The thing that differentiates a comercial harvests from sports harvest is that when somebodies livelihood is depending on maximizing the harvest, they are very resistant to any sort of reduction in opportunity even when the evidence clearly supports such regulation.

Sports fishers are much more receptive to regulation for the fishes sake (it only a hobby, not their livelihood).

Commericialization of a public resource in general doesn't lead to good managment of the resource. Look at public forests, mineral deposits, and fish. Thankfully large wild animals are now spared from overt commerical harvest.

Salmo G,
I'm sure you are well aware of the political pressures brought to bear by commericial fishers on fisheries managment agencies. Many managment decisions are made based on politics, not what is best for the fish.

The simple political ineptitude of sportsfishers makes them easier on fish populations!
This is because fisheries managers can regulate sports catches more easily, without as much political interference from the sportsfishers. However, I think this is starting to change.

My $.02