Mobs such as Drowned not spawning.

I am searching for any type of mob for example spiders and I am having to travel hundreds of blocks away from where I started the night just to find some and even this causes little mobs to spawn, I am currently searching for a trident by killing drowned however the only drowned that are spawning are in the ruins. I do not know if mob spawning was turned down or this is a glitch.

Thanks -Yellow