Effect of cages on water quality parameters at pearl aquatics fish farm Garuga

Abstract

Fish farming in cages is the most common technology in marine waters, practiced mostly by developed countries such as Norway, Germany, Netherlands and most of the developing countries of East and Central Africa including Uganda. However, fish farming in cages which is a commonly used technology has become an ecological threat to most agricultural organisation since cages sometimes have an effect on the quality of water which makes the study that assesses the effect of cage fish farming on the water quality important. This study sought to assess the effect of cage fish farming on the water quality at Tende bay,Garuga on Lake Victoria. The objectives which guided the study were to: determine the effect of cages on temperature and transparency and determine the effect of cages on the pH, conductivity, dissolved oxygen, ammonia, nitrite, nitrates, and phosphorous in water. The experiment comprised of four sampling sites selected at which samples were drawn from. The sampling was done along a transect as you move from the cages to open waters. The first site, A was within cages and the second site was10m from the second sampling site B. The third sampling site C, was 10meters from the second sampling site and the fourth sampling site, D was 10m from the third sampling site. These sampling points were randomly selected and marked for sampling using an anchored mark buoy.The physical and chemical water quality parameters analyzed using spearman correlation, ONE WAY- ANOVA for variations in mean, standard deviation, co-efficient of variation and Post-HOC test to show exactly where the difference in means was. My findings showed a negative relationship between temperature and D.O at p value 0.130 and r value 0.257. The findings showed that there is a negative relationship between transparency and biological oxygen demand at p value 0.44 and r value 0.588. Furthermore, my findings showed that there is a positive relationship between pH and alkalinity. This study shows that cage site has an influence on water conductivity of the fish pond. Findings of this study are in agreement with Pearson & Black (2001) who mentioned that cage site influence the parameters of water quality.