Tosin007 on the Canada section keeps close tabs on populations for Canadian CMAs, using official StatsCan figures, updating them on monthly basis using known growth rates for each municipality. I think they are pretty accurate.
Using his calculations, as of July 1st, Moncton has probably achieved a milestone. The Moncton CMA has likely surpassed 150k (150,345)
Here are his estimates for the 10 largest CMA/CA populations in Atlantic Canada as of July 1st, 2016.
1) Halifax NS - 422,300
2) St. John's NL - 216,962
3) Moncton NB - 150,345
4) Saint John NB - 127,128
5) Fredericton NB - 116,140
6) Sydney (CBRM) NS - 105,649
7) Charlottetown PE - 74,575
8) Truro NS - 47,694
9) New Glasgow NS - 38,504
10) Bathurst NB - 33,220
A grand total of 1,332,517 people live in these ten CMAs/CAs, out of a total regional population of 2,381,362 (56.0%)