Marinha do Arvoredo Biological Reserve, Marine biological reserve on Santa Catarina coast, Brazil

The Marinha do Arvoredo Biological Reserve covers 17,104 hectares off Santa Catarina, spanning Bombinhas, Florianópolis and Governador Celso Ramos. Its archipelago is formed by Arvoredo (318.6 ha, the largest, with steep coastlines), Galés (39.7 ha, closest to the continent) and Deserta (13.2 ha), plus the São Pedro rocky outcrop. The islands rest on the continental shelf, with Precambrian crystalline rock shorelines and depths of 5 to 25 metres, rarely beyond 30.

The Brazilian Federal Government established this marine sanctuary in 1990 to protect the natural resources and marine life of the Santa Catarina coast. The creation of the reserve represented a major step in safeguarding this ecologically important ocean region from human activities.

The reserve is closed to visitors, so its cultural history is not accessible on foot. The islands were a traditional recreational diving destination in southern Brazil from the 1980s until 2000, when the SNUC law closed the reserve to diving. Dive operators now work only south of Arvoredo Island, outside the reserve limits, with regular departures from Florianópolis and Bombinhas.

The reserve is closed to visitors: as a strict biological reserve it admits no public entry, and diving inside its limits has been banned since 2000 under the SNUC law. Dive operators from Florianópolis and Bombinhas now work only along the south shore of Arvoredo Island, which lies outside the reserve boundary.

The reserve sits in a transition zone where tropical and temperate ocean species meet, shaped by two major currents flowing in opposite directions. This collision of different water masses creates an unusual mix of marine life that appears nowhere else in the region.