Established in 2014, our experts utilise advanced fish survey methodology and techniques for comprehensive conservation and protection efforts to contribute to the sustainability of aquatic ecosystems. 

Fish Survey Conservation 

There is a diverse range of fish species within UK freshwater, with differing levels of protection and protected status. 

Despite their mobile nature, and supposedly illusive nature, fish can be surveyed and captured through a wide array of techniques. At RammSanderson we can carry out a fish survey and mitigation techniques to aid development as well as monitor watercourses and fish stocks. 

The Environment Agency restricts works that are likely to impact the river, either directly or via secondary impacts such as siltation, vibration, or pollution, to outside of the breeding season.  

In the case of Salmonid rivers, this period is between 16 June and 30 September, meaning no work can take place outside of this window. 

Fish survey conservation

Fish Depletion and Fish Sampling Surveys

It is often necessary to perform a fish survey that aims to identify the fish species present, or likely absent, in a particular area. This can help to inform future decisions on specific methodology/mitigation, and/or enhancement. 

Fish species like eel and lamprey offer higher levels of protection than other species such as Chubb or Gudgeon or may highlight invasive species such as Zander. As such, different species may garner differing approaches. 

One way of achieving this is by deploying stop nets as part of a Fish Depletion Survey, up and downstream on a river reach. The gap between is then fished until all fish are caught, recorded, and returned downstream. 

During our fish survey, all fish are identified, measured, and counted before being returned to the body of water they came from, downstream. Other ways of performing sampling of fish species presence may include seine or fyke netting in open water bodies such as lakes or reservoirs, or electrofishing small sections of waterbodies/watercourses to get a quick idea of species composition. 

However, we are also able to employ chemical testing, such as metabarcoding eDNA, which can be used to get species diversity and abundance, without carrying out a physical fish survey.


Fish Survey Techniques and Rescue Surveys 

RammSanderson has performed fish rescue surveys on a variety of projects from temporary dammed watercourses to on-site ponds. All fish are identified, measured, and counted before being returned to the body of water they came from, downstream, or to a suitably identified receptor. 

Below is a list of specific fishing techniques that we can deploy:

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RammSanderson has access to specialist Electrofishing survey equipment for use during our fish survey. Electrofishing uses electrical currents to temporarily “stun” fish. 

These fish are then netted and moved to “recovery” containers on the riverbank and are released back to a safe section of the watercourse/body or appropriate receptor, after being identified, measured, and counted. 

Electrofishing, when performed by a suitably qualified surveyor, can be a safe and efficient way to survey/move many fish. It also has the added benefit of working well with harder-to-access features. 

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Metabarcoding eDNA 

Metabarcoding eDNA is a state-of-the-art, non-invasive fish survey method used to capture and qualify fish presence within a water body. It can detail not only the species present but also the abundance of the species through the amount of eDNA sequence hits that are discovered. 

As DNA moves with the water, eDNA will capture the presence upstream of the site, and as such this should be factored into a fish survey when sampling moving water courses.

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Seine Netting 

Seine netting is the use of a large net, dragged along the bottom around a group of fish. 

Utilising multiple people at the same time, seine netting enables fish to be rounded up, without stunning them via electrofishing, or hooking them as per the conventional method. 

Seine netting is best deployed during a fish survey on larger waterbodies with flat beds.

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Stop Netting 

Stop netting is a method of cordoning a section of a watercourse without the need for a dam structure.

Instead, nets are hung at the upstream and downstream ends of the river with fish caught from the middle using another method, usually seine netting or electrofishing. 

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Fyke Netting 

Fyke nets are long cylindrical nets that can be pulled or staked into place. 

They are commonly used to sample fish abundance rather than being used to completely remove fish from one area. 

Due to their smaller size, they can be pulled and dragged from a boat and as such can be useful to fish large water bodies such as lakes or rivers. 

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Fish Rescue Surveys

In all cases, it is important to ensure works do not impact fish, as this could cause mass kill events, impact spawning ground, or reduce habitat suitability. 

*Fish rescue surveys are a way to save/move a large quantity of fish quickly, using specialist techniques whilst the water body is drained. This may be needed when using a temporary dam to dry and then cross a river, to drain down a pond or lake, or before works within the wetted channel. 

This often includes a combination of Electrofishing as well as seine netting, with seine netting used to catch most of the fish with reduced stress impact on the fish, with electrofishing used to pry fish out of hard-to-reach areas, or locations with uneven “snaggy” beds. 

*The Environment Agency must be consulted at all stages of fish rescue.  Movement to a receptor pond off-site will likely require further permitting and extra measures such as fish health checks. RammSanderson can carry out this process to ensure peace of mind when taking on these often complex jobs. 

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Boat Surveys 

Watercourses, lakes, and wetlands often harbour protected and important species, and therefore require a detailed fish survey to identify their presence. 

Where access is hindered, often by dense scrub, land access constraints, or steep banks, a fish survey may need to be undertaken by boat to enable our surveyors to get the best results for our clients. 

Boat surveys are led by a qualified lead who has completed a British Canoeing Paddle Sport Safety and Rescue Course, ensuring safety and efficiency during surveys. 

RammSanderson deploys watercraft in conditions where normal bankside access is hindered or where the size of the watercourse limits access via foot. 

We can undertake the following fish survey services using our fleet of boats:

  • Habitat surveys and Geomorphology
  • Fish Suitability Assessments
  • Fish Presence or likely absence survey
  • Fish Rescue
  • Crayfish
  • Otter and Water Vole
  • Macrophyte survey
  • Flow monitoring.

Why Choose RammSanderson for Fish Survey and Rescue Survey Services?

With over 20 years of experience, our ecological experts will work closely with you to ensure you receive a comprehensive Fish Survey using state-of-the-art technology and techniques.

We have a proven track record of reliability and accuracy and understand the importance of ensuring sustainability and the protection of water-dependent wildlife.  

RammSanderson has a team of experienced consultants ready to carry out Fish Survey and Rescue Survey Services. Get in touch today!