4f4c4942-4343-5764-6473-313130323039 English Natural Resources Wales (NRW) Maes-y-Ffynnon, Penrhosgarnedd, Bangor, Gwynedd, LL57 2DW, Wales enquiries@naturalresourceswales.gov.uk http://naturalresources.wales/?lang=en 2026-03-03T14:39:22.488Z NRW 1.0 wel British National Grid (EPSG::27700) Establishment of a Permanent Monitoring Site at Mid Channel Rocks, Milford Haven Establishment of a Permanent Monitoring Site at Mid Channel Rocks, Milford Haven Sefydlu Safle Monitro Parhaol yn y Mid Channel Rocks, Aberdaugleddau 1998-06-30 NRW_DS110209 Data from a study undertaken to establish a permanent monitoring site on Mid Channel Rocks, Milford Haven. The work was commissioned following the grounding of the Sea Empress oil tanker on the Mid Channel Rocks, Milford Haven on February 15th 1996. On the four days following the grounding, the tanker remained in the immediate vicinity of these rocks, grounding and floating free several times. An estimated 70,000 tonnes of oil were spilled within one nautical mile of the Mid-Channel Rocks. A considerable volume of dispersant was applied from the air in the nearby area. This is expected to have led to significantly elevated hydrocarbon levels in the water column, possibly including the more toxic oil fractions where fresh oil was dispersed. The objectives of this project were to establish a permanent sublittoral monitoring site at a rock substrate location close to the source of the spilled oil and which was amongst the most likely to have been subjected to elevated water column hydrocarbon load and to undertake a baseline survey to document epibenthic rock community and species composition, diversity, richness and condition. Data was captured in order to establish a permanent sublittoral monitoring site at a rock substrate location close to the source of the spilled oil and to undertake a baseline survey to document epibenthic rock community and species composition, diversity, richness and condition. Data from a study undertaken to establish a permanent monitoring site on Mid Channel Rocks, Milford Haven. The work was commissioned following the grounding of the Sea Empress oil tanker on the Mid Channel Rocks, Milford Haven on February 15th 1996. On the four days following the grounding, the tanker remained in the immediate vicinity of these rocks, grounding and floating free several times. An estimated 70,000 tonnes of oil were spilled within one nautical mile of the Mid-Channel Rocks. A considerable volume of dispersant was applied from the air in the nearby area. This is expected to have led to significantly elevated hydrocarbon levels in the water column, possibly including the more toxic oil fractions where fresh oil was dispersed. The objectives of this project were to establish a permanent sublittoral monitoring site at a rock substrate location close to the source of the spilled oil and which was amongst the most likely to have been subjected to elevated water column hydrocarbon load and to undertake a baseline survey to document epibenthic rock community and species composition, diversity, richness and condition. Data was captured in order to establish a permanent sublittoral monitoring site at a rock substrate location close to the source of the spilled oil and to undertake a baseline survey to document epibenthic rock community and species composition, diversity, richness and condition. Natural Resources Wales (NRW) Maes-y-Ffynnon, Penrhosgarnedd, Bangor, Gwynedd, LL57 2DW, Wales enquiries@naturalresourceswales.gov.uk http://naturalresources.wales/?lang=en Natural Resources Wales (NRW) Maes-y-Ffynnon, Penrhosgarnedd, Bangor, Gwynedd, LL57 2DW, Wales enquiries@naturalresourceswales.gov.uk http://naturalresources.wales/?lang=en MarineSeen Estuary Cottage, Bentlass, Hundleton, Pembrokeshire, SA71 5RN, Wales fbunker@marineseen.com http://www.marineseen.com/ Subsea Survey 13-14 Merlins Cross, Lower Lamphey Road, Pembroke, Pembrokeshire, SA71 4AG 100662.2000@compuserve.com <!__ Nowebsite __!> Natural Resources Wales (NRW) Maes-y-Ffynnon, Penrhosgarnedd, Bangor, Gwynedd, LL57 2DW, Wales enquiries@naturalresourceswales.gov.uk http://naturalresources.wales/?lang=en Species distribution GEMET - INSPIRE themes, version 1.0 2008-06-01 geonetwork.thesaurus.external.theme.httpinspireeceuropaeutheme-theme Milford Haven Sea Empress oil oil tankers dispersant oil dispersants hydrocarbon analysis hydrocarbons marine biology (subtidal biology) (littoral biology) (sublittoral biology)(intertidal biology)(see also seashore) marine surveys (intertidal & subtidal surveys) (littoral survey) (sublittoral surveys) (bathymetric survey) (see also marine monitoring and MNCR) rock communities baseline survey marine and freshwater inventory permanent monitoring site Mid Channel Rocks toxic oil fractions sublittoral monitoring site water column hydrocarbon load epibenthic rock community diversity richness condition NRW Thesaurus 2023-12-31 geonetwork.thesaurus.local.theme.converted_nrw-keywords Pollution events Zoobenthos generic abundance Zoobenthos taxonomy-related counts SeaDataNet Parameter Discovery Vocabulary 2021-01-06 geonetwork.thesaurus.external.theme.rdf+xml Integrated Public Sector Vocabulary 2013-04-03 geonetwork.thesaurus.external.theme.subjects NRW SMNR Vocabulary 2023-12-27 geonetwork.thesaurus.local.theme.converted_nrw-smnr-keywords There are no access restrictions to this data. NRW may release, publish or disseminate it freely. no limitations © CNC/NRW There are no use restrictions on this data. Recipients may re-use, reproduce, disseminate this data free of charge in any format or medium, provided they do so accurately, acknowledging both the source and NRW's copyright, and do not use it in a misleading context. It is the recipient's responsibility to ensure the data is fit for the intended purpose, that dissemination or publishing does not result in duplication, and that it is fairly interpreted. Advice on interpretation should be sought where required. To avoid re-using old data, users should periodically obtain the latest version from the original source. English environment biota SeaVoX Vertical Co-ordinate Coverages 2021-01-06 benthic boundary layer Wales (WLS) -5.31679525 -5.31679525 51.48525748 51.83640018 1997-07-17 1997-07-28 The establishment of a permanent monitoring site at Mid Channel Rocks, Milford Haven Documents Report (MS Word and PDF-format) Postscript (MS Word) Commission Regulation (EU) No 1089/2010 of 23 November 2010 implementing Directive 2007/2/EC of the European Parliament and of the Council as regards interoperability of spatial data sets and services 2010-12-08 This dataset has not been assessed for conformance to the referenced INSPIRE regulation. false Divers using standard SCUBA apparatus carried out the survey work. Procedures were carried out under HSE DOW 1981 regulations and JNCC diving rules (Holt, 1993). Once the study sites were marked out, a variety of data collecting exercises were carried out: Community descriptions were obtained from defined areas using Marine Nature Conservation Review (MNCR) techniques. Particular rock faces were chosen which were typical of the main habitat / community types and careful studies were undertaken to list all conspicuous species present and note abundances. Counts of species in quadrats and also suction samples were undertaken at both the Lower Infralittoral and Circalittoral Study Sites. This project followed immediately on from one which surveyed selected locations along the South Pembrokeshire coast from Milford Haven to Caldey. Mid Channel Rocks was one of the sites surveyed and the work was carried out with the present monitoring study in mind. The only data associated with this project is held within the report. Divers using standard SCUBA apparatus carried out the survey work. Procedures were carried out under HSE DOW 1981 regulations and JNCC diving rules (Holt, 1993). Once the study sites were marked out, a variety of data collecting exercises were carried out: Community descriptions were obtained from defined areas using Marine Nature Conservation Review (MNCR) techniques. Particular rock faces were chosen which were typical of the main habitat / community types and careful studies were undertaken to list all conspicuous species present and note abundances. Counts of species in quadrats and also suction samples were undertaken at both the Lower Infralittoral and Circalittoral Study Sites. This project followed immediately on from one which surveyed selected locations along the South Pembrokeshire coast from Milford Haven to Caldey. Mid Channel Rocks was one of the sites surveyed and the work was carried out with the present monitoring study in mind. The only data associated with this project is held within the report.