Talk provided during the Scottish Fisheries Co-ordination Centre Annual Biologist's Meeting, February 3rd and 4th 2016, Milton Birnam Hotel

1. Spate impacts on Spey juvenile fish stocks
SFCC 2016

2. Do spates have an impact?
• At a population level – no
• At a fishery level - on the Spey - yes
• Hypothesis “the greatest impact of a
damaging spate will be on the smolt
output in the following spring”
• Looked at catch from smolt year
class one year after potentially
damaging spate (>500m3/s)
• Mean rod catch derived from spate
affected smolt years classes was
8,565 compared to 10,142 (p=0.007,
t-test) (MSS catch data 1952 to 2010)
Year with spate
Rod catch from smolt year
+1 Year without spate Rod catch from smolt year +1
1956 8676 1952 11511
1957 9064 1953 9798
1966 6271 1954 9108
1970 11135 1955 12545
1978 9435 1958 8498
1981 8238 1959 8534
1990 9587 1960 11656
1993 8610 1961 8770
1995 6688 1962 11540
1997 7330 1963 9627
2000 7195 1964 9406
2002 8908 1965 9556
2004 10229 1967 8463
2005 12393 1968 7634
2009 7452 1967 11611
2010 5824 1971 9400
1972 14416
1973 6901
1974 12820
1975 15126
1976 12415
1977 14304
1979 8838
1980 10652
1982 11323
1983 14252
1984 10726
1985 10436
1986 9789
1987 9526
1988 6173
1989 6876
1991 12039
1992 12977
1994 9483
1996 8730
1998 8106
1999 6619
2001 8731
2003 10073
2006 9817
2007 6314
2008 11008
Mean 8565 10142

3. General points
• Between 1961 to 2011 there were
significant increases in winter and
autumn precipitation in east
Scotland ~ 25%
• 2015 Spey mean daily flow was 15%
higher than ten year average
• The frequency and intensity of
high rainfall events has increased
• Trend predicted to be maintained
• Catchment resilience to high
rainfall events compromised
• River flow data provided by SEPA
y = 0.1524x + 60.341
0
20
40
60
80
100
120
1955
1958
1961
1964
1967
1970
1973
1976
1979
1982
1985
1988
1991
1994
1997
2000
2003
2006
2009
2012
2015
Spey autumn mean daily flow

4. Potential causes of spate related mortality
Juveniles:
• Displacement
• Stranding
• Physical damage
• Premature marine entry
• Poor post spate growth
• Predation
Eggs
• Redd washout
River bed mobility likely to be significant
factor at all lifestages
Not a new phenomena on the Spey –
noted by Ashley Cooper in book
published in 1978

5. Spate monitoring strategy
• Established network of timed electrofishing survey sites along
length of Spey mainstem – surveyed annually
• Similar surveys completed in the River Fiddich in July 2014
• Before spate data available – After spate data obtained by
resurveying some sites in Aug/Sept

6. Timed survey sites
• 61 sites on the Spey covering entire
mainstem from tidal limit to source
• Average 18.8 salmon fry/min in 2014
• Salmon fry at all sites below Spey Dam:
none above
• Parr also captured

7. River Spey mainstem before and after
spate electrofishing 2014
0.0
20.0
40.0
60.0
80.0
100.0
120.0
140.0
160.0
%offryfoundafterrevisit
River Spey mainstem % of fry Post Spate
July total
count
Sept total
count
Salmon fry 1013 604
Salmon parr 73 129 0
100
200
300
400
500
600
700
%parrfoundafterrevisit
River Spey mainstem % parr post spate
Site code Location
July salmon
fy/min
Sept salmon
fry/min
S007R1 Essil Pool 16.3 10.0
S017L2 Brae 5 24.7 6.0
S019L2 Brae 4 28.7 27.0
S025L1 Brae 2 23.0 22.0
S034R1 Delfur B o'B 55.0 9.3
S040L2 Delfur 66.0 20
S056L1 E.Elchies 43.7 29.7
S079R1 C&L 31.3 36.6
S087L1 Phones 6.0 7.3
S105L2 Tulchan D 33.7 20.3
S141L1 Castle Grant 1 9.3 13.3
Mean 30.7 18.3
Mean river flow 24m3/s 32.8m3/s

8. River Fiddich mainstem pre and post
spate electrofishing 2014
0.0
20.0
40.0
60.0
80.0
100.0
120.0
140.0
TSF01 TSF13 TSF19 TSF38
%fryfoundpostspate
River Fiddich % fry post spate
0.0
50.0
100.0
150.0
200.0
250.0
300.0
TSF01 TSF13 TSF19 TSF38
%parrfoundpostspate
River Fiddich % parr post Spate
July total
count
Sept total
count
Salmon fry 873 295
Salmon parr 112 77
Site code Location
Before salmon
fry/min
After salmon
fry/min
TSF01 Fiddichside Inn 107.3 33.7
TSF13 Balvenie warehouses 25.0 29
TSF19 Dullan confluence 129.7 22.3
TSF38 Bridgehaugh 29.0 13.3
Mean 72.8 24.6

9. Evidence of displacement/movement?
30.0
35.0
40.0
45.0
50.0
55.0
60.0
65.0
70.0
Length(mm)
River Fiddich Mean Fry length
Below Distilleries
(subject to thermal uplift)
• "Rome was built on seven hills,
Dufftown stands on seven stills"
• Fry downstream of Dufftown 25%
larger on average due to cooling
water discharges
• TSF13 only site where mean size of
fry had decreased.
30.0
40.0
50.0
60.0
70.0
80.0
90.0
TSF01
mm
Fiddich TSF01 before/after mean salmon
fry length with range
Before
After
30.0
40.0
50.0
60.0
70.0
80.0
90.0
TSF13
mm
Fiddich TSF13 before/after mean salmon
fry length showing range
Before
After

10. What did we expect to find in 2015?
• Good fry densities: there were an abundance of good quality spawning
gravels, although salmon spawning stock was low
• Reduced parr densities
• Reduced smolt output

11. What did we find in 2015?*
• Good fry densities √
0.00
5.00
10.00
15.00
20.00
25.00
30.00
35.00
FWF1 FWF2 FWF3 FWF4 FWF5 FWF6 FWF8 FWF9
Fiddich salmon fry/min
2014
2015
0.00
5.00
10.00
15.00
20.00
25.00
FWF1 FWF2 FWF3 FWF4 FWF5 FWF6 FWF8 FWF9
Fiddich trout fry/min
2014
2015
* Some observations, didn’t set out to prove anything

12. What did we find in 2015?
• Reduced parr densities √
Salmon parr/minute
River
Spey
2012 2013 2014 2015
1.2 4.3 3.8 1.5
0.00
2.00
4.00
6.00
8.00
10.00
12.00
14.00
FWF1 FWF2 FWF3 FWF4 FWF5 FWF6 FWF8 FWF9
Fiddich salmon parr/min
2014
2015
0.00
2.00
4.00
6.00
8.00
10.00
12.00
FWF1 FWF2 FWF3 FWF4 FWF5 FWF6 FWF8 FWF9
Fiddich trout parr/min
2014
2015
• Highest site count 2015
= 6 parr/minute
• Highest site count 2013
= 35.7/min

13. • 2013
• Number salmon parr = 70
• Parr > 90mm = 5.7% (4)
• 2012
• Number salmon parr = 24
• Parr > 90mm = 9.1% (2)
• 2015
• Number salmon parr = 27
• Parr > 90mm = 33% (9)
But parr were larger:
River Dulnain: Site D22
River Fiddich : Sites F4/F7
• 2014
• # Parr < 90mm = 165
• # Parr > 90mm = 38
• Total = 203
• 2015
• # Parr < 90mm = 25
• # Parr > 90mm = 30
• Total = 55

14. What did we find in 2015?
• Reduced smolt output ? River Avon & Fiddich smolt traps 2014/15
2015 Salmon Trout
Number Mean size
mm
Number Mean size
mm
Parr 19 61.9 107 102.5
Pre-smolt 564 101.5 227 133.4
Smolt 4,798 115.0 423 153.1
2014 Salmon Trout
Number Mean size
mm
Number Mean size
mm
Parr 347 63.9 217 88.1
Pre-smolt 673 101.2 218 139.1
Smolt 13,161 115.2 306 159.3
• Salmon smolt run estimate 2014
• 107,790+/-12,815
• Salmon smolt run estimate 2015
• 58,097+/-10,740
By way of contrast River Fiddich overall smolt
production almost identical in 2014 and 2015
although trap much higher up the system. 2015
salmon smolts noticeably smaller (114.8mm c/w
128mm) and younger R.A. 3.04 c/w 3.23

15. Summary
• Ex Hurricane Bertha provided an opportunity to assess impact of large
spate
• Salmon fry numbers significantly lower at monitored sites
• Greater impact at sites where the river bed mobilised
• Salmon parr numbers increased but not significantly overall
• Evidence of displacement /migration of fry and probably parr
• Monitoring suggests smolt production affected, although likely to be site
specific
• Parr densities lower in spate year +1 but numbers of large parr not affected
to same extent
• Evidence of enhanced fry growth, possibly due to reduced competition–
fewer despotic parr!
• In the Spey spates have an impact on fish densities but the plasticity
inherent within juvenile salmon population allows production gap to be
ameliorated by spate year +1