Everyone is after the rare big ones. Why the big ones are rare is an interesting question itself, but by definition, it is this rarity which makes them attractive for recreational fishermen.
With increasing fishing pressure, there is a risk that the big ones are getting even more rare, especially if the size and likelihood of capture are genetically determined and correlated. In a long-term selection experiment, US scientists have now shown that the vulnerability to angling in largemouth bass is moderately (h2 = 0.2) heritable. This means that in a long run, fish vulnerable for angling should become rare, and the expected catches should drop.
In fact, continued directional selection by angling is expected to erode all genetic variability in angling vulnerability, and the likelihood catch should then become of function of factors of mainly environmental (e.g. hunger) origin, or perhaps, skill of the fishermen. So, the good news is that sport fishing is bound to becomes more sporty!
Phillipp DP et al. (2009) Selection for vulnerability to angling in largemouth bass. Transactions of the American Fisheries Society 138:189-199.