Fishery Survey

Fishery Survey

OHES offers a comprehensive suite of fishery surveys to investigate the nature of fish populations in a range of environments. Knowledge of fish populations is essential in monitoring the status of the aquatic environment, and measuring changes brought about by natural events, environmental incidents or physical habitat improvements.

We employ a range of accepted techniques to provide quantitative and qualitative fishery surveys in rivers and streams, canals, lakes and ponds, estuaries and the marine environment.

Our services include:

  • Fish population surveys
  • Targeted species surveys (e.g. eel, lamprey)
  • Juvenile fish (fry) surveys
  • Hydroacoustic fishery surveys
  • Trapping and tagging
  • Non-native invasive species surveys
  • Impingement and entrainment monitoring for abstractions
  • White-clawed crayfish surveys

Case Studies

Thames Catchment Fishery Surveys – Thames Water Drought Plan

OHES conducted a series of 30 quantitative electric fishing surveys at sites throughout the Thames Water Region as part of a water resources study being conducted by a partner organisation.

Surveys were carried out in the Oxfordshire, Surrey, Berkshire, Wiltshire, Kent and Hertfordshire and a range of coarse fish, brown trout and eel populations were identified using quantitative electric fishing surveys

Upper Thames Low Flows Fisheries Monitoring - Environment Agency

This contract was undertaken by OHES on behalf of the Environment Agency (Thames Region), and it involved a series of bi-annual fishery surveys at nine sites across four river catchments in the Upper Thames catchment in the Cotswolds. A total of 54 survey sites on the Rivers Coln, Churn and Leach and Ampney Brook were surveyed as part of this monitoring programme, using standard quantitative electric fishing techniques. The surveys were part of a long-standing monitoring project which had been in place for a total of eleven years and was part of a long term low flows investigation relating to changes in local abstraction regimes.

Fisheries & Lamprey Monitoring in North, South and West Wales

This is an ongoing, extensive fishery and lamprey survey programme which OHES has delivered on behalf of a partner organisation for Welsh Water/Dwr Cymru for several years. The study has been focussed on seven separate Welsh River catchments and the results have been fed into a wider environmental study.

The programme has included quantitative and semi-quantitative electric fishing surveys, targeted lamprey surveys, lake and river habitat assessments (including an Arctic char spawning habitat assessment and HABSCORE assessments for salmonid sites) and white-clawed crayfish surveys which have been conducted across the Wye, Afon Teifi, Afon Lwyd, Lys y Fran, Afon Taf, Lyn Cwmystradllyn and Lyn Bodlyn catchments.

A total of 85 fishery surveys and 35 targeted lamprey surveys have been completed as part of this contract.

Post-Pollution Monitoring and Remediation of a Major Fuel Spill and Rail Incident at Stewarton, Ayrshire, Network Rail

Following a major rail incident involving a bridge collapse and subsequent train derailment, fire and fuel spill, OHES were appointed to manage the incident response, environmental monitoring and remediation. Over 250,000 litres of diesel and kerosene were lost to ground and surface waters and over 27km of the River Irvine and tributaries were heavily polluted.

As part of the ecological response, our team conducted an impact assessment which included a programme of quantitative fishery surveys, aquatic macro-invertebrate surveys and an assessment of impact on otter and water vole habitat and populations. We produced a comprehensive survey report which measured the impact and recovery of the system and made recommendations for management, improvements and further study.

By Brook Crayfish Surveys and Fish Passage Assessment – Bristol Avon Rivers Trust

Surveys of white-clawed crayfish in relation to fish passage improvements in a river catchment failing its Water Framework Directive objectives for fisheries measures. The work involved the development and implementation of a series of white clawed crayfish surveys and the provision of advice and mitigation measures aimed at protecting white-clawed crayfish populations; while allowing improvements to be made to fish passage provisions.

White-clawed Crayfish Surveys at Kirkharle

As part of OHES involvement in the incident management and remediation of a significant fuel spill on the A696 at Kirkharle, our team of ecologists conducted an impact assessment and mitigation plan for the immediate remediation work to safeguard the terrestrial and aquatic environment. Local watercourses are home to populations of our native white-clawed crayfish, and surveys were conducted to ensure that this protected species was protected.

Additionally, a full programme of aquatic macro-invertebrate surveys was conducted as part of the investigation, along with terrestrial protected species surveys