Grade creep………or it is easier to get an “A” pass nowadays?

As discussed in recent posts I like to use the SFCC electrofishing classification to put our Spey survey results into some sort of Scottish context. However the worth of the SFCC classification scheme has been challenged by some primarily on the grounds that it is a relatively modern scheme (based on survey results from 1997 to 2002) and that an “A” grade result now may only have been “C” grade in earlier years, a time of greater abundance of spawners. My initial response was to say that as parr have always been territorial there is a limit to the density an area of habitat can support. However I have consulted with some of my colleagues from around the country including Dr. Jason Godfrey who produced the SFCC classification scheme. His response included saying that the classification scheme showed things as they were at the time, not how they should or could be. But he also  thought there would be little change at the top end of the scale, i.e. an “A” then would be an “A” now but that there may have been more sites at low abundance where there are no fish now. That implies that the breakpoints between each grade may have been slightly higher than the 97-02 class.  We will never know however as there is very little standardised electrofishing data available prior to that date.

One explanation for the possibility of higher number of sites supporting salmon at the lower end of the spectrum then compared to now can be likened to the situation that occurs if you board a busy train in the middle of its journey. If you board one of the middle carriages all the seats may be taken but if you go to either end of the train there are usually empty seats. Only when the train is really full will there be no seats at the far end. Salmon spawning in a burn can be a bit like that: there needs to be a lot of spawning fish to ensure that all the habitat is utilised.

And of course why should everything refer to the period of highest abundance? The 60s and 70s were considered to be a period of superabundance for atlantic salmon with marine survival and adult returns well above typical levels for the last century.  Is that the right benchmark on which to base more recent results? I have been an Aberdeen fan since 1970. In those days the odd cup final was about the best you hoped for then Fergie came along. If we gauge Aberdeen’s performances by the standards of the early 80s all Dons fans would be suicidal by now! Thankfully we had those glory days to bask in, who knows they may be about to return – sitting third in the league with a great crop of youngsters coming along, things are looking good. Compared with the last five seasons Dons fans are smiling again.

No matter what the starting point is we should always be striving for improvements. We need to be aware that the SFCC classification has its limitations but it is a robust starting point on which to base our current results. There are refinements to the SFCC national grade including regional classes (Moray Firth region being one) and correction factors for stream width. We will probably move to using the more detailed Moray Firth classes based on stream width but I’ll elaborate on that in the next post.

Glory days!

 

 

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