As of Friday (10.04.2015), four Japanese whaling ships are on the way into the Pacific. By the end of this May, they may have killed up to 51 minke whales. Officials argue that the hunt is necessary for research into the effects whales have on coastal fishing. Just one year ago, the International Court of Justice in The Hague banned Japan from continuing its whale hunt.

The hunt for the endangered sea mammals has been outlawed since 1986 - but Norwegian, Icelandic and Japanese companies continue to hunt whales. The Japanese, in particular, argue that their whaling program is conducted for purposes of scientific research. But Japan is also hunting ever less and less: this past January, two whaling ships set out to counting whale and take tissue samples.

For 20 years, Australia tried unsuccessfully to persuade Japan to stop its whaling program through diplomatic channels - and finally took the country to court in 2013. In Late March 2014, the International Court of Justice (ICJ) in The Hague ruled Japan's whaling program is not for scientific purposes, and ordered a temporary stay.

Whale stocks have stabilized since the ban was implemented 27 years ago. However, more than half of the 13 great whale species are classified as endangered or vulnerable. This includes blue whales, fin whales, sei whales, southern right whales and sperm whales. Whales can grow to be 33 meters (108 feet) long and weigh 190 tonnes (209 tons) - making them the largest animals on Earth.

Hunted down in the name of science, the whales' meat is later sold to stores and specialty restaurants. The Tokyo-based Institute of Cetacean Research was founded exactly one year after the 1986 moratorium issued by the International Whaling Commission.

Whale meat has long been on dinner plates in Japan. Especially after World War II, the population of the island nation depended on whale meat. Schools and canteens cherished it because it was cheaper than beef. But times have changed - and now whale meat accounts for only 1 percent of meat consumed in Japan.

You can find up to 7,000 tons of whale meat stored in Japanese warehouses. Due to a lack of buyers, a Japanese firm had fin whale meat processed into dog food. However, protests by international animal rights groups made the company announce that it was discontinuing production of the dog treats.

Despite all this, many Japanese still support whale hunting and decry the actions of environmental campaigners like Greenpeace as eco-terrorism. Japan's government has refused to give in to international pressure, and has been subsidizing whaling programs since 1988 with around 800 million yen (6.3 million euros) a year.

Iceland and Norway also have whaling programs in defiance of the ban. Both countries lodged objections to the moratorium, and don't feel the need to abide by it.

Indigenous people such as the Chukchi in Russia or the Inuit in Canada are officially entitled to hunt whales as long as they don't do it for commercial purposes. For these people, whaling is a tradition that goes back hundreds of years. The sea mammals provide them with meat, oil and bones. Every part of the animal is used.

Environmental groups played an important role in issuance of the whaling ban. For decades, they led spectacular campaigns to draw the world's attention to the issue of whale hunting. The organization Sea Shepherd is known for its controversial and aggressive approach to protecting the giants of the sea.

Many countries that used to have whaling programs are now in the business of whale watching. Some of the whale watchers in Japan and Norway are former whale hunters who now share their knowledge with tourists. Also in Japan, an ever-increasing number of citizens would rather see these animals in the wild than on their dinner plates.

A whaling fleet of three Japanese ships departed from the country's port of Shimonoseki earlier this month. They're heading toward Antarctic waters for the annual whale hunt. Japan is planning to kill almost 1,000 whales during the southern hemisphere summer. Japan maintains its whale hunts are for scientific purposes, but much of the meat ends up in restaurants and markets.

The two whaling ships and a surveillance vessel that left port on December 7 were set to join the factory ship, Nisshin Maru, pictured. Together they aim to hunt up to 935 Antarctic minke whales and up to 50 fin whales before the season ends in March.

Their whaling fleet's departure date was kept secret, Japan's Kyodo News reported, due to concern from the Japanese Fisheries Agency that anti-whaling groups like Sea Shepherd, which are known for daring maritime protests, would attempt to disrupt their departure.

Last whaling season, Japan's whale catch fell to a record low of 103 minke whales. While stormy weather played a part, high-seas intervention by Sea Shepherd activists determined to disrupt the whaling also played a big role. Methods used by the activists include throwing stink bombs at the whalers. The whaling ships use jets of water to keep the protestors away.

For the past few years, environmental groups like Greenpeace and Sea Shepherd have been actively pursuing Japan's whaling fleet in the frigid waters of the Southern Ocean. Their protests have drawn international attention to the issue and condemnation from whalers, who say they are putting people’s lives in danger.

Commercial hunting for the giant sea mammals has been banned since 1986. But the rules allow whaling for scientific and research purposes. This is how Japan is able to continue catching hundreds of whales each season, to the outrage of activists and other nations who want to see hunting stopped. Though whale numbers have stabilized since the ban, several species remain in danger.

Eating whale meat has been part of Japanese life for hundreds of years. After World War II, when other meat was expensive, whale became a big part of Japan's diet. However, whale now accounts for only a tiny portion of the meat sold in Japan, and there is a strong movement in the country opposed to whaling.

While some activists like the Sea Shepherd Conservation Society's Paul Watson have faced courts for protests, nations have also taken eachother to court. Australia has taken Japan to the United Nations’ International Court of Justice, saying Japan is exploiting the international commercial whaling law loophole. Australia is hoping the court will ban Japan’s hunting in time for this whaling season.