Effect of artisanal fishing and water pollution on the stock of Bagrid catfish (Bagrus meridionalis) in the northern part of Lake Nyasa/Niassa/Malawi in Tanzania: An insight from Nyasa district
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Date
2026-01
Journal Title
Journal ISSN
Volume Title
Publisher
Elsevier
Abstract
The critically endangered Bagrus meridionalis is one of the large fish species endemic to Lake
Nyasa/Niassa/Malawi. Its population from the southern part of the lake, in Malawi and
Mozambique, has declined by over 90 % within 10 years from 2006 to 2016 due to over-
harvesting. Despite that less is known from the northern part of the lake in Tanzania where
studies on B. meridionalis population dynamics and trends are conspicuously missing. This is
affecting effective monitoring and sustainable management of the species in this part of the lake.
The lake is also under the influence of unsustainable agricultural practices in the lake basin which
are thought to pollute the lake. However, it is also not known how this has affected the growth
and survival of the fish in the lake. We, therefore, investigated the effect of artisanal fishing and
anthropogenic pollution on the status of the stock of B. meridionalis in the northern part of Lake
Nyasa/Niassa/Malawi in Tanzania using the catch per unit effort technique, length-frequency
distribution, and relative condition factor. We sampled water and fish, and measured fish stan-
dard lengths, weights, and levels of water physical-chemical variables. We found that the stock
B. meridionalis population in the northern part of Lake Nyasa/Niassa/Malawi is very low and is
experiencing recruitment overfishing with most of the fish being caught while immature. Despite
this, the caught fishes had good body condition indicating that they are surviving in a favorable
ecological environment. Urgent mitigation measures are therefore required to halt overfishing to
safeguard community livelihood and the endangered B. meridionalis
Sustainable Development Goals
1: No Poverty
2: Zero Hunger
6: Clean Water and Sanitation
14: Life Below Water
Keywords
Artisanal fishing, Condition factor, Critically endangered species, Kampango, Length at first maturity, Pollution