Electrifying activities

Victoria Franklin – Conservation Trainee

Last week some National Park Volunteers (all fully trained) have finally been able to carry out the first electro fishing surveys this year along the River Esk. Delays had been caused by the weather.

The priority are sites up and downstream of the Sewage Treatment Works (STW) and one Combined Sewer Overflow (CSO) in the upper catchment. The first day of surveying was at Commondale.

The concept of electro fishing is to collect samples of fish living within the river, the higher the fish count the healthier the river should be. This will also show the type of fish living in our rivers, the cleanliness of the river and theoretically what the invertebrate population is like along that stretch of river.

The river levels had settled down by Thursday meaning the water was back to a slow flow and all the previous rain had made the water clear giving the perfect conditions for electro fishing.

We fished the river in two 50m sections, one upstream and one downstream of water treatment works. This was done using a zig zag motion to ensure that no area was left unfished. Each 50m section was fished three times to ensure a fair population of fish were caught.

Esk electro fishing October 2019. Copyright NYMNPA.

The equipment used to stun the fish is called an electro fisher and consists of a positive charge the anode at the front and a negative charge called the cathode which trails along the back. These are both attached to a battery which is worn by the person conducting the fishing, today it was Volunteer Paul. Both the anode and the cathode must be in the water to cause an electro charge which is what stuns the fish, but don’t worry rubber thigh waders were worn by everyone so the electro pulse did not affect us humans like it did the fish. The rest of us were in charge of catching the stunned fish in nets alongside the anode, which is harder than it looks as the fish soon spring back to life! They are then transferred into a bucket from the nets.

Esk electro fishing October 2019. Copyright NYMNPA.

We set the voltage output at 150- 200 volts which is enough to temporarily stun the fish making them easier to catch in the net. Once the section of river has been fished the data collection begins. The fish are identified – on this day we found 57 trout downstream and 104 upstream with the largest being 180mm and the smallest recorded at 52mm. The information collected will now be analysed before being sent onto Yorkshire Water, they will then compare this with the other locations which are due to be fished over the next few weeks, and that will all help inform management of their sites as necessary.

An amazing day was had by all the volunteers and staff that attended. More data collection will happen in the next few weeks on different sites along the Esk.

Esk electro fishing October 2019 - small trout. Copyright NYMNPA.

Big Thank You’s

Kate Bailey – Catchment Partnership Officer

The BIFFA funded project ‘Restoring Freshwater Mussel Rivers in England’ came to an end in 2018. We were involved because of the River Esk in the north of the National Park. The £300,000 made available helped towards safeguarding Yorkshire’s last remaining population of Freshwater pearl mussels (Margaritifera margaritifera).Image of the River Esk, August 2013. Copyright Sam Jones, NYMNPA.

A huge amount of work was achieved in the Upper Esk catchment during the three year period of this project, working closely with the farming community to address diffuse pollution from agriculture. Pollution including sedimentation detrimentally affects water quality and therefore impacts on aquatic species like the mussels.

For most of its three years the project was led by Simon Hirst, our River Esk Project Officer. Simon worked with 38 land managers in the Upper Esk catchment delivering improvement works to help keep pollution including sedimentation out of the river and its tributaries. This has meant:

  • Over 8km of riparian fencing installed
    This helps stabilise the river banks and creates buffer strips to reduce the amount of runoff from fields getting into watercourses, as well as providing rough habitat along the river corridor for insects which are so important for fish, birds and small mammals.
  • 650 trees planted along the river banks of the Esk and its tributaries
    The majority of which were planted by our dedicated River Esk Volunteer Group.
    Trees help stabilise the banks and so. like with the fencing, reduce sedimentation.
  • 34 alternative watering points installed
    This is to reduce poaching in fields and along the river banks, and to keep stock and their effluent out of a watercourse.
  • Approximately 5.5km of riverbank re-vegetated with woodrush planting
    Another 130m of river bank was stabilised using hazel/willow whips. Re-vegetation helps stabilises the river banks
  • Over 500m of guttering and downpipe installed on farm buildings
    To capture clean water before it gets onto the ground, picks up nutrients and sediment, and then runs into a watercourse.
  • 1,237 m3 of concreting in farm yards.
    The new surface is profiled to collect dirty water before it can enter a nearby watercourse.

Big Thank You to Biffa for supporting the Restoring Freshwater Mussel Rivers in England project.

Big Thank You to all the local land managers who worked alongside Simon on the Esk, contributing a lot  of their own time and capital to complete these improvement works.

Big Thank You to our dedicated Mussel Volunteers who have played such a vital role in this delivery project, and all the other volunteers that helped out like the Explorer Club and the 1st Marston Moor Scout Group.

River Esk Volunteers, taking a well earned rest. Copyright NYMNPA.

And one more Big Thank You to Simon Hirst. Last year the North York Moors National Park had to say goodbye to Simon because he moved on to a new role working on the River Holme in Huddersfield. His enthusiasm and knowledge will be greatly missed by us and the Esk’s Freshwater pearl mussels.

Electric expeditions

People's Postcode Lottery logoUPDATE

The Yorkshire Esk Rivers Trust have recently been awarded a grant from the Postcode Local Trust, a grant giving charity funded entirely by players of the People’s Postcode Lottery. This grant means we can purchase our own electric fishing equipment and train more volunteers to undertake surveys in 2018. If you’re interested in getting involved with surveys – please contact Kate

.

Kate Bailey – Catchment Partnership Officer

Electric fishing is a method used to determine fish populations in watercourses, commonly carried out by organisations such as the Environment Agency and the various River Trusts. Sites across the River Esk catchment up in the north of the North York Moors have been monitored using this technique over the past 20+ years as a way of estimating juvenile fish populations. In the last five years an increased number of sites have been surveyed along the Esk and we’ve managed to gain a better understanding of fish population changes.

This summer we took the chance to learn the technique ourselves. Simon Hirst our River Esk Project Officer, six keen volunteers and I went on a fully certified electric fishing course. Our new specialist team is made up of local anglers and existing River Esk Volunteers, all of whom care about the river and want to safeguard the species that live in it.

The two day course was essential to ensure our ‘in house’ monitoring can be carried out safely and to make sure the information we collect is scientifically robust so we can draw conclusions from it.

Methodology

During an electric fishing survey an electrical current is sent through the water which temporarily stuns the fish enabling them to be easily caught in nets. To produce an electrical current one team member wears the backpack which holds a battery and control box. A cathode trails behind the backpack resting in the water and the operator holds a pole with a metal ring on the end (anode). Once the operator places the anode in the water and turns the system on, the electrical circuit is complete and a small current passes through the water. The equipment has multiple safety features to ensure surveys can be carried out safely for all involved – that’s the fish, the operator and all the other team members in the water and on the bankside.

Two or three team members follow behind the operator with the nets and buckets ready to quickly remove the stunned fish from the river.

September 2017 - Electric Fishing in Esk. Copyright NYMNPA.

Once caught, the stunned fish are transferred into a large holding tank on the bankside. Each fish is measured using a special measuring board – this helps us estimate the relative age of the fish. The size and species is noted down and the fish is then released back into the river as quickly as possible.

September 2017 - Electric Fishing in Esk. Copyright NYMNPA.

Sites are identified – usually an approximately 50 metre stretch of river – and the team enters the water at the downstream end and walks upstream fishing as they go until they reach the top of the site. It is useful to fish up to a feature in the river, for example a natural barrier like a riffle, to ensure the greatest percentage of fish can be caught. If the end of the site was situated in the middle of a pool, for example, the fish would be driven beyond the far end and hence not be recorded.

Once the site has been fished, it also needs to be measured – this allows us to work out species density (i.e. the number of fish per unit area). We measure the channel width at 10 metre intervals and calculate an average width. This average width is multiplied by the length of river surveyed to give us a total area of river fished! Fish densities are usually recorded as the number of fish per 100 metres2

September 2017 - Electric Fishing in Esk. Copyright NYMNPA.

Health & Safety

Fish welfare (and the welfare of our volunteers and us) is extremely important, there is little point in measuring fish populations to help sustain numbers if we end up with dead fish. When electric fishing is carried out correctly this methodology does not harm the fish. As part of the training we learnt how to set the control box to the correct settings to ensure the electrical current will temporarily stun the fish but will not cause any damage. This is determined by the electrical conductivity of the water – a reading is taken before carrying out the surveys.  It is important to temporarily keep the fish in a large holding tank in the shade to ensure there is sufficient oxygen for them and that the water temperature does not increase too much, and we release the fish back to the river as soon as possible.

Fish aside, all team members who are in the river must ensure they are fully insulated (e.g. rubber chest waders) and must not put their hands into the water when the backpack is switched on. Prior to undertaking a survey each stretch of watercourse is checked for hazards and a site risk assessment produced. This is to make sure there are no ‘nasty’ surprises (such as deep holes!) when the team enter the water.

Why

Electric fishing is a really good way of estimating fish populations and this is extremely important on the River Esk. Atlantic salmon is a species that is struggling due to a wide variety of issues including water quality and habitat issues, barriers to fish migration and poor survival rates at sea. Monitoring juvenile numbers across the Esk every year will help to highlight areas where these issues are magnified and can therefore help target the conservation work we’re undertaking in the catchment to improve water quality and riparian habitats.

Our electric fishing team were out and about in the catchment in the autumn surveying six specific sites. It proved a success – the surveyed fish were released back and all the volunteers survived. Species recorded included Brown trout (Salmo trutta), Atlantic salmon (Salmo salar), Stone loach (Barbatula barbatula), European eel (Anguilla Anguilla), Bullhead (Cottus gobio) and Brook lamprey (Lampetra planeri). Overall our results showed healthy fish populations at each site, although as expected relatively low numbers of Atlantic salmon were found.

We plan to monitor juvenile fish populations annually in September, to build up our understanding of the local status of the Atlantic salmon and the other species found in the Esk.

Cosseting coastal streams

John Beech – Land Management Adviser

Over the winter months and tree planting season as part of our on-going quest to promote habitat connectivity in the North York Moors we’ve been working on coastal streams and linking up bankside (riparian) woodlands. There are a number of these coastal streams that run down from the east edges of the moorland plateau and don’t merge with a river but instead each continue east and end up running into the North Sea along the North York Moors coast.

Some of these coastal stream catchments have persistent water quality issues. By judicious land management and habitat stimulus we can combine the two objectives (extend habitat connectivity AND improve water quality) and make best use of available knowledge, skills and resources. Stabilising and fencing off banks to minimise sedimentation and to keep stock out of the water, along with buffering agricultural run-off, can have extensive impacts downstream and on the coast where the streams meets the sea.

Bankside tree planting underway - NYMNPA

This has been a real partnership effort. The National Park Authority’s northern work force – with any luck, skilled environmental workers for the future, the Northern Apprentice Team – strove through the mud and planted a good mix of native trees and shrubs, whilst land managers installed the fencing. Together we managed to fence over 600 metres of land and plant around 1,000 trees in gaps alongside the watercourses.

View of tree planting and fencing work near Mickleby - NYMNPA

Thanks to everyone who contributed to this work, not least the Environment Agency who paid for materials through their Tree Mitigation Programme.

This isn’t a solution in itself, but it’s part of an expanding effort to tackle water quality problems. For information on Defra’s available advice and grants – see Catchment Sensitive Farming.