Significant numbers of cormorants and goosanders - believed to be consuming ever increasing numbers of salmon on the Tweed's world class angling beats - will be killed this year so that scientists can study the contents of their stomachs and establish how many fish the predatory birds are taking.
The exercise which is the first of its kind on the Tweed river system for more than twenty years follows another disappointing season in 2018 for anglers out to catch salmon and sea trout. The birds, regarded as pests by the angling fraternity, have caused anger and disharmony on the river.
Official figures being presented to the annual meeting of the River Tweed Commissioners (RTC) this week show the total salmon catch last year at 6,129, a further drop on the previous year (7,003 in 2017). In total 5,644 Salmon (6,577 in 2017) were caught by rod and line and 485 (426) by net. The 2018 Sea-trout catch was less than half that of the previous season at 1,158 (2,594 in 2017).
RTC's annual report contains details of the research project on cormorants and goosanders which, it is hoped, will provide evidence to support greater control measures against the predators.
The report says: "The RTC made an application for an extended licence to
control Cormorant and Goosander from 1st October 2018 through to 31st May 2019,
as Scottish Natural Heritage (SNH) had agreed last year. In addition, the RTC requested
a larger number of birds to be taken in some months to fulfil the requirements
of a study to look at the current dietary make-up of the birds, to be
undertaken by the Centre for Ecology and Hydrology (CEH) in Edinburgh.
"That
work had last been carried out in the 1990s when the main constituent of the
diet had been eel. A few samples had been collected by the RTC during 2017 and
sent for analysis, but a larger, coordinated, study was required. During
lengthy consideration of that request, the RTC was issued with several interim
month-long licences throughout the autumn period by SNH to enable the usual
control and scaring regime to take place.
"At the end of the year, a compromise
was agreed with SNH enabling a dietary analysis study to take place during 2019,
involving several rivers, and being led by Marine Scotland."
The Commission's report adds that due to the increase in Cormorant numbers on
the Tweed, the Fishery Officers actively monitored and recorded numbers -
especially at roosting sites around the catchment - to help collect data for
future licence submissions for control measures.
"With growing populations of
piscivorous [fish-eating] birds being seen on many rivers, a dedicated group has been set up
comprising representation from Marine Scotland and Marine Scotland Science,
SNH, Fisheries Management Scotland and the Fishery Boards and Trusts to debate the
whole issue and approach to predation control and to find a way forward.
"In addition to continuing to press the authorities for a
larger licence to better protect the smolt run and juvenile stocks of Salmon
and Trout, the RTC is also developing non-lethal techniques to disrupt feeding
patterns and discourage roosts."
The vexed question of cormorants and goosanders also features in the section of the report written by RTC chairman Douglas Dobie who is standing down after seven years in the post.
Mr Dobie writes: "Goosanders are prevalent throughout the catchment and the
number of semi-resident Cormorants have increased significantly in the past few
years.
"Whilst a decline in fish stocks, particularly migratory, is unlikely to
be attributable to a single cause, it is distressing for anyone closely
involved in the well-being of the river regularly to watch large numbers of
piscivorous birds hunting in flocks of up to 50 – 100. This would not have
happened 20 – 30 years ago and the numbers we see today will be having an
impact on all freshwater fish stocks."
He concedes that the
Commission’s executive and Tweed Foundation staff had come under considerable
criticism for not “doing enough”, particularly in relation to piscivorous
birds, but reminds stakeholders of the measures taken so far.
Mr Dobie comments: "I am not seeking re-election in 2019 and, although I have
really enjoyed many aspects of my involvement over the last seven years, it has
been a turbulent period.
"The dramatic decline in Salmon catches has resulted in
a loss of confidence, anxiety and anger at the present position leading to a polarisation
of views often sustained by an unconscious bias towards only listening to
like-minded opinions. Everybody involved should be working to find a consensus,
not discord, restore trust and to maintaining the Tweed’s international
reputation for management based on sound evidence and sound science."
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