EAST BAY, New Zealand
I have researched this question and have only found a reference to Arapawa Island. This is off Marlborough Sound and the Queen Charlotte Strait on the ferry approach into Picton, the ferry terminal on the South Island. East Bay is apparently on teh east side of Arapawa Island.
However, I am suspicious of this and believe that there may be another East Bay on the North Island. I have sent a request to my family new Zealand expert, my sister, a resident of Auckland. We should have an answer in 24 hours.