where did the limestone caves go

[Milurian]

I cant seem to find the limestone caves again after passing their point in the main story it just isnt in the map anymore need them to get a 3 star anglerfish and one of the seahorses.

[Nokturnal]

The limestone cave spawns randomly usually during the Afternoon dive though. (At least in my experience) Far as the Seahorses, from my experience it's pretty random where they show up but I got them all pretty easily.

[Tenjou]

Each time you go under water, the world generates itself Randomly. So, if you dive under the water and do not get the Biome, or fish that you seek, you can exit the game and reload and see if you get the one you want.

That's actually how I found the seaweed Biome for the very first time. I went under, then realized I forgot to switch sub weapons. So I F4'ed then reloaded and this time the elusive seaweed+Limestone Biome appeared together.