Fish productivity response to water quality variations: A case study of nyumba ya mungu dam, in pangani water basin, Tanzania
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Date
2023
Journal Title
Journal ISSN
Volume Title
Publisher
Hindawi
Abstract
Fish habitat degradation, such as water pollution due to the rapid expansion of incompatible land uses, is one of the noteworthy
challenges to freshwater ecosystems. Elevated contents of nutrients and contaminants in water are some of the imperative
challenges. Tis research was conducted to investigate the link between water qualities and fsh productivity in the Nyumba ya
Mungu Dam, whose fshery potential had decreased by 95% between 1972 and 2018. Physicochemical characteristics, namely,
temperature, pH, dissolved oxygen (DO), turbidity, total nitrogen, total phosphorus, chlorophyll a, and the water depth of fshing
net location, were assessed following standard procedure. Fish catches per unit efort representing fsh biomass/productivity were
monitored for twelve months from January to December 2019. Pearson’s correlation analysis indicated that fsh catch per unit
efort was positively and signifcantly correlated with turbidity (r = 0.461, P < 0.01) and TP (r = 0.405, P < 0.01). Stepwise multiple
regression model results indicated that turbidity, dissolved oxygen, and the depth of the fshing net location are the statistically
signifcant predictors of fsh catch per unit efort which represented fsh biomass. Findings further indicated that the model
combining turbidity and dissolved oxygen predicted a 24% change in fsh catch per unit efort, whereas turbidity, dissolved
oxygen, and the depth of fshing net location contributed a 28.9% change in fsh catch per unit efort. In conclusion, fsh
productivity in the NMD is limited by organic matter availability and nutrient levels that cause algae bloom occurrence. Turbidity
is an indicator of organic matter availability and the efect of algae bloom on fsh productivity. Infow of nutrients to the dam
nourishes the algae biomass, thus creating vicious cycles on fsh productivity as fsh species in the dam failed to take advantage of
high primary production by algae.
Description
Journal article
Keywords
Fish, Pangani Water Basin, Water Quality