In addition to earning Experience when catching Wild Pokemon, you will also earn Item Rewards for each Pokemon Capture. Catch Item Rewards are mainly presented in the form of Berries; however, Rare Candy and Pokemon Candy can also be received as them. These rewards vary on a number of factors, including how well you caught a Pokemon, how many Pokemon you have caught overall, and how high a Catch Combo you presently have. Pinap Berries and all its given types can be used to increase the Items you yield for capturing Pokemon.
Standard Pokemon Candy will start to be received as Catch Item Rewards after you have caught 30 Pokemon. In that same sense, L Pokemon Candy and XL Pokemon Candy can be received as Catch Item Rewards after you have caught 60 Pokemon and 90 Pokemon, respectively. As for Species Pokemon Candy, you can start receiving that as a reward after having caught 120 Pokemon. Furthermore, the higher the level of a Wild Pokemon you catch, the more likely it is for you to receive Pokemon Candy apart of your Catch Item Rewards.