Nether fortress spawn spawn rates too high

So this is my first time I have been in the nether since the Nether update so please correct me if this is normal. The spawn rate I have noticed in the nether fortress is so high that blazes literally fill the fortress in less than a minute or two.

In fact the image I have attached can not have been more than 1 min after I changed the difficulty from peaceful to normal.

 

Please it is nice to have this fixed so I don't need to worry about getting overwhelmed by an army of blaze that just never seem to end.