2009 was a bad year on 2 counts. Firstly the run of fish was much poorer than normal (I think the rod catch for the year was well under 1000, which is unusual for the river) due, apparently, to floods washing out the redds a few years earlier therefore less returning fish. Then came the massive floods, probably washing out a lot of redds of the few fish that were about. Therefore one would expect a poor run some time soon.
That was only 3 years ago though and as far as I know the average cycle of 'egg-fry-parr-smolt-sea-return' takes 4 years, so if anything one would expect next year to be the really bad one?
Remember it's still a bit early for the Derwent which is a back end river. People are probably getting impatient because given the amount of rain this year they've been expecting the run earlier, which just hasn't happened. First good flood in August is still the first time many people even bother wetting a line. Besides, with all the extra water coming through, the few early fish there were were probably running hard with their heads down, so not that likely to be seen.