Influência das variáveis ambientais no habitat favorável da agregação da Saurida undosquamis no Canal de Mozambique

Abstract

This study's main objective was to analyze the influence of environmental variables in favorable habitat for the aggregation of Saurida undosquamis in the Mozambique Channel (CM). The research was carried out using catch data, obtained from the Mozambique Oceanographic Institute (InOM), collected through bottom trawling, in around 164 stations on the scientific cruise Dr. Fridjof Nansen, during the months of May and June 2018 and in months of February and March 2023. Data on environmental variables were obtained from the MyOcean-Copernicus EU consortium (CMEMS;) website in netCDF format, and were extracted for each trawling station (longitude and latitude) and fishing date (year, month, day and time) using specific codes in the R program, version 4.3.1. The generalized additive model (GAM) adjusted to the Gaussian family was used to model relationships between the species' biomass, environmental and spatio-temporal variables, that is, to predict the favorable habitat based on oceanographic parameters. The quality of the predictive model of the species' aggregation habitat was adequate, that is, the explained deviation of the model ~98%, the Pearson correlation ~98%, RMSE ~3% and the Shoener similarity index ~97%. The model illustrated that the favorable habitat with the greatest biomass aggregation is located at latitudes 16ºS-24ºS, characterized by waters whose salinity varies between 30-35 gKg-1, temperatures < 27ºC; depth between 200-400m, currents almost stationary or moving towards the south and productivity with chlorophyll concentration between 0.1 – 0.5 mgKg-1. This study provides important tools for the conservation and management of Saurida undosquamis in the Mozambique Channel. Knowledge of S. undosquamis biomass aggregation areas in marine habitats is crucial for the development of sustainable management strategies and the implementation of effective conservation measures.