In response to Nuggs original question I doubt there would be more fish, at least not in the long run. If perch were magically to vanish overnight then perhaps next season you might see an increase in a variety of fish species fry.
But go a bit further and 5 years down the road would see siver fish populations maybe larger but would include a larger proportion of breeding fish that are genetically unsound (natural fodder). But this would not happen as other predatory fish would fill the vacuum (nature abhors one) left by the perch. Pike would proliferate (more pike fry would survive too). Some other species might also take advantage of the superabundance of fry.
The predator/prey ratio would head towards whatever previous balance was sustained in the water before, but now the proportion of pike has increased. So, more of the "hated" pike (especially those 3lb jacks) will be around, more caught and seen.
I doubt whether more fish would be around for anglers os Esox lucius (maybe good for Esox lucius anglers though).