I went to basilo blubber gathering to Crystal Isles tropical area with a desmo and a great shotgun. There are not too deep waters.

I really found out the laziest and easiest method, and you need to do it at night. I don't like to be in water ingame, and don't have any aquatic creature to battle with them face to face...

So I just turn on the desmo's night vision mode, looking after the basilos, and shot them from the air. When I start shooting, all the mantas flee away, so when the basilo is dead, I can just swim to it for it's loot.

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