Fish catches, and the influence of climatic and non-climatic factors in Lakes Chivero and Manyame, Zimbabwe

Abstract

Inland fisheries provide income, food security and nutrition and act as a labour buffer. Yet they scarcely receive consideration in water resource allocation and economic decisions. Inland peri-urban fisheries face many challenges to their sustainability such as urban encroachment, environmental degradation and climate change. This study aimed to assess the historical fish catches, species composition, and investigate the effects of climatic variability and catchment dynamics in peri-urban Lakes Chivero and Manyame in Zimbabwe. The Mann-Kendall test was used to analyse time series trends in fisheries and climatic data. Multiple regression analysis was used to assess relations between fish catches and climate data for Lakes Chivero and Manyame. Fish catches have significantly declined in Lakes Chivero and Manyame over the periods considered with a shift towards a monospecies dominance in the fish community. Peri-urban lakes are characterised by highly adapted, relatively large sized fish species which have an ability to utilise a directional environmental disturbance such as hypereutrophication. Climatic factors have significant effects in fish catches in Lake Chivero. Despite the potential negative socioeconomic consequences inferred from declining fish catches, water pollution, gross underreporting, poor recording and preservation of fisheries statistics remains a massive threat to the survival of inland peri-urban fisheries in Lakes Chivero and Manyame.

Keywords

• fish statistics
• catch per unit effort
• climate change
• pollution
• inland lakes
• poverty