Regarding age, I remember reading that bream and snapper are known to be very slow growing species, and one article I read from a scientific type suggested bream of 40 cm might be between 10 and 15 years old. The only real way of knowing a fishes age is by examining the microscopic growth rings on its otiliths (ear bones).
On a side note, I asked a marine biologist a while back how old an 85 cm flattie I caught would be, and after all his waffle about the accurate ways to measure age, etc etc, he estimated it might be around 15 years old.