya, the government in
the year 2008 increased its investment into the sector through Economic Stimulus
Program (ESP). In executing the project, 200, 300 and 100 fish ponds were constructed
per constituency in the first, second and final phase respectively. This unprecedent
increase in aquaculture investment may result to increased production of fish and changes
in water quality to the environment. Pollution of water resources by pond effluents is
mainly the most complaint, and this concern has attracted the greatest amount of official
attention in most countries. The characterization of fish farm effluents and the
quantification of the impact they have on the environment will provide the much needed
information and data for decision makers to formulate the necessary policies for
safeguarding the environment.
As yet, the impact of the increased investment on environmental water quality and socio
economic benefits remains to be evaluated. This study therefore determined the influence
of increased aquaculture investments on water quality and economic benefits in Central
Kenya using Gatundu South Constituency as a case in point.
The study determined the following in the study area: water quality parameters in the
main rivers used as source of water for fish farming; changes in water quality due to
effluent discharge in rivers; water quality parameters in the ponds and the socioeconomic
impact of ESP fish farming project. Sampling of water was done during the
month of January and February 2014. Water quality data sampled from the rivers and
ponds included: dissolved oxygen (DO), pH, water temperature, salinity, Nitrate- Nitrogen concentration (NO3-N) and Ortho-phosphate concentration. (PO4-P) Survey
data on the socio-economic benefits were collected in three areas in Gatundu South using
questionnaires. Water quality data were presented as means and spatial differences
analyzed using One-Way ANOVA. Frequency distribution and chi-square were used to
analyze the socio-economic data. The results of water quality analysis indicated that most
of the parameters analyzed were within the recommended range of water quality for most
aquatic organisms.
There were significant differences in all the water quality parameters analyzed in the
three rivers except for NO3-N, One-Way ANOVA; F = 0.624, df = 2, 6, P = 0.567). The
overall concentration of the NO3-N ranged from 0.66 to 0.70 mg/l. ( p < 0.05) reflecting
variations in the location of the rivers. In the ponds, water quality parameters reflected
low values of DO, and pH, with slightly higher values of salinity, NO3-N concentration,
and PO4-P concentration. In areas of effluent discharge significantly (One-Way ANOVA,
(p< 0.05) lower DO, pH and higher salinity, NO3-N concentration, and PO4-P
concentration were recorded reflecting water quality effects of the effluents in the
riverine waters. It was also noted that fish farms effluent contained pollutants that can
affect water quality, but the pollutants magnitudes were within the NEMA water quality
standards of effluent discharge were suspended solids is expected to be 30mg/l maximum
and nitrate- 100mg/l maximum. The values were impacted more for farmers within the
ESP programmes and this can be attributed to readily available inputs which they were
not paying for, hence tended to misuse them.
Because the rivers in Gatundu serves as a source of water supply for drinking, washing,
fishing and swimming, impacts of pond water discharge into natural systems should be closely monitored in order to avoid adverse effects like localised eutrophication and a
change in the trophic structure.
There was a significant difference in all socio-demographic variables of the respondents
who participated in this study. Also it was evident that farmers who participated in the
Economic Stimulus Programme (ESP) had lower fish production cycles, higher
production volumes and revenues and therefore resulted to higher margins compared to
farmers without ESP support. | en_US |
