Services · Specialist

Marine Intertidal Invertebrate Surveys

Coastal and estuarine development requires an understanding of the intertidal communities that will be affected. We deliver littoral survey, biotope mapping and intertidal invertebrate assessment for marine licensing and coastal EIA.

SeasonSpring/summer low tides
MethodPhase 1 littoral / biotope mapping
ApplicationMarine licensing / EIA
FrameworkMarine & Coastal Access Act

Overview

Marine intertidal invertebrate surveys characterise the biological communities of the shoreline between high and low water marks. The intertidal zone — rocky shores, sediment shores, mudflats, estuarine habitats — supports distinct assemblages of invertebrates that are highly sensitive to physical disturbance, changes in sediment dynamics and water quality alteration.

Survey methodology depends on the shore type. Rocky shores are assessed using Phase 1 littoral survey and biotope classification (following the JNCC Marine Habitat Classification), with quadrat sampling to quantify species abundance and community composition. Sediment shores are assessed using core sampling and sieve analysis. Both approaches feed into the Marine Habitat Classification for Britain and Ireland.

This work is typically required for marine licensing applications (under the Marine and Coastal Access Act 2009), Environmental Impact Assessment for coastal development, port and harbour works, sea defence construction, pipeline and cable installation and any other project that will physically affect the intertidal zone.

When you need this

  • Coastal development, sea wall or flood defence construction that will affect the intertidal zone
  • A marine licence application requires ecological baseline data
  • Port, harbour or marina works involving dredging, reclamation or coastal structures
  • Pipeline, cable or outfall installation crossing the intertidal zone
  • Environmental Impact Assessment for coastal or estuarine development

Our approach

  1. 01
    Desk study

    Review of existing survey data, Marine Recorder records, JNCC biotope maps and designated-site information for the stretch of coast.

  2. 02
    Phase 1 littoral survey

    A broad-scale survey of the intertidal zone during spring low tides, recording shore type, zonation, dominant species and biotope classification.

  3. 03
    Quantitative sampling

    Quadrat sampling on rocky shores or core sampling on sediment shores to provide species-level data, abundance estimates and community characterisation.

  4. 04
    Biotope classification and reporting

    Communities are classified to the JNCC Marine Habitat Classification standard. Results are mapped, assessed for conservation value and reported with recommendations for impact avoidance and mitigation.

Frequently asked questions

01When should intertidal surveys be carried out?+
Intertidal surveys must coincide with spring low tides to provide the maximum area of shore exposure. The best windows are typically the large spring tides between March and September. Exact dates vary year to year — we plan survey timing around tide tables.
02What is a biotope?+
A biotope is a defined habitat-community combination — a particular community of organisms associated with a particular physical environment. The JNCC Marine Habitat Classification assigns biotope codes that provide a standard language for describing and mapping intertidal and subtidal communities across the UK.
03Do I need a marine licence for coastal works?+
Most activities below mean high water springs that involve construction, dredging, deposit or removal of substances require a marine licence from the Marine Management Organisation. Intertidal ecological survey is often a condition of the licensing process.
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