The Great Marsh (Japanese: だいしつげんGreat Marsh) is an area located in Pastoria City. It is Sinnoh's Safari Zone and contains some Pokémon that cannot be found anywhere else in Sinnoh. It is filled with marshy areas, which, unlike normal marsh tiles, have tall grass which are inhabited by wild Pokémon.
Much like other Pokémon preserves in Kanto and Hoenn, the Great Marsh features a Safari Game in which Trainers pay $500 for 30 Safari Balls and a limited number of steps (500) to catch all the Pokémon they can.
The mechanics are similar to other Safari Zones: when a wild Pokémon appears, the player may not send out any Pokémon to battle it, but must instead try to catch the Pokémon without harming it. The wild Pokémon may choose to flee the battle at any time, thus, catching a Pokémon in the Great Marsh requires mainly luck.
There are four options shown in the battle screen:
Throw a Safari Ball - Throws a Safari Ball in possibility of capture. It is much the same as throwing a Poké Ball in an average Pokémon battle.
Throw mud - Throwing Mud makes a Pokémon easier to catch, but makes it more likely to flee from battle
Throw bait - Throwing Bait does the reverse of throwing Mud, making a Pokémon less likely to run but harder to catch.
Run from battle - Like in an average Pokémon battle, running away from a Pokémon will cause the battle to end.
Similar to the issue in Pal Park, if the player has an Arceus in the front of their party, holding a Plate, and initiates a battle, the game will freeze.
The area was redesigned in Pokémon Platinum to feature slightly upgraded graphics that allow the player to distinguish between deep and shallow mud. The park is still divided into six areas, but the individual areas have slightly different layouts.
Changing Pokémon
Using the binoculars to spot Pokémon
Some Pokémon will not always appear in the Marsh. Each day, the Pokémon will change, therefore, to get a new set, players must wait a day. These Pokémon will appear randomly in one of the six areas, some may not appear for a while, while others appear several days in a row or in multiple areas on the same day. Some may not appear until after getting the National Pokédex. The only way to tell which changing Pokémon is available in the areas for the day is to use the lookout upstairs from the entrance. Mixing records also changes the changing Pokémon of the day in the Great Marsh so all players mixing records have the same Pokémon on the same day.
In order to find out what Pokémon are going to be in each area daily, the player is able to walk up to the second floor in the lobby, and use the binoculars and look out onto the marsh. For $100 players can get a brief glimpse of the Great Marsh showing certain Pokémon in certain areas of the marsh. In each slide, a part of the park will appear with a Pokémon in the center of the slide that can be found in that area.
Details
As with previous Safari Zones, Pokémon are made easier and harder to catch by modifying their catch rates. An escape rate is also given for each Pokémon that appear in the Great Marsh. The escape rates for Pokémon are the same for all Generation IV games, except that those who do not appear in the Great Marsh or the Johto Safari Zone do not have their escape rates defined in the relevant games.
At the start of an encounter, both rates are set to their species defaults. Throwing Bait will lower the escape rate by one stage, but will also have a 90% chance of lowering the catch rate by one stage. Conversely, throwing Mud will raise the catch rate by one stage, but will also have a 90% chance of raising the escape rate by one stage. Stages for catch rates and escape rates work identically to stat stages: they may not be raised above +6 or below -6, where 0 is the starting stage. The stage multipliers applied to the catch rates and escape rates are also identical to that of stat stages.
At the end of each turn, a random number between 0 and 255 is generated, and if it is less than the modified stat stage, the Pokémon escapes.
This section is incomplete. Please feel free to edit this section to add missing information and complete it. Reason: Levels for Pokémon with question marks
In all six areas, the Pokémon able to be caught are exactly the same.
A colored background means that the Pokémon can be found in this location in the specified game. A white background with a colored letter means that the Pokémon cannot be found here.
A colored background means that the Pokémon can be found in this location in the specified game. A white background with a colored letter means that the Pokémon cannot be found here.
In the anime
As a boy, James was exploring the Great Marsh, and found a Carnivine stuck in the mud, struggling to get free. James pulled it out, and they became friends. Carnivine was James's friend ever since, and, during Team Rocket's journey through Sinnoh, traveled with James.
In A Skuffle with Skorupi, Diamond, Pearl and Platinum come here after Crasher Wake's assistant recommends Platinum to get a Grass-type Pokémon before challenging the Gym Leader. Here Platinum tries to catch various Pokémon, like Skorupi with no success. At some point, they get trapped in the mud. Meanwhile, wild Carnivine attacks Chatler and Lax, who fight it and win. Diamond and Pearl notice that Platinum has sank in to the mud. Chimler saves her, after which they leave, empty handed.
Trivia
A man in the Great Marsh incorrectly states that both the Bait and the Mud make Pokémon more likely to run but easier to catch.
In Platinum, if the player encounters a Pokémon when they would normally would "pop" out of deep mud, a glitch exists where upon exiting the battle, it will seem that the player is still "stuck", despite being able to move around normally. The effects of this glitch are most obvious when the player attempts to move to a tile with dry land after performing the glitch.
