Island of the Giant Pokémon

S1, E17: As our heroes and Team Rocket beat the odds by surviving the sinking ship, they are dragged into another perilous situation when they are attacked by the Atrocious Pokémon, Gyarados. One Gyarados is soon joined by many, and Ash, friends, and foes are swept up in a monstrous Dragon Rage that sets them down in various places around an island. Ash loses Pikachu and the Poké Balls containing Charmander, Squirtle, and Bulbasaur. Jessie and James from Team Rocket, who land in another remote part of the island, also lose their Pokémon. Thus both Pokémon and Trainers are left searching for each other on this strange island, inhabited by gigantic Pokémon. Where could this island be?