Where to Harvest Silk in Ark Genesis?

Finding silk in Ark Survival Evolved Genesis is easy, but weird.  Biologically in makes no sense at all but silk is found by harvesting corals in the ocean biome, and they are pretty much everywhere.   Simply swim down, or take a tame like a frog and harvest the corals by hand or use a sickle.  You can also get plant species Y seeds from these same "plants", and equally weird these corals also yield berries.  Also making no sense is getting mushroom wood and thatch from other coral types.  I guess the Ark devs care less about biology as the game evolves, but I remind myself that it is just a game!