RIVER DEVERON - 1991 ELECTROFISHING SURVEY Faskally Pit

Not to be quoted without permission of the authors
Fisheries Research Services Report No 13/93
-
RIVER DEVERON
1991 ELECTROFISHING SURVEY
Ruth Matthews and Callum Sinclair
Deveron District Salmon Fishery Board
Huntly
June 1993
The Scottish Offke Agriculture and Fisheries Department
Freshwater Fisheries Laboratory
Faskally
Pit]ochry
Perthshire
.
-
RIVER DEVERON 1991 ELECTROFISHlNG SURVEY
Ruth Matthews and Callum Sinclair
lleveron District Salmon Fishery Board
Huntly
AIM
To obtain preliminary information on the distributions and abundance of
juvenile salmon and trout in the Deveron system.
METHOD
The survey was carried out in 1991 over the period July to early September
and was based primarily on sites which had been used in a preliminary
desk study (already described in a previous report).
The assessments of the fish populations were carried out by
electrofishing. The equipment used consisted of a portable 650 Watt
generator (Honda, Model EM650)coupled to a control box (Electrocatch,
Model WFCG-5H17),to supply smoothed direct current at a working voltage
of 200 t o 250 volts DC.
At each site the limits of a sampling area of approximately 100 m2
were marked with strings which were stretched across the stream. In
small streams, a representative variety of habitats was usually included.
In wider stream.5, however, the inclusion of habitat types had to be
restricted to relatively shallow areas.
The area was fished three times by a team of three. At the end of
each fishing the E.sh caught were lightly anaesthetised in a dilute solution
of MS222,identified to species and their fork lengths measured. Scales
were taken from a sample of the salmon and trout for age determination.
At the end of the fishings the fish were returned to the sample area. The
data obtained allowed estimates of the total densities of the various age
classes of salmon and trout to be made by the "Zippin"method.
Detailed habitat information was collected at each site. This
included physical characteristics such as width, depth, proportions of each
substrate type (silt; sand; gravel = maximum diameter less than 2 cm;
pebble = 2 to 6 cm; cobble = 6 to 20 cm; boulder = 20 to 50 cm: rock = over
50 cm; and bedsxk), bed character, openness and whethef silted, and
approximate surface current speed. Surrounding land use, and the
presence of cover for fish, in the form of overhanging banks or trees, was
noted. Any known obstructions likely to affect sample sites by restricting
access to spawning fish were examined and efforts were made to learn of
and locate any others which might be present. Water samples were
collected for analysis for pH, alkalinity and conductivity, In addition,
information on altitude and stream gradient was extracted from maps and
all sites were photographed.
RESULTS
A total of 71 sites was visited: 56 were desk study sites, or substitutes for
these on the samt! streams, and 15 were additional sites (sites E l to E15).
The locations of the sites are shown in Figure 1.
Details of the results are given in Table 1. To present the
information the catchment is considered to consist of five regions: Lower,
Middle, Isla, Bogie and Upper, also shown in Figure 1.
A total of six species was present, these being Atlantic salmon Salmo
salar, trout Salmo trutta, eels Anguilla anguilla, brook lamprey Lampetra
planeri, minnow Phoxinus phoxinus and three-spined stickleback
Gasterosteus aculeatus.
Of these species, trout, eels, salmon and lampreys were the most
widely distributed being found at 65 (92%), 49 (69%),35(49%) and 32 (45%)
of the 71 sites, respectively. Sticklebacks were found at 10 (14%) and
minnows at six (8%)of the sites. A t five sites on very small streams of
width of less than 1 m no fish were caught (Sites 17, 18, 43, 58 and 61).
LIENSITIES OF SALMON AND TROUT
Salmon
At sites expected to be accessible
Fifty three of the sites visited were classed as accessible to adult salmon on
the basis of ge:~tledownstream gradients and lack of any known
obstructions downstream. Of these sites, 18 were on streams of width less
than 2 m and salmon were found only at three (density 0.03 to 0.08
average 0.06 m'2); 35 were on streams of width 2 m, or over, with 30
containing salmon (0.02 to 2.03, 0.61). Of the five sites where they were
absent four were small streams of width 2 to 2.5 m; only one was a larger
stream.
C0nsiderir.g now the various parts of the catchment with particular
reference to the 315 sites expected to be accessible and of width a t least 2 m:
Lower: Five of the sites were expected to be accessible and of width at least
2 m. Salmon were found a t four of these sites a t densities ranging from
0.10 to 0.67, average 0.39; they were absent a t one site (Site 13, Craigston
Burn). Most of the salmon were of age 0 (present at four sites, densities
ranging from 0.10 to 0.67, average 0.36); at only one site (Site 19, Idoch
Water) were salmon of age 1 recorded (density 0.14). The Wree sites with
the lowest densities were small streams 2 to 2.4 m in width. The average
density of the other two sites was 0.65.
Middle: Eight of the sites were expected to be accessible and of width at
least 2 m. Salmon were found a t six of these sites at densities ranging
from 0.16 to 2.03, average 0.90; they were absent at two sites on small
streams of width 2.4 m (E14, Cunning Burn;E15, Crombie Burn). Again
they were mainly of age 0 (present at six sites, densities ranging from 0.15
to 2.03, average 0.90); low numbers of salmon of age 1 were recorded a t two
sites (density 0.01).
Isla: Six of the sites were expected to be accessible and of width at least
2 m. Salmon .were found a t five of these..sites at densities ranging from
0.06 to 1.69, average 0.54; they were absent at one site on a small stream
of width 2.4 m (Site 39, Lime Burn). They were mainly of age 0 (present
at five sites, densities ranging from 0.06 to 1.69, average 0.54); low
numbers of salmon of age 1 were recorded at one site (density 0.01).
Boge: Five of the sites were expected to be accessible and of width a t least
2 m. Salmon were found a t four of these sites at densities ranging from
0.02 to 0.44, average 0.20; they were absent at one site on a medium sized
stream of width 4.11 m (Site 55, Kirkney Water). At the site where they
were absent, low numbers were found on a repeat visit to the site later in
the year (see Appcmdix I). Salmon of age 0 were found at two sites (average
density 0.34),and salmon of age 1 and age 2 a t two sites (average densities
0.04 and 0.01).
Upper: Salmon were found at all 11 of the sites expected to be accessible
and of width at hast 2 m. Densities ranged from 0.02 to 1.65 (average
0.71). Salmon of age 0 were found at nine sites (densities ranged from 0.02
to 1.65, average 0.71). Salmon of age 1 were found at all 11sites (densities
ranged from 0.01 to 0.36, average 0.08). Salmon of age 2 were found at
three sites (densi*&sranged from 0.01 to 0.05, average 0.03).
At Sites Not Expected to be Accessible
A total of 18 sites visited were classed as unlikely to be accessible to adult
salmon on the basis of steep downstream gradients or known obstructions.
Low numbers of salmon of age 0 (average density 0.04) were recorded a t
two sites (Sites 34, and E2 on the upper River Isla above the Linn at Keith).
Trout
Trout were wideiipread in the catchment, being found a t 65 sites, with
densities ranging from 0.02 to 4.54, average 1.13. They were absent from
only six sites (Sites 10, 17, 18, 32, 58 and 61), all on very small streams
(width range 0.43 to 1.04 m,average 0.72 m).
The densities of trout found varied with stream width. This was
true for both in streams expected to be accessible to spawning trout from
the main stem rivers and to sea trout (53 sites, data in Fig. 2) and in
streams considered inaccessible, ie depending on their local resident
populations to provide spawning trout (18sites, data in Fig. 3). Over the
width range where comparison was possible there was no detectable
difference between the accessible and the inaccessible streams.
Considering now the various parts of the catchment:
Lower: Ten sites contained trout (densities ranged from 0.02 to 3.11 mm2,
average 1.20 m-2);they were absent from two sites. Densities of age 0 trout
(at nine sites) ranged from 0.02 to 2.75, average 1.24); five sites contained
age 1 trout (0.01 to 0.32, 0.12); five sites contained trout of age 2, or over
(0.01 to 0.08, 0.08).
Middle: Fifteen s::tes contained trout (densities ranged from 0.03 to 3.43,
average 1.28); they were absent from one site. Densities of age 0 trout (at
14 sites) ranged from 0.03 to 3.12 average 1.25); 11 sites contained age 1
trout (0.01 to 0.48, 0.14); five sites contained trout of age 2 (0.01 to 0.10,
0.05).
Isla: All 19 sites contained trout (densities ranged from 0.03 to 2.62,
average 0.80). Densities of age 0 trout (at 17 sites) ranged from 0.03 to
2.58, average 0.76); 13 sites contained age 1 trout (0.01 to 0.50,0.15); seven
sites contained trout of age 2, or over (0.01 to 0.24, 0.05).
Bogie: Ten sites contained trout (densities ranged from 0.27 to 4.54 average
1.65); they were absent from 1 site. Densities of age 0 trout (at all 10sites)
ranged from 0.13 to 4.37, average 1.51); all 10 sites contained age 1 trout
(0.01 to 0.41,O. 12); four sites contained trout of age 2, or over (0.01 to 0.10,
0.04).
Upser: 11sites contained trout (densities ranged from 0.09 to 3.55 average
1.31); they were absent from one site. Densities of age 0 trout (at all
11sites) ranged from 0.07 to 3.23, average 1.06); all 11 sites contained
age 1 trout (0.01 ,to 0.57, 0.22); nine sites contained trout of age 2, or over
(0.01 to 0.23, 0.04).
GROWTH MTES
I t was difficult t o compare growth rates between sites as the sampling was
carried out over a period when the fish were growing quickly. I t can be
seen from the length of age 0 fish v date information in Figures 4 and 5
that the fastest growth rates were in the Lower, Middle and Isla Regions.
There, the growtk. rates were such that many of the age 0 salmon would be
expected to smolt as one year olds the following spring and this would be
consistent with the lack of salmon older than age 0 a t these sites in
summer time. Grmerally, the average length of the trout was larger than
that of salmon of the same age.
Compaction was noted a t 13 sites. The majority of these cases involved
isolated areas with loose beds being encountered upstream and
downstream.
There were 10 sites where the proportion of the bed consisting of silt
was 20%, or more. With the exception of one site (E7, River Isla) all these
sites were on streams less than 1.7 m in width, indicating a greater
susceptibility of narrow streams to siltation.
WATER CHEMISTRY
The pH ranged from 6.36 (Site 18, Burn of Kinbate) to 9.91 (Site 4, River
Deveron). The alkalinity ranged from 271 peqA (Site 58, Burn of Pourin)
t o 2909 peqfl (Site 40, Burn of Paithnick).
DISCUSSION AND CONCLUSIONS
Generally, juvenile salmon were found in the parts of the system
which were expected to be accessible to adult salmon. The lack of
juvenile salmon in very small streams of less than 2 m in width was
expected and is not a cause for concern. Streams of width 1 to 2 m
in width were frequently well used by trout.
The presence of salmon juveniles on the River Isla above the
obstructions at Keith confirmed the passage of a few adults and may
be a useful kernel population to be built on if accessibility to adult
salmon is improved.
The densities of salmon a t sites expected to be accessible and of
width at least 2 m were poor in the Bogie Region. In view of the
good habitst found there, this suggests the possibility that the weirs
on the low(2rRiver Bogie may present a partial obstruction to adult
salmon. However, the low densities need further investigation to
confirm that the results are typical.
The Upper Region had the densest populations of young salmon,
which is most interesting in view of present worries about lack of
early running salmon which are often important users of upper
catchments.
Other than in the Upper Region estimated densities of salmon of
older than age 0 were low. We would make the following comments:
In the Upper, Middle and Isla Regions this may be
largely a result of fast growth rates resulting in many
juveniles emigrating as smolts a t the end of their first year
of life.
To allow sampling, the sites on the Deveron mainstem
were shallower than typical for the river and would have
been less suitable habitat for larger, older parr.
At a number of sites affected by past ditching
activities (see Table 1)a lack of coarse material in the bed
may have affected their suitability for larger, older salmon
parr. Trout, which use bankside cover and pools to a greater
extent than young salmon, are often less affected. Where
this has occurred some local improvements by providing
cover in the form of boulders may be possible. There is also
a need to promote awareness of the need to carry out any
new ditching or other stream maintenance in a way
sympathetic to salmon requirements.
There were reports of strandings of salmon juveniles
following heavy rain in October 1990 which may have caused
losses on some streams.
Lastly, in the absence of stop-nets the possibility of
some larger fish being chased out of the sample areas during
electrofishing cannot be ruled out.
6.
The densities of salmon and trout obtained in the Deveron Survey
may be compared with densities recorded in similar streams
elsewhere in Scotland, Comparing densities at sites of width 2 to
20 n and accessible, or at least believed accessible, to adult salmon:
Trout
Trout
Age 1
Age 0
Age 1
Deveron 1991 (20 sites)
Densities (mm2)
Average
Minimum
0.51
0
0.05
0
0
1.39
0
0.16
Maximum
2.03
0.36
4.37
0.57
Scottish survey 1983-87 (179 sites) (FFL data)
Densities(m a)
Minimum
Average
Maximum
0
3.21
0.45
Age 1
0.13
0
1.04
Age 0
0.32
0
4.17
0.09
Age 1
0
0.81
These data indicate that the range in densities, and the
average densities, of age 0 salmon found in the Deveron Survey
were similar to those found in similar sites elsewhere in Scotland,
which is reassuring. The estimated densities of age 1 salmon were
lower than those which have typically been found elsewhere and
possible reasons for this have already been discussed.
Thci estimated densities of trout were higher than those
which ha1.e typically been found elsewhere. The lack of any
detectable difference between sites on the Deveron system which
were accessible to spawners from the main stems and sea trout and
those which depended solely on their own resident populations
suggested that the streams may be at, or close to, their carrying
capacity for trout.
7.
It is recommended that this survey be regarded at as preliminary
and that there is further monitoring, particularly if there are
perceived changes in adult abundance or changes to the stream
habitat.
ACKNOWLEDGEMENTS
Many thanks to the Deveron District Salmon Fishery Board
Superintendent, Zdr Jinmy Minty, and the bailiffs, Messrs Nick Smith and
Davie Weir, for their hard work and patience with us in field work
throughout the summer.
Thanks also to the staff of the Castle Hotel, Huntly, for making us
so welcome.
Finally, thanks to the Deveron District Salmon Fishery Board, in
particular Mr Andrew Tennant, and the Clerk, Mr Christie, for all their
assistance.
The Environmental Section of FFL carried out the analysis of the
water samples. IVlr Gardiner of the Salmonid Resources Section of FFL
advised on the mterpretation of the survey data and helped in the
preparation of tht? report.
TABLE I
General table of survey results
P
P
iite
Stream
Region
Grid
ref
P
I
10
11
13
I4
15
16
17
18
19
2(1
22
El
Rivar Dweron
Den Bwn
Bum of Ryland
Crnlgston Burn
C r a i g h Burn
Burn of F'irhrie
Crlthis Bum
unnamed
Burn of Kinbeta
rower
rower
awer
rower
hwer
hwer
h e r
Lower
Lawer
ldoehwater
Lower
tower
BurnofBylh
tawsr
Burn ofGamk
Lower
BumofICirhrie
Middle
2 River Devsmn
Mlddle
3 River Davemn
Middle
4 Riwr Dweron
Middle
6 River Deveron
Middle
24 Cunnlng Burn
Middle
26 Burn ofTollo
Middle
26 Burn of Forgum
Middle
27 Glendronach Bum
Middle
28 unnamed
Middle
29 unnamed
Middle
80 Burn of AuchinCul
Middls
32 unnamnd
Middle
E4 Burnof Auchinloul
Middle
E4 Burnor Awhintod
Middle
E14 Cunnlng Burn
Middle
E16 CmmMoRurn
Ida
33 River I J a
Ibh
34 River h l a
Ida
36 River l&
leln
. 37 unmrned
181s
38 unnamed
lllla
39 Lfme Burn
Ida
40 Bum of Palthnisk
Isle
4 1 Bum of Aultmorr
Irla
48 KinmlniCIe Burn
l&
44 Burn oC Cmokrmill
l&.
46 Jock'm Burn
Imla
46 Burnof Nelhcrlon
Ide
47 ClsckBurn
Iala
E2 Rlver l8la
Isla
E5 Burn of Aultmore
lda
E6 Dnvidwn Bum
Ills
E7 River I d n
Inla
E8 River I d n
lsln
El2 River h l a
Basic
48 River Bagis
Boda
49 River Bogie
Bagis
60 BumoC Corchlnnan
Bogie
61 Back Bum
Bogie
62 Nenm Bogie
64 Burn of Tillalhrowie
Bade
Bogie
66 Kirkney Water
Bogie
67 Burn of Raw.
Bogie
68 Burn ofPourin
59 Burn oC Newmerdrum Bogie
Bogie
60 Burn of Crnig
.
W697
666589
734649
773657
769679
764687
651662
737637
764491
W0559
746470
793682
70 1499
634471
686173
543431
671628
662460
698437
626429
697431
599409
609600
682632
6126 19
609624
684508
592613
Date
lpth
12 08
1.49
12 08
13 09
16 07
15 07
14 07
14 07
15 07
19 08
18 07
)S 09
18 07
35 07
39 08
13 08
16 08
D5 08
29 07
D8 08
D 1 07
24 07
08 08
l6 08
24 07
29 07
25 07
26 07
05 09
05 09
02 08
08 M
W 07
02 08
30 07
30 07
31 07
31 07
I0 U7
08 07
09 07
16 07
19 07
l6 07
15 08
16 08
27 08
27 08
30 08
1.06
1.14
L27
1.08
1.17
0.1
0.1
606603
426507
364437
503476
6396 L7
517564
482548
466560
424620
409624
394488
414432
375436
408473
468521
419456
406468
412491
41618
619381
520295
464230
632348
503363
461329
476308
613310
507289
469284
447252
- m
22 07
26 07
03 07
02 07
03 07
06 09
26 07
14 07
22 Q7
23 07
m
m
m
RP
PR
3w G
wRD
Q PD
RP
LPD
678
663
110Z
962
1203
S36
626
804
1139
1494
668
chu
PG
tPG
D88
D83
D.37
0.16
0.1
D.29
0.18
D.08
0.11
037
0.09
0.23
0.09
0.1
0.1
Tmut
elk
1.31
1.08
L08
1.96
0.4
-
W e b r chemistrv
m
1.26
rRO
wRD
0 Bw
0
G
G
BwP
Bw G
RPG
W G T:
RPG
PRD
1070
972
2120
1021
G46
606
864
BwP
BwG
666
684
899
1933
946
PRD
PR
far
fee
far
Kem
tm
re.
Yam
No
No
Yes
Yes
G
Yen
No
Yss
No
No
No
No
Yen
No
Yem
Ye.
Y~
E
3 LS
No
No
No
No
No
No
Ye*
No
No
l l25
L404
Ye8
Yem
No
0.19
0.13
0.15
0.08
0.08
0.14
0.11
0.11
0.n
0.08
0.3
0.23
0.2
D.11
D.19
0.27
0.19
0.18
BwC
Bw
lw PC
1323
703
1088
2084
187f
2m
497
No
Yea
so3
BwP
1204
Yu
PR
863
No
RPG
136!
622
1251
868
1192
1640
1604
1569
0.23
0.12
0.1
0.18
0.23
0.18
0.12
0.04
0.1
0.23
Bw P
lw G E
RD
RP
G RP
BwC
l*GI
lw R I
BwP
Iw P c
Yes
499
392
610
Yea
Ye8
No
No
Yea
No
Yerr
No
No
Yes
Yem
434
Yea
W3
764
609
271
872
640
No
No
No
Yes
Yes
No
881
-
DSM
EL
&L
PR
-
No
No
EL
E
Yea
No
No
No
No
No
No
No
No
No
No
RGP
Yes
t
LS1
E
EL
E
E
ESL
EL
0.31
Ys.
L
No
No
No
No
No
No
No
No
No
No
No
B No
No
Ye.
Yes
No
Yes
Yes
E
No
Y6m
m
acics
ram
lea
No
498
R
GP
Nhar
E
881
BwP
G
BwG
R PG
RP
-
aa
MP
D
PR
PRD
R PG
RPG
Averap length (mm)
Tmut
went
BwR
P
P
-
Phyl
-
No
Yes
No
No
No
Yea
Yam
- Yes
E
BL
E
EL
EL
E
EL
m
E
S
ES
EL
ELk
L
EL
LS1
EL
EL
E LS
L
8LS1
No
Yes
No
No
No
No
No
No
No
EL
EL
E
L
No
-
E
E
r
I
I
1
I
Stream
River Devemn
River Devemn
River Devemn
Burn of BoHorlh
Markin WaQr
Chapel Burn
Burn Treble
Black Wnler
Allt Deveron
E10 Black WaQr
Ell Gauch Burn
E12 Glen Burn
Upper
Upper
Upper
I
I
I
Phyricnl characteristics
Wabr chemislry
I
Grid
rer
smpd
No
487406
420567
88 1286
467407
888986
420371
0
0
0
BwP
BwP
RPD
GPBw
RgCw
Yam
GRP
Yer
No
No
No
No
No
363328
336286
342265
824245
2908
440
RG
866248
4.91397
2908
0409
SS4
BwRP
BwRG
BwP
%M
G
178
M
RgY
RgA
Acc = expected accessibility as defined in the desk study;
Alt = altitude (m); Grad = local stream gradient (m.kmW1);
Depth = average depth (m); Speed = approKimate surface current (m$');
Genchar = ~ e n e r a charateristics;
l
Bw = Broken water; D = Stream ditched;
G = glide; P = Pool; R = Riffle: ~ k d u s =e ~urroundindland use; A = Arable:
B = Buildings; Cw = Coniferous woodland; M = moorland; P = Pasture; Rg = Rough
grazing
P
Water Chemistry
.
pH, alk, cond refer to the water samples taken; Alk = total alkalinity peqT1; Cond =
conductivity (pScm")
Streambed Characteristics Si, Sa, G, P, C, B, R are the percentages ofthe bed covered in silt, sand, gravel, pebbles,
cobbles, boulders, rock; siltd = silted? (YesiNo); compd = compacted? (YesfNo)
Othet Species Present
No
No
No
No
BwRG
FOOTNOTES
Physical Characteristics
-
E = eel; L = brook lamprey; M = minnow, S = stickleback
-
1
Average length (mm)
Salmon
I
Figure 3
DENSITY OF TROUT BY REGION
SITES EXPECTED TO BE ACCESSIBLE
DEVERON
,
I
10
L
I
1
I
I
I
I
l
l
I
I
L
L
I
I
I
I
I
4
I
I
I
I
I
J
I
REGIONS
m
m
1 Lower
2 Middle
3 Isla
4 Bogie
5 Upper
1 ,W
-
L
0.1
-E--
0.01
-
1
S
1
I
1
t
I
I
I
1
t
l
I
I
t
I
1
1
I
l
l
10
width (m) LOG SCALE
1
I
l
t
I
I
I
I
I
Figure 5
DEVERON SYSTEM LENGTH OF AGE 0 TROUT
BY REGION
REGIONS
1 Lower
2 Middle
3 Isla
4 Bogie
5 Upper
JUL
AUG
DATE
SEPT
APPENDIX I
As a control measure on the results FFL carried out a repeat visit to six of
the sites on 24 and 25 October 1991. Although there were some differences,
the general correspondence between the two sets of observations was
satisfactory.
River Deveron 1992. Repeat visits.
Densities (m-2)
-
R Bogie
Stream
I
I
Site
Kirkney W
I
I
490
Salmon Age 0
0.21
0
Age 1
0.07
0.03
0
Age 2
0.01
0.02
0
B of Aultmore
R Isla
440
E5 New site
330
08 07
Salmon Age 0
520
-
B of CrooksmiIl
Site
Date
-
06 09
0
Stream
Trout
24 10
22 07
I
550
-
Date
Ness Bogie
I
25 10
15 08
25 10
02 08
25 10
0.06
0
0.12
0.18
1.69
0.95
Age 1
0
0
0.01
0.02
0
0.03
Age 2
0
Age 0
2.53
0.64"
0.53
0.12
0.06
0.09
Age 1
0
0
0.10
0.03
0.01
0.01
Age 2
0
0
0
0
0.01
0
0
0
0
0
0
-
* based on extrapolation from a single fishing