are you serious ? There are very substancial regulations and controls on the recreational fishing sector. Plus you are not taking into account the large numbers of fish that are released unharmed due to size limits, bag limits, or excess to personal needs.
I guess maybe you mean the total size of the rec catch, which is unlimited. In that case, let's roll out some facts and reasoning. The total value of the recreational fishing industry to the Australian economy is valued at somewhere between 10 and 100 times the value of the professional industry (no I don't have the figures on me). The pros catch more than the recs, but that is OK because all Australians have a right to eat seafood, right? Well hang on, over 70% of all Australian caught seafood is exported, and 90% of the seafood eaten by Australians is imported......so how can you justify an industry which takes a far greater share of the catch than the recs for a far smaller total dollar value to the Australian economy, has envoronmental and sustainability issues, and exists predominantly for the export dollar (ie to support itself)? The answer is, you can't.
The Qld DPI&F has published some interesting data on the catch rates by recs and pros on a number of different species. Can't find it right now, but it made interesting reading and seemed a reasonable estimate to me. But what the commercial quotas and catch reports don't take into account is the huge amount of bycatch of juveniles of many different species which is dumped back into the ocean dead. There was a big uproar about this last year in SEQ when alot of bycatch washed onto the beach. The pros dumped it on the wrong tide, wind, too close to shore or something. The rest of the time it is out of sight out of mind to most people.
Jeremy