User blog comment:Schizophrenic Psycho/Noah is Arlong's Brother/@comment-1908942-20101220010111/@comment-1595565-20101220021442

If that's so, then the group must have formed some time during the timeskip, as all other supernova crews were shown in the New World. If he had challenged another supernova (Kid and Hawkins come to mind) the supernova probably would have trounced him and he wouldn't be around for the straw hats. So they're recent.