Effects of environmental variables on Magellanic penguin (Spheniscus magellanicus) strandings in southeastern Brazil
Abstract The species Spheniscus magellanicus, popularly known as the Magellanic penguin, is the most common penguin species in the Brazilian coast. Its strandings are related to several causes, ranging from fishing interaction, diseases, anthropic pressures, to the occurrence of storms and extreme weather events. These different phenomena can affect the species’ search for food, their physical conditioning and survival, and can lead individuals to death. The objective of the present study is to evaluate the effects of environmental variables on the strandings of Magellanic penguins that occurred at Ilha Comprida, in the southern coast of Sao Paulo State, Brazil, between 1998 and 2016. Strandings data were collected at the monthly frequency using beach monitoring techniques. Monthly averages of the environmental variables wave height (WH), sea level pressure (SLP), wind intensity (WI) and sea surface temperature (SST) were also obtained from various sources. The methodology applied here consisted of a preliminary correlation analysis and a subsequent multiple regression analysis using Generalized Linear Models (GLM) with binomial distribution. The results demonstrated that there is a relationship between the combined effect of the increase in SLP and the decrease in SST with the number of strandings. The strandings, as expected, were also associated with the migratory period of the species and their occurrence in the study area. The results provided new knowledge about the factors, mainly non-anthropogenic, that can lead to the stranding of Magellanic penguins on the study area, contributing to future initiatives for animal conservation and preservation.