When flooding, the water that rises above sea level will be considered freshwater and will not cause toxicity. (This also works in multiplayer games)
Creatures no longer add their spawn points back to their spawner upon death, now they only add their spawn points back to their spawner when they are destroyed and no longer exist in the game. This means that a new creature will only take an old creature's place when the old creature is being removed from the game. This should keep there from being an excessive amount of dead creatures on the ground around shorelines. (This also works in multiplayer games)