The Title Update 69 - Update Aquatic Title update for Minecraft: Xbox 360 Edition has 6 achievements worth 170 gamerscore.
Eat nothing but Kelp for 3 days.
Stay underwater for one full day without using potions.
Place four Sea Pickles in one block.
Activate a Conduit.
Use a Dried Kelp block as fuel in a furnace.
Bribe a Dolphin.