You need to check the years close. After the American Revolutionary War many loyalist moved to New Brunswick. In fact, my husband's family has many roots in MASS. From Boston, there were many ships that would go north along the coast looking for supplies. People were transplanted in Maine (which was part of MASS)to log and fish. These raw materials would be returned to Boston for the "king".
So you need to look at the years and look into local historical society to see if they have any information. There was a small a muesuem on Grand Manan with all kinds of shipping history and other items that have been documented.
I also believe if my mind is remembering correctly. At one time Grand Manan there was a border dispute and some people thought it should have belong to the USA. Grand Manan is beautiful and you can still see whales from some locations on the island.
In St. John, NB, there is an excellent martime musuem which really gave you a feel of that area and the people that lived near the sea.
You might want to check if any of your ancestors fought in the war and which side they were on. You might be surprised. We have an ancestors on both sides. :)
Hope this give you something to think about and some ideas...Revolutionary War Transplants, Seeking fortune, Whaling, or perhaps they had a relationship with a local family and with a death they moved back home.
It amazed me in the 1850's in Maine for our family, that a spouse died and within a short time they were remained. Sometimes they had his and her children...and then theirs. I think a family need both a wife and a husband especially if there were any type of trade like fishing or shipping where the husband would be gone for awhile.