is one piece episode 491 filler?

In West Blue, a village - Lascamp - was being attacked. The Marines already have their hands full with the surge of piracy after the war at Marineford.

Since not all information was divulged, some of the Marines were wondering how the fall of Whitebeard and a victory of the Marines would lead to an increase of pirates flooding the seas. Whereas, a few days after the war, Foodvalten Island in the New World is being attacked.

The island was under Whitebeard's territory however, since Whitebeard died in the war, the island became vulnerable.