Each game features 135 new Pokémon species, and pre-recorded data for each of them, plus the 251 Pokémon of previous generations.
Also, you don't need to catch all of the Pokemon to fill your Pokedex, all you need to do is see them.
Here's a website that shows you where to find each Pokemon in Sapphire, Ruby, and Emerald :
Lloyd.truepath.com
I think you need to see them all.
1 chimchar... or as many as you want if you go to pal park that is open when you finish the pokedex!
You can do many things after getting the National Pokedex. You can find the Ruby and the Sapphire, give them to Celio in One Island's PKMN Center and trade with Ruby/Sapphire/XD/Colosseum. You can visit the rest of the Sevii Islands, find pokemon not native to Kanto, and much more.
Many people think that after you beat the Pokemon league and your rival, you completed the game. To finish the game totally, get every Pokemon in the kanto and national pokedex and beat the Pokemon league. It's a real challenge!
You need to finish first the Pokedex. Then I think Professor Oak will give you.
There are 493 Pokemon in the current National Pokedex.
There are many Pokemon you catch that are similar in sapphire and emerald but there are many Pokemon emerald can only get and not sapphire.
you need 200 Pokemon to fill the whole pokedex
all of them in the regional pokedex
On red, blue, yellow, ruby, sapphire, emerald, firered, and leafgreen 491 On Diamond pearl and Platinum 493
Same as PokemonPearl, 151 is the max number of Pokemon in the starter pokedex.
you need 150 Pokemon to get the national pokedex