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Fish population


The River Ythan fish population is regularly surveyed. Surveys have been run in the following years by various organisations: 


2018 onwards  - Scottish National Electro Fishing Project

2016 - Scottish Environment Protection Agency (SEPA)

2015 - River Ythan Trust and the Ythan District Salmon Fishery Board

2011 - Deveron, Bogie and Isla Rivers Charitable Trust for the River Ythan Trust

2010 - Scottish Environment Protection Agency (SEPA)

2002-08 and 2014 - Sandy Milne, former river superintendent for the Ythan District Salmon Fishery Board

1996 - Scottish Conservation Projects Trust


Highlights of the results of each survey can be found below.

Electro fishing


This is a technique that uses an electrical current to briefly stun fish allowing them to be swept into a waiting net and removed from the water for analysis. It doesn’t do lasting damage, when done properly, and fish recover completely within a few seconds. An electronic pulse is created by an electro fishing system that can be battery operated via a backpack or generator operated through a bankside system. The charge is emitted by a hand held ‘wand’ passed through the water in proximity to the fish which in their stunned state float to the surface to be collected in a net.


The survey technique involves a number of team members and a high degree of training and experience between members. In Scotland, most people follow electrofishing methods standardised by the Scottish Fisheries Coordination Centre (SFCC) and accredited training is provided by the SFCC in partnership with Inverness and Barony colleges.


The data enables us to determine the distribution and ages of different fish species, assess how healthy the fish population is by comparing numbers with what we expect, and track changes in species diversity and abundance over time. In this way we can find out where there is a problem for fish and how bad it is. This then leads us to identify issues, find solutions and make improvements for habitats and the species they support.


Survey methods range from super-fast that tell us which species are present at a site and give a broad indication of relative abundance, to in-depth that take much longer to complete, but give us an accurate estimate of fish densities. As with any form of data generation, a lot of thought is given to what the data is to be used for and check that it really is suitable for that purpose.

   

How the data is used


The data collected is used to:


  • provide long term records for comparison of trout numbers and juvenile salmon numbers over several years

  • establish the presence/absence of juvenile salmon throughout the catchment.  The lack of juvenile salmon may be due to obstacles to upstream migration, poor habitat etc. which can be investigated with a view to resolving the issues

  • to keep a record of other fish (notably lampreys) and eel species through time


Data can and has been issued to SEPA as evidence to support removal of manmade obstacles.


Scottish National Electro Fishing Project (from 2018)


The Project


A nationwide nine year electrofishing project funded by Scottish Government/Marine Scotland to try to get an idea of what fish species exist in our rivers and streams – the Ythan District Salmon Fishery Board and the River Ythan Trust are of course primarily interested in trout and juvenile salmon.


The exercise on the Ythan and tributaries has been/will be carried out by staff from the Deveron, Bogie & Isla Rivers Charitable Trust.  Surveys have been carried out in 2018 and 2019. 


In 2020 Marine Science surveys will not take place due to COVID 19 restrictions. The Ythan District Fishery Board has, however, commissioned the Deveron, Bogie and Isla Fisheries Trust to survey the 4 ‘annual sites’ (3 on the Ythan from above Methlick to downstream of Auchterless and 1 on the Fordoun burn upstream of Fyvie) (these sites will be surveyed annually for the period 2018 – 2029). The surveys will take place in late August / early September 2020.


This data will be uploaded onto the SFCC database along with all of the other records taken under this project since 2018 and shared with all interested parties including Marine Science who commissioned it. It will also be shared here.


Electrofishing Site Selection


The sites were selected randomly by Marine Scotland – a few had to be altered slightly from their original locations to enable the electrofishing to take place (water too deep or not enough water.)


The decision to take the random selection route is to ensure that neither trout nor juvenile salmon habitat took preference.


Size of Electrofishing Sites


Each electrofishing site is approximately 100 sq. metres in area. Where no salmon fry or parr were found this does not mean none are in areas adjacent to selected sites.  Salmon fry, salmon parr and trout tend to occupy differing underwater habitats, although trout are less selective – see the results - trout present at every site.


The National Fisheries Classification Scheme


We have used the information from the above scheme to interpret the results of the surveys – 0 (none found), poor, fair, good, and excellent - this will give the reader some understanding of the density of species at each site.


The 2018 Electro Fishing Survey Results


The good news is that the water quality at every site was good enough to support trout.


Note abbreviations: ms - main stem, s - salmon, t - trout, us - upstream, ds - downstream


Ythan ms Slaties Pot opposite Ardlogie – s fry numbers fair, s parr numbers fair, t fry numbers fair, t parr numbers fair.


Ythan ms Mains of Towie – s fry numbers 0, s parr numbers 0, t fry numbers good, t parr numbers good. SEPA’s e/f exercises have found juvenile salmon near this location in recent years.


Ythan ms ds Lochcam Pot Methlick – s fry numbers good, s parr numbers fair, t fry numbers good, t parr numbers fair.


Ythan Fordoun Craig-an-Gobhair Wood, Fyvie Estate – s fry numbers poor, s parr numbers good, t fry numbers excellent, t parr numbers fair. Good to see some salmon have ascended the Bridge of Lewes Weirs in Fyvie.


Ythan Ebrie mouth of ditch at Mains of Drumwindle – s fry numbers fair, s parr numbers 0, t fry numbers good, t parr numbers fair.


Ythan Ebrie Fortree Burn slightly ds South Auchnavaird Auchnagatt – s fry numbers 0, s parr numbers 0, t fry numbers excellent, t parr numbers excellent.


Ythan Little Water east of Little Gight Cottage – s fry numbers poor, s parr numbers excellent, t fry numbers poor, t parr numbers fair.


Ythan Raxton Burn slightly us of Nethermill of Tillyhilt – s fry numbers 0, s parr numbers 0, t fry numbers good, t parr numbers excellent.


Ythan ms slightly ds Brewer's Pot opposite East Mains of Ardlogie – s fry numbers excellent, s parr numbers fair, t fry numbers good, t parr numbers good.


Ythan Ebrie slightly ds Arnage South Lodge opposite Mains of Arnage – s fry numbers fair, s parr numbers fair, t fry numbers good, t parr numbers good.


Ythan Skeugh (Tifty) slightly us Monks Burn at Tifty Bridge – s fry numbers 0, s parr numbers 0, t fry numbers excellent, t parr numbers excellent – SEPA’s recent surveys have found juvenile salmon around 100 metres below this site.


Ythan Fordoun ds Rothienorman us Borestone Bridge – s fry numbers good, s parr numbers 0, t fry numbers excellent, t parr numbers excellent. Good to see some salmon have ascended the Bridge of Lewes Weirs in Fyvie.


Ythan Ebrie SE Mains of Inverebrie Cottage – s fry numbers good, s parr numbers 0, t fry numbers fair, t parr numbers good.


Ythan ms Gight 390 m above the Round Pot – s fry numbers poor, s parr numbers fair, t fry numbers poor, t parr numbers fair.


Ythan Foveran Burn near Larchcroft west of Foveran Village – s fry numbers 0, s parr numbers 0, t fry numbers fair, t parr numbers good. A finnock was found by the Don Trust just below Foveran Village when electro fishing in connection with the AWPR work.


Ythan Burn of Howemill us Bridge of Kingsford – s fry numbers 0, s parr numbers 0, t fry numbers excellent, t parr numbers fair.


Fish survey by the Scottish Environment Protection Agency (SEPA) (2016)


Ythan main stem Towie Barclay Castle – trout present moderate numbers, juvenile salmon present but in poor numbers, eels, lamprey, and stickleback also found. (Trout far more numerous than salmon).


Ythan main stem Newmill Bridge Auchterless – trout and juvenile salmon present, both in moderate numbers, lamprey  also found.


Ythan main stem 45 metres downstream of Tanglandford Bridge – trout and juvenile salmon numbers both good, eels also found.


Ythan main stem Ellon just below Meiklemill Footbridge – trout and juvenile salmon numbers both good, eels and sticklebacks also found.

Fish surveys on the Kelly, Keithfield and Raxton Burns (2015)


Following improvement to upstream fish passage at the outflow of Haddo Lake in Haddo Country Park, River Ythan Trust volunteers led by Sandy Milne, the Ythan Salmon Fishery Board Superintendent, carried out an electrofishing exercise on the Kelly/Keithfield/Raxton burns – the main object was to establish the location and presence/absence of juvenile salmon.


Surveys were carried out at four sites - one in the Kelly Burn 175 metres below the outflow at Haddo lake, two on the Raxton Burn, one 165 metres below Morgan’s Hill Bridge, one just downstream of Bridge of Thornroan and one on the Keithfield Burn 25 metres upstream of the bridge at Mains of Haddo.


Although trout were found to be at all sites, no juvenile salmon were found.

Fish surveys on the Kelly, Keithfield and Raxton Burns (2011)


In 2011 an electrofishing survey was carried out on behalf of the River Ythan Trust on the Kelly/Keithfield/Raxton burns by the Deveron, Bogie and Isla Rivers Charitable Trust – the main object being to establish the location and presence/absence of juvenile salmon.


Electrofishing Results Summary (Extract from report)


Kelly Burn – (D/S Fish Ladder - 100 metres U/S from Ythan confluence)

26 salmon parr found and 4 salmon fry.  3 trout fry were recorded with 1 trout parr present.


Kelly Burn – (50m D/S from bridge, U/S Kelly fish ladder)

3 trout fry and an individual trout parr of 146mm were captured.  No salmon present.


Kelly Burn – (100m D/S of Haddo Lake)

1 salmon fry and 2 salmon parr were recorded.  Trout were more abundant with 1 fry and 6 parr.


Kelly Burn – (200m D/S of Haddo Lake)

4 salmon fry were recorded and no parr.  2 trout fry and 4 trout parr found.


Kelly Burn – (20m D/S Junction of Raxton & Keithfield)

5 trout fry found and 12 trout parr. No salmon present.


Keithfield Burn – (30m U/S of confluence with Raxton)

4 trout fry captured and 9 trout parr. No salmon present.


Raxton Burn – (50m u/s of confluence with Keithfield)

15 trout fry and 8 trout parr present.


Raxton Burn – (U/S of road bridge alongside farm track)

25 trout fry and 9 trout parr caught. No salmon present.


Keithfield Burn – (D/S of Keithfield lake)

11 trout fry and 1 trout parr present. No salmon present.


Apart from Kelly burn the remaining sites surveyed upstream showed poor or absent salmon production. It is noted that some salmon juveniles were found below the outflow and falls at Haddo Lake in 2005 and 2008, but in all other previous electrofishing surveys (1996 and 2002 – 2008) no salmon juveniles were found above that point.

Fish survey by the Scottish Environment Protection Agency (SEPA) (2010)


Ythan main stem above Towie Barclay Castle – trout present but in poor numbers, juvenile salmon present but in poor numbers, a few lampreys found.


Ythan main stem Newmill Bridge Auchterless – trout and juvenile salmon present, both in moderate numbers, lampreys also found.


Tifty/Skeugh near Monks Burn – trout and juvenile salmon present, both in moderate numbers.

Fish surveys by Sandy Milne, former river superintendent for the Ythan District Salmon Fishery Board (2002-08 and 2014)


These surveys were mainly to establish the presence/absence of trout and juvenile salmon.


On each of the 123 sites surveyed over this period, trout were found to be present, of the 123 sites surveyed over this period, 57 were found to have juvenile salmon.


The most comprehensive survey was carried out in 2003, where juvenile salmon were found on sites in the following waterways – Ythan, Fordoun, Stonehouse, Forvie, Ebrie, Sessnie (Cessnie), Little Water, Bronie, Youlie, Auchmacoy, Water of Cruden and Laeca.


Post 2003 the amount of electrofishing carried out has been less comprehensive.

Survey of Atlantic Salmon and Brown Trout populations of selected tributaries within the River Ythan catchment (1996)


By Isla Martin and the Scottish Conservation Projects Trust


Brief extract from the survey report


This survey and report prepared by the Scottish Conservation Projects Trust was commissioned by the Ythan District Salmon Fishery Board. It describes the results of an electrofishing survey carried out on several selected tributaries of the River Ythan in June and July 1996. A total of 59 sites (roughly 1002 each) were surveyed on the following burns: Ebrie, Ythan, Fordoun, Little Water, Bronie, Sessnie (Cessnie), Youlie, Kingsford, Raxton, Auchmacoy, Forvie, Tarty, Foveran and Keithfield.


The survey was aimed to determine the relative abundance of populations of juvenile Atlantic salmon (Salmo Salar) and Brown trout (Salmo trutta) within these burns.


All sites contained  Brown trout; juvenile Atlantic salmon were found at 32 survey sites – mainly in the  Ebrie, Ythan, Fordoun ,Little Water, Bronie, Youlie and Sessnie (Cessnie).


The most productive sites for Atlantic salmon were found on the Ythan, the Little Water, the Ebrie and Fordoun.


Other fish species found included Brook lamprey, Eel, Flounder and Stickleback (3 spined).


Juvenile Atlantic salmon tend to be found in faster flowing, shallower riffle areas of streams. Brown trout tend to prefer the slower flowing, deeper areas. An availability of overhead cover in the form of vegetation, turbulent water and suitable stream substrate is beneficial to both species as is good riparian vegetation to support stream food chains. A varied substrate with mean diameter greater than 16 mm is preferred.