If those are yeast clumps there is no reason why you cannot clean/sanitize your hands and break the clumps apart, or a thorough mixing. I was taught to break apart yeast clumps.
On a side note, I have witnessed starters made from apple juice/cider develop like this and many times it is pectin related. Is that an apple juice based starter by chance?
I kept waiting for the theme music from Jaws to start playing.
Motto: quel che sara sara