The annual dolphin hunt in western Japan that began Monday despite stringent opposition from conservationists, ended Tuesday. The U.S. ambassador to Japan, Caroline Kennedy, expressed her deep concern over the traditional practice of killing dolphins in Taiji, in the Wakayam region.

Every year the fishermen gather hundreds of dolphins into a cove, select some for sale to marine parks, release some into the sea and kill the rest for meat, reported Reuters.

Kennedy said the U.S government opposes the 'inhumane' practice of dolphin hunting and killing.

Deeply concerned by inhumaneness of drive hunt dolphin killing. USG opposes drive hunt fisheries.

Defending the traditional practice, Chief Cabinet Secretary Yoshihide Suga said at a news conference on Monday that the mammals were an important water resource for the fishermen of that region. "Dolphin fishing is one of traditional fishing forms of our country and is carried out appropriately in accordance with the law. Dolphin is not covered by the International Whaling Commission control and it's controlled under responsibility of each country, "reported CNN.

According to the Sea Shepherd Conservation Society, an animal rights protection groups, over 250 bottlenose dolphins were rounded up this year for the hunt. Melissa Sehgal, a Sea Shepherd activist,said that these dolphins take around 20 to 30 minutes to die as they bleed and suffocate during the killing, reported Reuters.

The dolphin hunt attracted international attention after the 2009 release of an Oscar-winning documentary 'The Cove.' Directed by former National Geographic photographer Louis Psihoyos, the documentary showed the struggle of eco-activists with Japanese police and fishermen to obtain access to the location of the hunt.

The movie was heavily criticized in Japan with some groups saying it was 'anti-Japanese' and an insult to traditional culture.