is one piece episode 583 filler?

In the Ice Lands, inside the mysterious facility, Sanji's group stares in awe as they look at the children in front of them, while the children look like they are scared of the Straw Hats. Sanji asks who the children are, and Nami wonders if this is the island's day care.

Franky mentions their size and compares them to giants, but Nami points out that some of the children aren't as big as the others. Sanji then points out that it may be a multi-racial nursery, and Nami notices that no adults are around. a child then asks who they are, and a little girl says that she doesn't know any of them.