Avaliação da diversidade especifica da pesca artesanal na praia de Tofo na província de Inhambane, Moçambique

Abstract

The main focus of this study was the assessment of species diversity in artisanal fishing at Tofo Beach in the Inhambane Province. Historical data spanning eight years, from 2013 to 2020, were used for this evaluation. The analysed data pertained to two fishing methods: gillnet and handline, as these are the most commonly used techniques for capturing fish resources in the study area. The region’s habitat consists of sandy and coral environments. The assessment involved various analyses, including the specific composition of catches. Approximately 263 species from 72 families were identified. Among these, the species Scomberomorus commerson exhibited greater dominance compared to other species. Subsequently, an estimation of diversity was conducted using the Shannon-Wiener Index (1948) for the assessment. It was observed that Tofo Beach exhibits greater species diversity, with a Shannon-Wiener diversity index value of 2.53, which is related to the type of substrate found at Tofo Beach. A comparative analysis of diversity estimates for the two fishing methods was performed, revealing greater species diversity for handline fishing compared to gillnet fishing. To complement the analysis of Shannon-Wiener diversity indices, the frequency of occurrence of families was calculated to verify the degree of distribution at Tofo Beach over the analysed time series. The Lethrinidae family was common, occurring in all years of the studied series except for 2020, followed by the Scombridae and Balistidae families, which were also common in 4 out of the 8 years of the studied series. It is noteworthy that of the two fishing methods analysed, handline fishing is the most important at Tofo Beach in Inhambane, followed by gillnet fishing. The estimation of biodiversity is very important as it allows the identification of priority areas for species conservation and the subsistence of fishing communities. To achieve this, it is essential to understand species distribution patterns, identify areas of greater abundance and endemism, and compare the species composition of different areas (Crisci et al. 2003).