Answer:
Screeching seagulls.
Explanation:
A marina is a kind of a dock where yachts and smaller boats are moored or 'kept'. It is similar to a port except that it does not handle any large ships or boats.
Considering it is the docking place for ships, it is obvious that it will be near the waters. And in the waters, there are lots of seagulls flying around.
So, the sound of seagulls screeching will be heard in a marina.
