Bransfield Strait or Fleet Sea (Spanish: Estrecho de Bransfield, Mar de la Flota) is a body of water about 100 kilometres (60 mi) wide extending for 300 miles (500 km) in a general northeast – southwest direction between the South Shetland Islands and the Antarctic Peninsula.

On 23 November 2007, the MS Explorer struck an iceberg and sank in the strait; all 154 passengers were rescued and no injuries were reported.

[3] Thermophiles found on the seafloor outside Orca Seamount may indicate that thermal waters of Orca Seamount may travel laterally through geological structures or that currents bring in thermal water from Deception Island, an active volcano.

[5] An area of relatively shallow marine waters of about 1021 km2, off the western and southern coasts of Low Island, has been designated an Antarctic Specially Protected Area (ASPA 152) because it is one of only two known sites near the United States’s Palmer Station suitable for bottom trawling for fish and other benthic organisms.

Fish have been collected from the site by scientists from Palmer Station since the early 1970s, and it is recognised as an important spawning ground for several species, including Black Rockcod and Blackfin Icefish.