Station the largest of which was still named B-15A (now measuring approximately ). Three additional pieces were named B-15P, B-15M, and B-15N. Iceberg B-15A then moved farther up north and broke up into more pieces. These were spotted by air force fisheries patrol on 3 November 2006. On 21 November 2006 several large pieces were seen just off the coast of Timaru, New Zealand—the largest measured about , rising from the surface of the ocean. As of 2018, four pieces remain that are large enough to be tracked by the National Ice Center (at least ). One piece, B-15Z, measures . It was located in the southern Atlantic Ocean, about northwest of South Georgia Island. As it continues its move northward, the speed of melt increases. Most icebergs do not last long this far north. By 2020, only two pieces remained large enough to track. B-15aa – a direct remnant of B-15z – was drifting to the east of the island of South Georgia, in the south Atlantic Ocean. B-15ab remained among sea ice along the coast of Antarctica south of Africa. In 2021, B-15ab became the last fragment to remain on the US National Ice Center list of tracked icebergs, still grounded off the coast of Antarctica. Effects on Antarctic ecology On 29 January 2001, researchers from the University of Chicago and the University of Wisconsin installed weather and Global Positioning System instruments on Iceberg B-15A. It was the first time an iceberg had been monitored in this way. The data gathered led to an unprecedented understanding of how giant icebergs make their way through the waters of Antarctica and beyond. Iceberg B-15A collided with Drygalski Ice Tongue on 10 April 2005, breaking off an section of the ice tongue. Antarctic maps needed to be redrawn. B-15A prevented ocean currents and winds from assisting in the 2004–2005 summer break-up of the sea ice in McMurdo Sound, and was an obstacle to the annual resupply ships to three research stations. The floe was expected to cause a catastrophic decline in the population of Adélie penguins, as it added considerable distances which parent penguins must travel back from the sea to their chicks. Weddell seals and skuas are also inhabitants of McMurdo Sound and their populations may have been affected as well. On 21 October 2005 a large storm in the Gulf of Alaska generated a trans-Pacific ocean swell that may