SFCC Biologists' Meeting - Wester Ross Update 2024.pdf

Presentation at the annual SFCC biologist's conference in 2024.

1. Wester Ross Fisheries Trust 2023 – 2024
Chairman
Prof Dave Barclay
Administrator
Peter Jarosz
Biologist
Peter Cunningham
Tournaig trap
Ben Rushbrooke
NatureScot trainee
Dr Shraveena Venkatesh
Field assistant
Nic Butler
Research scientist
Dr Steve Kett
(Trustee)
Field assistant
(Trustee)
Alasdair MacDonald
Field assistant
(& Trustee)
Mark Williams
Administrator
Dr Sue Ward
& lots of other helpers . . .

2. Catchment
vegetation
revival
workshop
Kinlochewe
26
th
April 2023
also
live-streamed
https://www.facebook.com/
WRFT22

www.wrft.org.uk

3. https://www.catchments.ie/natural-water-retention-measures-
implementing-the-flood-risk-management-plans/
Mitigation at catchment scale?

4. Review of the Field Excursion at Beinn Eighe NNR
on 25
th
April 2023

5. https://www.bing.com/maps/?cp=57.7
08549%7E-4.809265&lvl=9.0&style=a
Fertilised (in 1961) plot
25
th
April 2023

6. Catchment vegetation revival meeting, Beinn Eighe NNR and Kinlochewe, 25
th
and 26
th
April 2024
Restoration of thicker,
spongier vegetation
through restoration of
upland fertility, as
demonstrated at Beinn
Eighe NNR . . .
. . . can help to moderate
rapid run-off of rainwater
and sediment from
upland areas . . .
. . . so less flooding.

7. Sea lice monitoring 2023
Heavily lice infested sea trout in April 2023 at Gairloch
and May 2023 at Applecross
Need to find a way to be able to share sea lice data from
EMPs across Scotland to understand and analyse the
regional sea lice situation in real time

8. Boor Bay, Loch Ewe, coastal fyke net (for sea
trout)
Catch dominated by juvenile gadids (pollack, cod,
coalfish, poor cod) carrying high infestation of
Cryptocotyle lingua

9. Marine heat waves in summer 2023 for Minch
Barrell jellyfish on shore at Loch Kanaird,
6
th
June 2023
Thankyou to Sam Jones at SAMS and to Keith Dunbar for forwarding on sea
temperature graph. The satellite sea surface temperature (SST) dataset is from
NOAA, and the Loch Ewe timeseries is maintained by Marine Scotland.

10. Wester Ross
Marine
Protected Area
The Wester Ross MPA
was designated to
protect maerl and
other seabed habitats
of nature
conservation concern
https://youtu.be/kXPyCqUrm8
A

11. Filamentous algae has grown over
the maerl beds in upper Loch
Ewe.
The filamentous algae restricts
the amount of light reaching the
coralline algae that forms the
maerl, and alters the ecosystem.
Species may include Pylaiella
littoralis and Ectocarpus sp. We
need someone to help to identify
them!
Why is there filamentous algae
growing over maerl beds in Loch
Ewe?
However, some maerl beds have a blanket of filamentous algae growing over
them

12. Maerl has been recorded in many parts of Loch Torridon where there
is more open cage salmon farming than in the Wester Ross MPA
Are maerl beds in Loch Torridon
healthy?

13. Loch Torridon sea grass and maerl snorkel expeditions, summer 2023
There was filamentous algae on both seagrass and maerl in Loch Torridon

14. 17 June 2001 (photo by Sue Scott) 15 June 2023 (photos by Peter Cunningham)
Upper Loch Torridon maerl bed (same place same time of year)
There was much more filamentous algae on the maerl in June 2023 than there was in June 2001
June 2001 June 2023

15. Figure 19: Illustration of the environmental effects of finfish aquaculture (provided by Hilke Giles).
From: James et al (2018) Assessment of ecological effects of expanding salmon farming in Big Glory Bay, Stewart Island – Part 2 Assessment of effects
https://www.es.govt.nz/repository/libraries/id:26gi9ayo517q9stt81sd/hierarchy/environment/consents/notified-consents/2018/sanford-
limited/Assessment%20of%20Effects%20Volume%202%20-%20Aquatic%20Environmental%20Sciences%28Mark%20James%29.pdf
Is cumulative nutrient
enrichment associated
with open cage
salmon farms harming
‘protected’
maerl beds?
Can SEPA classify
coastal waters as
‘good ecological
status’ if protected
habitats damaged by
filamentous algae?

16. Government
Agencies are not
always
successful at
preventing
eutrophication
until much
damage has
been done . . .

17. WRFT Juvenile fish surveys 2023

19. NEPS reporting has focussed on
estimated numbers of fry and parr / m
2
Growth and biomass of fry and parr / m
2
are
important for assessing health and estimated
smolt production and smolt size
Big fat smolts have higher rates of marine survival
than small skinny ones (c. Armstrong, et al 2018)

20. Allt Beith parr
Gruinard parr
Huusko et al (2011) found that juvenile salmon may shrink when subject to harsh
living conditions, with shortening of the spine.
Gruinard River: malnourished salmon fry?
Big differences in Wester Ross between size and condition of juvenile salmon
in different rivers

21. 0
5
10
15
20
25
30
35
40
30-34 35-39 40-44 45-49 50-54 55-59 60-64 65-69 70-74 75-79 80-84 85-89 90-94 95-99
100-104 105-109 110-114 115-119 120-124 125-129 130-134 135-139 140-144 145-149 150-154 155-159 160-164 165-169 170-174 175-179 180-184 185-189
Estimated number of fish per 100m
2
Juvenile salmon length class (mm)
Estimated numbers of salmon per 100m
2
at NEPS23_03710
Dundonnell River, by new shed,
8th Septmember 2023
3 runs (strings). Site length 14.7m; width 11.76m; area 172.87m
2 0
10
20
30
40
50
60
70
30-34 35-39 40-44 45-49 50-54 55-59 60-64 65-69 70-74 75-79 80-84 85-89 90-94 95-99
100-104 105-109 110-114 115-119 120-124 125-129 130-134 135-139 140-144 145-149 150-154 155-159 160-164 165-169 170-174 175-179 180-184 185-189
Estimated biomass (g) per 100m
2
Juvenile salmon length class (mm)
Estimated biomass of salmon per 100m
2
at NEPS23_03710
Dundonnell River, by new shed
8th September 2023
3 runs (strings). Site length 14.7m; width 11.76m; area 172.87m
2 69.4
3.9
28.3
Estimated number of salmon per 100m
2
FryParr <80mmParr 80mm+ 102.36
18.78
287.88
Estimated salmon biomass (g) per 100m
2
FryParr <80mmParr 80mm+ The total minimum density of juvenile salmon at this site NEPS23_03710 in the Dundonnell River on
8
th
September 2023 was 101 juvenile salmon / 100m
2
, and total biomass 409 grams of juvenile
salmon / 100m
2
. In addition to juvenile salmon, juvenile trout and many eels were recorded at 3
small trout and 8 eels per 100m
2
(lengths 92mm – 380mm). Many other eels were seen but not
caught; the biomass of eels may have been as high or higher than that of juvenile salmon at this site.
Dundonnell River
8th September 2023
•3-run NEPS site
•estimated smolt
production of
>20 smolts per 100m
2

well nourished parr

22. The total estimated minimum density of juvenile salmon at this site
NEPS23_03717 in the Gruinard River on 7th September 2023 was 39
juvenile salmon / 100m
2
, and total estimated biomass 110 grams of juvenile
salmon / 100m
2
. In addition to juvenile salmon, two juvenile trout and two
eels were recorded.
Gruinard River
7th September 2023
•1-run NEPS site
•Estimated smolt
production of
<5 smolts per 100m
2
malnourished parr?

23. 0
20
40
60
80
100
JanuaryFebruaryMarch April May June July AugustSeptemberOctoberNovemberDecember
% of total number of organisms eaten
Food of salmon parr, River Bran and tributaries
Number of food organisms expressed as % of the total organisms eaten
from Mills (1964)
Oligochaeta Cladocera Flat-bodied mayfly nymphsOther mayfly nymphs
Stonefly nymphs Caddisfliy larvae Water beetles Chironomid midge larvae
Simulium (black flies) Other insects nymphs & larvaeSnail Winged aquatic insects
Terrestrial insects Salmon fry Trout eggs Mayfly and
stonefly larvae
Winged insects
including terrestrials
Caddisfly larvae
Fish eggs . . .
What do salmon parr eat at different times of year (if they can find it . . . )?

24. How important
are surplus
salmon eggs?
Research over past
20 years has
focussed on
instream indirect
trophic pathways via
streambed flora and
fauna.
For some rivers in
Wester Ross
surplus ‘washed
out’ eggs may have
provided many
vital meals for pre-
smolts.

26. Thank you to:
and to estates, members, other supporters,
and many volunteers for lots of in-kind help
in 2023