Review of a Talk on the Ayrshire Rivers
by Peter Minting
The Ayrshire Rivers trust was started in 2002 with the purpose of
monitoring river quality, undertaking fish surveys, providing
education on matters relating to river conservation as well as a
range of other tasks.
Rivers trust supports the work of the Scottish Environment
Protection Agency (SEPA) with regard to the quality of the rivers in
Ayrshire. By sampling and monitoring the level of invertebrates
living in the river a clear indication can be gained as to river
pollution. The stone fly requires very clean fast running water so
if found in good numbers it indicate low levels of pollution and a
river in good order.
Pollution can occur from many sources. For example, farm
output in the form of slurry (animal waste) or nutrients both cause
damage to the water by creating high nitrogen levels which encourage
the growth of algae and bacteria and harm the fish population.
Pesticides used without care can pollute long stretches of river.
Sewage outflow after a storm will also damage a river. Sewage
treatment plants are designed to treat a maximum volume of effluent
so heavy rainfall that causes the volume of sewage to exceed the
design limit will inevitably result in excess untreated sewage
bypassing the treatment works and running directly into the river.
Surprisingly, litter on its own, whilst unsightly, does not
necessarily cause pollution. In fact eels are particularly
keen on nesting in shopping trolleys!
It is relatively rare nowadays for a factory to pollute a river.
A factory wishing to discharge waste into a river or into the sea
must seek consent and this should prevent the water from attaining
toxic levels. However, industrial activity can cause
environmental impact on rivers in many ways. For example, coal
mining can cause pollution indirectly by reducing the natural water
flow from small tributaries resulting in the main river having
reduced flow. Road building, such as the construction of the
M77, can also restrict the natural flow water in the surrounding
countryside. Also rain water running off the newly laid
asphalt will carry quite toxic chemicals that must be carefully
filtered and monitored before being allowed to flow into the local
river system. Wind farms can cause problems during the
construction phase with the use of concrete and additional road
Results of rivers monitoring in 2005:
More biodiversity has been recorded during the last year which would
suggest a slight improvement in river quality. Some local
pollution has been recorded. The river Ayr has shown good
water quality in the upper reaches but this reduces to C-class (not
suitable for salmon - not meeting EU standards). On average
the river Ayr is mainly B-class. Coalmine pollution occurred in the
River Girvan when a mine overflowed. The river went red with
rust and many fish were killed. A reed bed filter has been
introduced to reduce such pollution in the future.
Fishing and angling are a major interest regarding water quality.
The District Salmon Fishery Boards (DSFBs) and SEPA look at all
species of fish and perform regular surveys to monitor fish numbers.
One method used is called electro fishing in which an electric
current is passed into the water which attracts the fish toward you
allowing them to be netted. This is particularly useful for
counting juvenile salmon (salmonids). When fish are netted,
the rings on their scales are like tree rings in that they show the
growth in each season. At about two to three years old the
salmon becomes a smolt and heads for the sea. One matter for
concern is that the salmon are returning from the sea earlier than
normal resulting in smaller, weaker adult fish. This may
indicate a problem with seawater.
Unfortunately, it is difficult to equate the records of salmon in
the rivers today with past records. Early records included
netting salmon, a practice that is only undertaken nowadays on the
Solway Firth. As a result, there is really no long-term data
on which to base salmon numbers. Rod caught data also has
difficulties as there are often catch limits per rod which distorts
the results and local Angling societies import fish to increase fish
stocks. Peter then gave us a detailed description of the
distribution of fish in our Ayrshire rivers.
Naturally occurring species:
Wild Atlantic salmon migrate to the waters around Iceland and
Greenland whereas trout stay within a few miles of the River
entrance. Escaped farmed salmon are distinguishable by their
fat body and damage to fins due to lack of exercise and very close
proximity to other fish.
Brown trout can turn into sea trout, but not all do. Females
are twice as likely to become sea trout, perhaps due to there being
better food sources in the sea that are needed by the females to
create their eggs. Sea trout returning to our local rivers has now
become quite rare.
Arctic Char are exclusive to Loch Doon, which is why Loch Doon is
now a site of special scientific interest (SSSI). A major
problem experienced with Loch Doon is that it is based on granite
which has no PH buffering capacity for acid rain. As a result
the PH of this loch is currently 4.5 or less and salmon need 5.5 or
more to successfully breed and trout 4.5 or more. The breeding
requirements of the Arctic char are unknown but the population
levels are steadily dropping. The acidity of the water is
likely to be a major factor and efforts are being made to try and
correct the problem. One method being used is to line the
forest paths with crushed scallop shells which dissolve in the rain
feeding alkaline water into the rivers flowing into the loch.
Of course, this would require tens of thousands of tonnes of scallop
shells to achieve the desired effect. In addition alongside
the paths are habitats of exotic orchids that require acid soil!
Lampreys are migratory, so are easily blocked by river dams, etc.,
and these fish are recognised as a threatened species.
(introduced on purpose or by accident)
Grayling were introduced by accident and are are quite well
distributed on the river Ayr.
Rainbow trout were introduced by accident.
Pike and Perch introduced on purpose and occur in slow and still
waters such as lochs.
Stoneloach, Gudgeon and Minnows were introduced on purpose for live
Grey Mullet, Flounders (flowing up to 3 km inland) and Sparling.
Other work of the Trust:
Future studies and research discussed by Peter include the analysis
of fish genetics in which DNA taken from locally caught fish is
compared with data on a World database. The fish tagging is a
very expensive form of research but can reveal important information
on the movements of fish in our rivers and the Trust is hoping to
use this technique to survey Ayrshire rivers. Fish are netted
and fitted with an electronic tag that can be monitored by devices
in the riverbank giving detailed information on the day-to-day
movements of individual fish and helping to identify specific
problems with the river.
The activities of the Ayrshire Rivers Trust include a range of
projects on river restoration. The monitoring of fish movements over
obstacles such as weirs allows the Trust to identify obstructions
that are preventing easy access by fish to other sections of the
river. Designing and undertaking bankside reconstruction where
problems have been identified such as insufficient banksides
(leaving fish unprotected), landslips where the bankside has
collapsed into the river and over shading (where, for example, the
river edge is too close to a conifer planting) cutting out light and
life from that section of river. Fish do not like sections of
river that are artificially straight and lack places to hide and
rest from the river current such as behind boulders and
irregularities in the bank.
An important part of the trust's work is in the area of education
and involves presentations at schools, clubs and societies (such as
our own). A very successful activity has been "salmon in the
classroom" in which Ayrshire schools have taken responsibility for
hatching about 100 salmon eggs (supplied by local hatcheries) and
released them into their local river.
Membership of the Ayrshire Rivers
Peter pointed out that they are always grateful for new members of
the trust: with the cost of £10 for adult membership and £5 for
Junior members. Members receive regular information about news
and events and can get involved in the voluntary activities
associated with the Ayrshire Rivers Trust. Their website can be
found at www.ayrshireriverstrust.org or you can contact them by
phone on 01292 525142.
Many thanks to Peter for introducing us to the important work being
undertaken by the Ayrshire Rivers Trust. We wish them every success
for their future activities.