How does zaroff stock his island with game

Well, I'd assume that since it's Ship Wreck island, that he hunts the people that crash.

General Zaroff stocks his island with "game" by wrecking the ships that pass by the island and offering temporary sanctuary to survivors, who will eventually become the general's quarry. The general is able to wreck the ships by setting up false beacons that are supposed to indicate channels, but instead lead the ships into giant rocks, with razor sharp edges, that destroy them. Taking inspiration from big game hunting, which was a popular activity for wealthy Americans during the 1920s, "The Most Dangerous Game" was written by Richard Connell and first published in 1924.