Here's a look at some trawl survey vs. commercial catch-per-unit-of-effort statistics from 1964-1994, courtesy of NMFS.  NMFS used to compute commercial CPUE and use it in assessments. However, this was discontinued after 1995 because of the effects of the closed areas and DAS control on the catch rates (for instance, in some cases the best fishing areas were closed off). NMFS was concerned about interpreting a drop in CPUE due to a spatial change in fishing as a stock decline (or vice versa). Another reason was the shift from the voluntary interviews to the logbooks after 1994. This could potentially skew the information, and NMFS is uncomfortable with the fact that just one position (area) is reported on the vast majority of trip vessels, although they are just as likely fishing in multiple areas.

The figure below is interesting. It gives USA and total international groundfish catch off the USA between 1964 and 1994 - after which, trawl survey catches have been steadily increasing (not shown here). As well, the survey indices and USA commercial CPUE are plotted. The interesting pattern is that the trend lines between commercial catch rates and surveys are roughly parallel.