If I understood correct than Nozomi said she came to catch a water Pokémon and at the end of the episode said she stays there to catch one
She also said the next contest is at Hearthome and both her and Dawn will participate in it
So maybe in that contest we'll see what water Pokémon Nozomi caught? if thats must be a DP one so I think the only possible ones are Shellos or Bidoof's evolution

And after watching that episode it's even more obvious that Ash and Dawn will trade Aipom and Buizel
They used contest battle style to confuse Buizel and Buizel's battle style is really like regular/gym battles while Aipom likes contests and Nozomi already suggested in DP12 that Ash should give it to Dawn (and also they probably want to show more trades in DP to advertise Wi-Fi) and before people will start with the whole "Ash and Dawn like their Pokémon and won't trade" this is a special case since that trade will make these Pokémon to be able to do what they really want instead of forcing them to throw away their dreams