In the Tay catchment we are fortunate compared to the other major Scottish salmon rivers in having a number of fish counters to assess the strength of salmon runs. The counters are nearly all located on spring salmon tributaries, mostly on hydro electric installations. The most important counter, at Pitlochry Dam, is situated on the lower reaches of one of the most productive spring salmon tributaries in the district. Furthermore, up to only a few years ago there was also a counter on the lower reaches of the River Ericht, the Tay's most productive spring salmon tributary but this was lost when the weir housing it collapsed. Thus until a few years ago probably more than half the Tay spring run was counted, providing valuable insights into the status of spring salmon.
(Data kindly supplied by SSE)
Annual “net” upstream counts at Pitlochry Dam, River Tummel, (that is down counts are subtracted from upcounts on a daily basis), 1951– 2013
Net monthly upstream counts, Pitlochry Dam, 1951 to 2013. Monthly data are not available between 1987 and 1991.
Pitlochry Dam spans the River Tummel, one of the major tributaries of the Tay. All salmon ascending must pass through a fish pass within which a fish counter is located. Also there are glass panels in the fish pass wall which allow salmon to be observed (see video clip). This facility is open to the public during the day.
The River Tummel is one of the main areas for producing spring salmon in the Tay district so this counter is particularly valuable for assessing spring salmon numbers, although there are some difficulties in interpreting the data which are explained in more detail by clicking here.
The overall total count for 2013 was one of the best counts since the late 1970s. However, the count to the end of June was the best since 1978 and that to the end of July was only slightly less than those of 1995 and 1980 and not significantly bettered since 1979.
The counts post July 2013, were not remarkable, however.
Counts through Pitlochry Dam are practically wholly composed of MSW salmon up to end May (though the MSW salmon ascending in May or indeed later need not have entered the Tay in May, but could have done so even earlier). In June, in recent decades, the count has composed of both MSW salmon and grilse, particularly later in the month. From July onwards grilse can dominate. That at least was the pattern in the late 90s / early 2000s, for example.
However, because in the last few years summer grilse have either tended to enter the Tay and other rivers later than they did previous to circa 2005 and in the last few years appear to have been less numerous, the recent June counts are also likely to be dominated by MSW salmon, while even July counts are likely to be comprised of a higher proportion of MSW salmon than prior to say 2005.
Therefore, it may be concluded that though the grilse count in 2013 may not have been a strong one, the MSW salmon count was very strong therefore. The best since the late 1970s, although the previous two years also saw a similar pattern too.
(Data kindly supplied by SSE)
Annual net upstream counts through Clunie Dam fish ladder, 1953 to 2013.
(note: counter malfunction occurred in 2005)
Net monthly upstream counts, Clunie Dam, River Tummel, 2003 to 2013. Monthly data are not available prior to 2003. Also, note malfunction in 2005.
The total count at Clunie Dam on the River Tummel (Clunie Dam is upstream of Pitlochry Dam) for 2013 was in the higher region of those historically recorded. The June count was notably better than it has been for a few years, presumably reflecting the strong MSW salmon run that passed through Pitlochry Dam in May and June. Greater than normal numbers also ascended Clunie in September and October, but that was perhaps a result of delayed migration during the hottest period of the warm summer of 2013.
(Data kindly supplied by SSE plc)
Annual net upstream counts, Lochay Falls, 1960 to 2013 (note malfunction in 2012).
Net monthly upstream counts, Lochay Falls, 2003 to 2013 (note no data prior to 2003 and malfunction in 2012).
The Lochay Falls are a naturally insurmountable barrier to salmon on the lower reaches of the River Lochay near Killin. As compensation for the loss former spawning areas on the River Lyon through damming, the North of Scotland Hydro Electric Board installed a borland fish lift to allow salmon access to the Lochay.
The 2013 count was the largest for 15 years with exceptional counts in June and July, echoing the counts at Pitlochry Dam. Perhaps this represents a Tay wide increase in spring salmon smolt / marine survival. However, it is also the case that this cohort of fish came from an increased juvenile population following increased stocking and fish passage improvements (see page 21 of http://www.tdsfb.org/documents/TayTributariesElectrofishingSurveyReport.pdf).
Annual upstream counts, River Ericht, 1990 - 2010. Grey additions represent possible additional counts in years of counter malfunction (1998, 2000 and 2001) but in 2003 is indicative of fish which were unable to ascend past the counter because of a drought late in the autumn but were rescued and transported upstream by TDSFB staff
Monthly upstream counts, River Ericht, 1993 - 2010. No data are available for 1996 nor before 1993. No spring counts are available for 1998 or 2000 when the counter malfunctioned.
The River Ericht counter was situated at Blairgowrie, only a few miles above the confluence with the River Isla. It was situated upstream of a waterfall, Cargill’s Leap, which like Pitlochry Dam, acts as a temperature barrier. Therefore the timing of spring counts especially was no reflection on when the fish might actually have entered the Tay.
The counter was installed in 1990 but following the 2010 season the weir on which it was situated developed a breach and since then fish no longer use the fish pass and the counter had to be removed.
The now historic count data are shown here for information.