Análise oceanográfica de encalhes de pinguins-de-magalhães Spheniscus magellanicus (Forster, 1781) no litoral do estado do Rio de Janeiro

Abstract

The magellanic penguin (Spheniscus magellanicus) spends much of its life migrating in the sea. Because of this, they are regarded as marine bioindicators. They display a wide geographical distribution, ranging from 40°S to 55°S on islands and coasts of the South Atlantic Ocean and up to approximately 33°S on the coast of the Pacific Ocean. The goal of this study was to correlate the occurrences of magellanic penguin strandings on the coast of the state of Rio de Janeiro with oceanographic processes present in the study region. Receipt reports were used for stranding in 2013 and 2015. A descriptive statistical analysis was performed to visualize the months of higher frequency of these occurrences. The results of the Copernicus information base were used to generate estimates of monthly averages of temperature, zonal and meridional sea surface layer velocities, monthly average surface current fields and average monthly temperature differences of 2015 and 2013. The total annual number of strandings for both years was 119 individuals. In 2013, the month with the highest number of strandings was September, and in 2015 it was June. 2015 had warmer sea surface temperatures throughout the year compared to 2013. In both years the incidence of stranding was higher in the winter. The Brazil Current was intense throughout almost the entire 2015, while in 2013 it remained intense during the summer and spring. Although the total number of strandings in 2013 and 2015 were the same, the frequencies of those strandings over the months were totally different. When grouped seasonally, winter stands out with the highest number of penguins stranded in the two years studied. However, in 2015, the seasons of autumn and spring had a similar number of occurrences. These results indicate that the arrival of magellanic penguins in the Brazilian coast may be changing over time, and contrasts directly with the theoretical background that the arrival period is only in the winter season.