Study shows that Selvagem Grande is home to a colony of 39,000 pairs of shearwaters

Selvagens, in the Madeira archipelago, is home to the largest colony of shearwaters in the Atlantic, with around 39,000 pairs on a single island, according to a study coordinated by Portuguese researchers, indicating that the annual growth rate is 1.45%.

It is interesting to note that the number of nests has increased more rapidly in areas where there has been an expansion of shrub cover, under which shearwaters can nest, which is a result of the recovery of vegetation in Selvagem Grande, following the eradication of rabbits and mice in 2002, says Paulo Catry.

The researcher from MARE – Center for Marine and Environmental Sciences, at Ispa – University Institute, is one of the study coordinators, together with José Pedro Granadeiro, from the Center for Ecology, Evolution and Environmental Changes (CE3C), at the Faculty of Sciences of the University of Lisbon.

The study, published by the University of Cambridge in the United Kingdom on January 20, reveals that the population of shearwaters (Calonectris borealis) in Selvagens has grown at an annual rate of 1.45% since 2009.

According to researchers, shearwaters, like most pelagic birds, face several threats, including accidental capture in fishing gear, collision with sources of light pollution, predators introduced to islands, marine pollution, especially by plastics, and the decrease in ocean productivity linked to climate change.

However, despite the threats, “the growth of this important population of shearwaters shows that the conservation efforts undertaken, namely the full protection of Selvagens and its management by the Madeira Forestry and Nature Conservation Institute, have had very positive impacts”, highlights Paulo Catry.

The Selvagens, a subarchipelago of Madeira located about 300 kilometres south of Funchal, made up of two main islands and several islets, constitutes the southernmost territory of Portugal, having been classified as a nature reserve in 1971.

In March 2022, the reserve was expanded from 92 to 2,677 square kilometers, in an area of ​​12 nautical miles around the islands, in which fishing and any other extractive activity is prohibited, becoming the largest marine area with full protection in the North Atlantic.

However, in July 2024, the Regional Secretariat for Agriculture, Fisheries and Environment revealed that it had temporarily authorized the capture of skipjack fish in the reserve for the purposes of research and monitoring of the species.

From Jornal Madeira