Kujira (1952)

Short films with highly stylized and unique visuals, makes special use of color and environmental storytelling rather than explicit exposition, both also animated by a limited amount of staff leading to very personal and intimate feeling movies 

Both are short, old movies. Both have similar animation done with siluettes and both have similar feeling. 

Both are very short, few minute long movies. Both feature whale, but while in Kujira it´s about fighting whale, in Man & Whale it´s about saving it. 

Both are short, few minute long anime. Both feature part when main characters fight a whale that is trying to eat them. While Kujira is fantasy, Bavel no Hon is more for kids.