Evolution of cetaceans decreasing. Other historical climate events can be correlated and matched with the genome history of the Yangtze River dolphin as well. This shows how global and local climate change can drastically affect a genome, leading to changes in fitness, survival, and evolution of a species. The European population of common dolphins ("Delphinus delphis") in the Mediterranean have differentiated into two types: eastern and western. According to a 2012 study, this seems to be due to a recent bottleneck as well, which drastically decreased the size of the eastern Mediterranean population. Also, the lack of population structure between the western and
USS Delphinus (AF-24) at Manila in January 1946, "Delphinus" sailed for the west coast, arriving at San Francisco, California, 23 February. For a brief period she carried cargo along the west coast and to Pearl Harbor, then sailed to New Orleans, Louisiana. "Delphinus" was decommissioned on 8 May 1946 in New Orleans, and was delivered to the War Shipping Administration the same day. USS Delphinus (AF-24) USS Delphinus (AF-24) was built in 1915 as by Workman Clark and Co., Ltd., Belfast, Northern Ireland; acquired by the U.S. Navy 11 August 1942; and commissioned the same day as "San Mateo", Lieutenant O. M. Mikkelsen,