Natural England Conservation Advice for Marine Protected Areas
Medway Estuary MCZ

Natural England guidance

This site collection contains Natural England’s conservation advice for this site. It fulfils Natural England’s responsibility under the Marine and Coastal Access Act 2009, to give advice on how to further the conservation objectives for the site, identify the activities that are capable of affecting the designated features and the processes which they are dependent upon.

Natural England's conservation advice for this site is made up of a number of components. You will need to consider: Additional information for consideration:

Site information

Site name: Medway Estuary MCZ
Designation type: MCZ
Site identification: UKMCZ0011
Latest designation date: 31 May 2019
Designated features
(click to see site specific description):

General information on the site features:
The general information on the designated features from the MCZ features catalogue is useful for understanding the designated features, and should be used in conjunction with the site specific information.
Designated area (ha): 5995.84
Moderation/boundary changes: The site was designated on 12 December 2013. Smelt (Osmerus eperlanus) was added as a protected feature on 31 May 2019. For smelt only the upstream boundary of the site been extended to the tidal limit by Allington Lock. For all other features the boundary remains unchanged and is adjacent to Cuxton and Borstal.
Component Sites of Special Scientific Interest (SSSI):
Overlapping Protected Areas:

Last updated: 13th September 2019

Background information and geography

The Medway Estuary Marine Conservation Zone (MCZ) is an inshore site located on the Kent coast. Forming a single tidal system with the Swale, the Medway joins the Thames Estuary at its mouth between the Isle of Grain and Sheerness. The MCZ boundary begins near Rochester and extends seawards into the mouth and encompasses everything up to mean high water. The upper reaches of the site are narrow, this leads to an over wide middle section containing some low lying islands. The estuary mouth is narrow and constrained.

Within the site there is a complex and dynamic ecosystem. The mix of fresh and sea waters, combined with the tidal movement, create changing levels of salinity and nutrients providing a fertile environment for wildlife, particularly invertebrates, fish and birds.

Surrounded by low lying intertidal areas of saltmarsh and mudflat, which are conserved under other designations, the broad-scale habitat features of this MCZ help to complete the protection of habitats in the Medway. In particular, the subtidal channel is now afforded some protection. Tentacled lagoon-worm, estuarine rocky habitats and intertidal rock features were noted during the selection of the site for designation as being relatively rare within the South East.

Site maps

Use the MAGIC website to see site maps, including habitats, species and other marine designations.

These maps are based on best available evidence, there are some caveats associated with the maps on MAGIC.

Conservation objectives

The site’s conservation objectives apply to the Marine Conservation Zone and the individual species and / or habitat for which the site has been designated (the “Designated features” listed below). The conservation objective of the zone is that the protected features:

  1. are maintained in favourable condition if they are already in favourable condition
  2. be brought into favourable condition if they are not already in favourable condition

For each protected feature favourable condition means that, within a zone:

  1. its extent is stable or increasing
  2. its structure and function, its quality and the composition of its characteristic biological communities (including the diversity and abundance of the species forming part of or inhabiting the habitat) are sufficient to ensure that its condition remains healthy and does not deteriorate

Any temporary deterioration in condition is to be disregarded if the habitat is sufficiently healthy and resilient to enable its recovery.

For each species of marine fauna, favourable condition means that the population within a zone is supported in numbers which enable it to thrive, by maintaining:

  1. the quality and quantity of its habitat
  2. the number, age and sex ratio of its population

Any temporary reduction of numbers of a species is to be disregarded if the population is sufficiently thriving and resilient to enable its recovery.

Any alteration to a feature brought about entirely by natural processes is to be disregarded when determining whether a protected feature is in favourable condition.

This should be read in conjunction with the accompanying supplementary advice section, which provides more detailed advice and information to help achieve the objectives set out above.

Designated features:

  • Estuarine rocky habitats
  • Intertidal mixed sediments (A2.4)
  • Intertidal sand and muddy sand (A2.2)
  • Low energy intertidal rock (A1.3)
  • Peat and clay exposures
  • Smelt (Osmerus eperlanus)
  • Subtidal coarse sediment (A5.1)
  • Subtidal mud (A5.3)
  • Subtidal sand (A5.2)
  • Tentacled lagoon-worm, Alkmaria romijni

Supplementary Advice on Conservation Objectives

See supplementary advice on conservation objectives for this site, which aim to describe the range of ecological attributes that are most likely to contribute to a site’s overall integrity.

Last updated: 13th September 2019

Advice on Operations

See the advice on operations for this site to view information on the sensitivity of features in this site to the pressures exerted by different activities.

Last updated: 13th March 2020

Feature Condition

In 2016, Natural England trialled and rolled out a new Marine Protected Area (MPA) condition assessment methodology that provides robust results and information on the condition of marine features designated within MPAs in England. With guidance from National teams and using all available evidence and condition monitoring data, Area Teams conduct these assessments following a standardised approach that assesses if the feature and sub feature conservation targets set for each MPA have been met.

To date, condition assessments have been completed for a number of features in a range of marine Special Areas of Conservation (SACs) by the National and Area Teams. Further marine habitat features in SACs and other MPAs will continue to be assessed in the future. The new method can now also be applied to complete habitat and species condition assessments for other MPAs in England, whilst still meeting the different processes in place to report on the results of condition of features in Marine Conservation Zones (MCZs) and Special Protection Areas (SPAs). Different processes are currently in place to decide and report on the condition of non-marine habitat and species features of SACs.

The main part of the assessment process is directly undertaken and stored here on Natural England’s Designated Sites View. The details for the most recent assessments of this site can be found here.

Management measures

If you are carrying out an environmental assessment, planning an operation or assessing an operation or proposal, it is important to consult with the following organisations where applicable. To find out if any management measures, byelaws or other restrictions apply to your activity see the management measure page or you can use the following links for more information.

The Marine Management Organisation license, regulate and plan marine activities in the seas around England and Wales so that they’re carried out in a sustainable way.
Environment Agency are responsible for regulating major industry and waste, water quality and resources, fisheries, inland river, estuary and harbour navigations, conservation and ecology.
Offshore Petroleum Regulator for the Environment and Decommissioning (OPRED) regulates oil and gas, CCS and gas storage activities in the marine environment.

Further information

For further information relating to this designated site you can refer to the following resources:
Site specific information: Other information:
For further information about this site contact: Natural England enquiries Telephone: 0300 060 3900. Email: