Estudo da diversidade específica acessível a pesca artesanal nas águas marinhas costeiras da Província de Sofala

Abstract

The present research studies the diversity and dominance of fishery resources accessible to artisanal fishing in the Northern and Southern regions of the Beira estuary, Sofala Province. The research is motivated by the increasing pressure on coastal ecosystems due to socio-economic development and intense human activity. The objective is to evaluate species diversity, species richness, and the distribution of species in the two regions, North and South of the estuary. A methodological approach that divides the estuary into two areas was utilized to allow for detailed comparative analysis. Using R Studio software (version 4.3.3), exploratory analysis was conducted to examine the data and identify potential issues prior to applying statistical techniques. Indices such as Shannon Diversity Index (H’), Margalef Species Richness Index (Dmg), and Pielou’s Evenness Index (J’) were calculated to measure species diversity, richness, and evenness, respectively. Additionally, the Relative Importance Index (IRI) was calculated to determine species dominance, combining the percentages of the number of individuals, weight of individuals, and frequency of species occurrence. Quantitative and statistical data analysis was performed to identify patterns and trends, particularly between the South and North strata of the estuary. Ten most abundant species were selected for detailed analysis.The results indicate that the Southern region exhibits greater species diversity and abundance, as well as a more uniform distribution compared to the Northern region. The Shannon Diversity Index (H’) was 3.712 in the South and 3.656 in the North. Pielou’s Evenness Index (J’) was 0.0013 in the South and 0.001 in the North, indicating a more uniform distribution of species in the North. Margalef Species Richness Index (Dmg) was 1851 in the South and 1360 in the North, reflecting a greater variety of species in the South. The total abundance of individuals was higher in the South, with 29,544 individuals compared to 18,478 in the North. Species such as Scomberomorus commerson and Otolithes ruber dominate, suggesting a productive and resilient ecosystem.In conclusion, species diversity and abundance are fundamental to the sustainability of artisanal fishing, providing food security and a stable economic base for local communities. The implementation of sustainable management practices and habitat conservation is recommended to ensure the health of fishery ecosystems in the Beira estuary.