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.
2 Comments
Hang on. But I thought there wasn’t any evidence for fisheries induced evolution (Kuparinen, pers. comm.. Frequently).
Well, that is true in the sense that the data from wild does not stand a closer look – the evidence for genetic basis of those changes is lacking. Lab and experimental studies show that selective fishing can cause evolution. But it is another ball game in controlled situations: all kinds environmental and genetic complexities can play in the wild. But fair enough: also this study actually verifies only the fact that one can select for angling vulnerability in experimental situation. What happens in the wild might another thing. Note that I used expressions ‘should’ and ‘expected’.