Complex sentence: Its only exposure to the open ocean is at the northern end, and except for this ocean opening, the TOTO is surrounded by numerous islands, reefs, and shoals which make a peripheral shelter isolating it from ocean disturbances, particularly high ambient noise.
Split into simpler sentences: Its only exposure to the open ocean is at the northern end. Except for the northern ocean opening, the TOTO is surrounded by numerous islands, reefs, and shoals which make a peripheral shelter isolating it from ocean disturbances, particularly high ambient noise.