Sea Bounty question

[WhySoSalty]

So heres the question: there are 44 sea bounties to collect in this game right now, and 4 of them (Totoiki Boat, Sirene, Aurora and Ghost Stingray) are apparently on a Shipwreck. So i found out that Shipwrecks got removed in the last season and now you can get this 4 maps from the sea gates.
So heres the actuall question. does it have to be a specific gate like eart, wisdom or whatever or can i get all 4 maps from the lowest harmony gate?