Estudo do efeito da variação ambiental na distribuição ecológica dos pequenos peixes pelágicos nas águas marinhas territoriais de Moçambique

Abstract

Which environmental variables determine the distribution and abundance of small pelagic fish in Mozambican waters? To address this question, data from scientific surveys conducted in 2018 and 2023 were analyzed using Principal Component Analysis (PCA), integrating environmental gradients (sea surface temperature, salinity, dissolved oxygen, chlorophyll-a, net primary productivity, depth, and latitude) with the abundance of four representative species: Decapterus russelli, Leiognathus lineolatus, Myctophidae, and Thryssa vitrirostris. Findings revealed that species distribution is strongly influenced by environmental conditions. Myctophidae were consistently associated with deeper waters, confirming their mesopelagic character. Thryssa vitrirostris was linked to surface, productive, and oxygen-rich waters, whereas D. russelli was associated with cooler and less oxygenated environments. L. lineolatus was correlated with nutrient-rich coastal areas, influenced by chlorophyll-a and primary productivity. Temporal comparisons between 2018 and 2023 showed shifts in community structure, highlighting the sensitivity of small pelagics to environmental fluctuations and possible climatic changes. Overall, the study concludes that salinity, temperature, oxygen, chlorophyll-a, primary productivity, and depth are the main drivers shaping small pelagic fish ecology in the Mozambique Channel, providing crucial evidence for sustainable fisheries management.