When it comes to sex, snappers are the opposite of shrimp. They all start out as females. After a year or two, some of them perform a sex-change operation on themselves and become male. Because these fish take so long to mature, populations of sea bream and snapper grow slowly. A population of mackerel that is left alone can double in size in just three or four years. For sea bream, it can take fourteen years. Furthermore, the fish are predictable. Every year big groups of them return to the same spots to spawn.
