Also on the shoal is another fisherman.

Battle: Fisherman Vince (1280 Poke)
Opponent: Golduck Lv 40

Pass Vince to the South if you like, but the other shoal here doesn’t have anything on it.  The island is full of dark grass, at the center of which is a Luxury Ball just lying around.  The dark grass contains the same pokemon as the regular grass, but the levels are upped a bit, to a range of 38-41.

Head back to the land to the West, and follow the sand below the cliffs inland.  An Ace Trainer is here, but he’s just looking around, and will hand you a random unusual item that he’s found- the glass flutes from Ruby/Sapphire/Emerald are a common option, among other things.

There’s nothing of note or value in the house here, sadly, so head back to where the Parasol Lady was and then north.  You’ll quickly spot a fisherman-

Battle: Fisherman Damon (1248 Poke)
Opponent: Basculin (Red) Lv 39, Staryu Lv 39

-and another one too.

Battle: Fisherman Jones (1280 Poke)
Opponent: Alamomola Lv 40

Continue North on the spit of sand onto the far beach, where another Pearl is hidden in the sand, then take the stairs up to the top of the cliff.  This puts you near the end of the route, so make note of the spot (the pair of Cut-able trees is a good landmark) and head South across the footbridge.  You’ll quickly come to a grassy clifftop where an Ace Trainer waits for you.

Battle: Ace Trainer Angi (2460 Poke)
Opponent: Lopunny Lv 41, Lampent Lv 41