In Reply to: Sew... what do you think? posted by seahunt on February 25, 2021 at 16:20:56:

In some areas where there is no wave action such as under the T-Piers in Morro Bay, bottles are home to many creatures. In open ocean reefs, sand tends to fill the bottles, blocking any chance at a home. I've found a few on rocky reefs, but I've also found broken bottles that create a hazard for any animals swimming or crawling by.

So, I think reefs would be better off with no bottles. I have a collection of old Coke bottles I've found locally. There were no animals living in any of them.