aquaria (e.g., captive killer whales) continues. History Whaling began in prehistoric times in coastal waters. The earliest depictions of whaling are the Neolithic Bangudae Petroglyphs in Korea, which may date back to 6000 BC. These images are the earliest evidence for whaling. Although prehistoric hunting and gathering is generally considered to have had little ecological impact, early whaling in the Arctic may have altered freshwater ecology. Early whaling affected the development of widely disparate cultures on different continents. The Basques were the first to catch whales commercially, and dominated the trade for five centuries, spreading to the far corners of the North Atlantic and even reaching the South Atlantic. The development of modern whaling techniques was spurred in the 19th century by the increase in demand for whale oil, sometimes known as "train oil", and in the 20th century by a demand for margarine and later whale meat. Many countries once had significant whaling industries, and these are covered in separate articles; for example Whaling in the Netherlands, Whaling in Scotland, and Whaling in Argentina. Canada, Iceland, Japan, Norway, Russia, South Korea, the United States and the Danish dependencies of the Faroe Islands and Greenland continue to hunt in the 21st century, and are described below. Modernity The primary species hunted are minke whales, belugas, narwhals, and pilot whales, which are some of the smallest species of whales. There are also smaller numbers killed of gray whales, sei whales, fin whales, bowhead whales, Bryde's whales, sperm whales and humpback whales. Recent scientific surveys estimate a population of 103,000 minkes in the northeast Atlantic. With respect to the populations of Antarctic minke whales, as of January 2010, the IWC states that it is "unable to provide reliable estimates at the present time" and that a "major review is underway by the Scientific Committee." Whale is used little today and modern whaling is primarily done for food: for pets, fur farms, sled dogs and humans, and for making carvings of tusks, teeth and vertebrae. Both meat and blubber (muktuk) are eaten from narwhals, belugas and bowheads. From commercially hunted minkes, meat is eaten by humans or animals, and blubber is rendered down mostly to cheap industrial products such as animal feed or, in Iceland, as a fuel supplement for whaling ships. International cooperation on whaling regulation began in 1931 and culminated in the signing of the International Convention for the Regulation of