How does Zaroff stock his island with the "game?"

There are two ways that General Zaroff gets people on to
his island so that he can hunt them down and kill
them.

First, the island is in a particularly dangerous
place in the ocean.  It is very easy for ships to wreck near the island just because
that's the way the ocean is.

Second, though, Zaroff does
not just rely on chance.  He has a light set up to lure ships to go the wrong way.  That
way, he can make sure that some ships wreck if he is running low on people to
hunt.

Here is the relevant
passage:

This
island is called Ship Trap," he answered. "Sometimes an angry god of the high seas sends
them to me. Sometimes, when Providence is not so kind, I help Providence a bit. Come to
the window with me."

Rainsford went to the window and
looked out toward the sea.

"Watch! Out there!" exclaimed
the general, pointing into the night. Rainsford's eyes saw only blackness, and then, as
the general pressed a button, far out to sea Rainsford saw the flash of
lights.

The general chuckled. "They indicate a channel," he
said, "where there's none; giant rocks with razor edges crouch like a sea monster with
wide-open jaws. They can crush a ship as easily as I crush this
nut."