It’s called the “Blood Kelp Zone” for a reason.

SPOILERS. I usually like to go to the blood kelp trench before going to the gun island/sunbeam that way I can get blood sacs and deep shrooms/whatever they are called, before the warpers get angry with me. You can get plenty from the trench relatively safely.

It should be sw from the pod there is a gaint cavern just go down it or look at a tutorial