Marine and freshwater
invertebrate surveys

There are a number of species of freshwater invertebrate that receive legal protection, such as white-clawed crayfish, medicinal leach, pearl mussel, Desmoulin’s whorl snail and southern damselfly, and may require consideration at the planning stage.

Freshwater invertebrate families and species differ in their sensitivity to a range of stresses. The presence of the range of families or species can therefore allow for accurate assessment of long-term water quality.

We have a number of in-house invertebrate specialists capable of kick, sweep and other sampling methods, identifying aquatic invertebrates and calculating indices of water quality including the Biological Monitoring Working Party (BMWP) Score, Average Score per Taxon (ASPT), LIFE and River Invertebrate Prediction and Classification System (RIVPACS).

Our in-house invertebrate specialists are licensed to conduct surveys, using the appropriate techniques and have a wealth of experience conducting surveys, interpreting the results and designing and conducting effective mitigation where appropriate.

Marine invertebrate surveys

Thomson Unicomarine handles all benthic and epibenthic survey requirements.

We have an extensive team of experienced and qualified surveyors capable of conducting intertidal and subtidal surveys using a variety of sampling gear.

Subtidal surveys

We have over 25 years of experience in conducting subtidal surveys and have Standard Operating Procedures for a wide range of subtidal survey methods including:

• Dredge
• Anchor dredge
• Day grab
• Beam Trawl (including in-situ identification)
• Van Veen grab
• Hamon grab
• Mini-Hamon grab
• Box corer / grab
• Video and stills

We own a variety of the more commonly used sampling gear and are able to respond to the diverse requirements of different surveys.

Certification

Our survey staff are fully trained and hold appropriate safety and medical certification. This includes UK Offshore Operators Association (UKOOA) medical certification as well as Basic Offshore Safety Induction and Emergency Training (BOSIET) certification. Our staff can be deployed on surveys throughout the UK and further afield.

Service scope

Our clients often require subtidal surveys to determine principal habitats and community types (biotopes) present for:

• Baseline data for environmental impact assessments (EIAs)
• Environmental monitoring
• Shoreline developments; and
• Supporting data for Marine Conservation Zones

Our surveys always take into account the clients requirements and, where necessary, the approval of the appropriate licensing authorities. We deliver surveys in the most cost-effective manner using locally-sourced vessels, and in the minimum amount of time necessary.

Once the survey is complete we can conduct all associated benthic taxonomy, particle size analysis, video and stills analysis and data analysis and reporting.

Intertidal surveys

Covering a range of habitats from salt marshes, mud flats, estuaries, rocky shores and sandy beaches, we have experience of conducting a variety of surveys in the intertidal environment.

Within the built environment, we have experience of executing surveys on sea walls, sea defences, pontoons and harbours.

Our survey design team help to design surveys appropriate to the habitat in question and using the appropriate method, whether on foot, by boat or hovercraft. Our survey team have been through appropriate internal and external training, and hold licenses for a range of protected species. Through the use of our mobile mapping devices our staff can utilise maps, and add additional data in situ.

We have conducted surveys across the whole of the UK, including many estuaries. This includes over 60 projects on the Thames - including work for the London Eye, Millenium Dome, Millenium Bridge and Tate Modern.