With the savage shark, another possible spawn point for it is back in the alcove underneath the waterfall to the west. Also, for money farming, my preferred method was heading to ikana castle and killing the redeads there. Equipping a garo's/captains/gibdo mask makes then dance and they won't attack, and then all you have to do is wave light from the mirror shield over them to 1HKO them. They spawn 4 at a time and each one drops either 15 or 20 rupees, and they respawn as soon as you go in and out through any door.
But does the Shark spawn there? I've seen it swim over there after spawning in the middle, but I've never seen it start over there during the dozens of times I kept running in to check the fish.
I thought about the ReDead thing, but it seems faster to do bubbles. When you fly to Ikana Canyon at night, there'll be two Bubbles right there. and the plants you can cut near the Owl Statue, along the riverbed, have arrows and magic in them. So you can Light Arrow the first, get it's purple rupee, then run to the other bubble, do the same, and the first will respawn in seconds.