4f4c4942-4343-5764-6473-313235373433 English NRW Maes-y-Ffynnon, Penrhosgarnedd, Bangor, Gwynedd, LL57 2DW, Wales enquiries@naturalresourceswales.gov.uk http://naturalresources.wales/?lang=en 2026-04-15T14:59:21.563Z NRW 1.0 wel British National Grid (EPSG:27700) KiEco Freshwater Ecology: Fish Monitoring Data - Geospatial KiEco Freshwater Ecology: Fish Monitoring Data - Geospatial Data Arolwg Pysgod Dŵr Croyw CNC NRW Freshwater Fish Surveys 2026-04-14 NRW_DS125743 Freshwater fish are used as an indicator of stock status, water and habitat quality, artificial obstacles to migration and river flow requirements due to specific life-cycle requirements. This dataset is made up of the species count and length values from the freshwater river fish surveys conducted across Wales by Natural Resources Wales and former Environment Agency Wales. These surveys are conducted as part of on-going monitoring of fish in their natural environment for legislative requirements and to meet business drivers. For the non-geospatial delimited data format please see NRW_DS125358 "KiEco Freshwater Ecology: Fish Monitoring Data". Freshwater fish are used as an indicator of stock status, water and habitat quality, artificial obstacles to migration and river flow requirements due to specific life-cycle requirements. This dataset is made up of the species count and length values from the freshwater river fish surveys conducted across Wales by Natural Resources Wales and former Environment Agency Wales. These surveys are conducted as part of on-going monitoring of fish in their natural environment for legislative requirements and to meet business drivers. For the non-geospatial delimited data format please see NRW_DS125358 "KiEco Freshwater Ecology: Fish Monitoring Data". Defnyddir pysgod dŵr croyw fel dangosydd statws stoc, ansawdd dŵr a chynefin, rhwystrau artiffisial i fudo, a gofynion llif afonydd oherwydd eu gofynion cylch bywyd penodol. Mae'r set ddata hon yn cynnwys y cyfrif rhywogaethau a’r gwerthoedd hyd o’r arolygon o bysgod mewn afonydd dŵr croyw a gynhaliwyd ledled Cymru gan Cyfoeth Naturiol Cymru a’r hyn oedd Asiantaeth yr Amgylchedd Cymru. Mae'r arolygon hyn yn cael eu cynnal fel rhan o'r gwaith parhaus o fonitro pysgod yn eu hamgylchedd naturiol ar gyfer gofynion deddfwriaethol ac i fodloni ysgogwyr busnes. 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 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 Species distribution GEMET - INSPIRE themes, version 1.0 2008-06-01 geonetwork.thesaurus.external.theme.httpinspireeceuropaeutheme-theme catchment survey electric fishing monitoring (see specific types of monitoring eg. woodland monitoring) fish (fishes) (see also specific species) NRW Thesaurus 2026-03-04 geonetwork.thesaurus.local.theme.converted_nrw-keywords There are no access restrictions on this data. NRW may release, publish or disseminate it freely. noLimitations © CNC/NRW Data may be re-used under the terms of the Open Government Licence providing it is done so, acknowledging both the source and NRW's copyright. It is the recipient's responsibility to ensure the data is fit for the intended purpose. Contains Natural Resources Wales information © Natural Resources Wales and Database Right. All rights Reserved. Open Government Licence English biota SeaVoX Vertical Co-ordinate Coverages 2021-01-06 Wales (WLS) -5.311 -2.647 51.384 53.427 1974-01-01 Geographic Information System 1 ESRI Feature Class https://datamap.gov.wales/layergroups/geonode:nrw_freshwater_fish_surveys WWW:LINK-1.0-http--link View and Download Data https://datamap.gov.wales/capabilities/layergroup/6244/?ows_service=wms OGC:WMS Web Mapping Service 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 A strict methodology is applied when sampling for freshwater river fish. There is a core network of sites which are monitored on an annual basis, and also catchment-wide surveys on a six-year rolling programme. These sites are located in habitat types suitable for the respective fish species. In addition, sites may be sampled for investigative work, or on an ad hoc basis. Sampling areas are commonly 50 metres long and the full width of the river and may embrace different flow types and substrate. For Catch Per Unit Effort (CPUE) survey strategy the effort is based on a time measurement. Electric fishing is the most commonly used sampling method, although alternative methods are available for different strategies, such as netting and trapping. Once a sample of fish is collected, they are immediately identified in the field, measured and counted and then released alive into the same section of river from where they were captured. For many of our surveys we record an NGR at the site because this acts as a central/representative location around which we collect lots of samples. An NGR is then also recorded against each of the samples to give a more accurate sampling location. Redactions Some information has be redacted to make the data openly available. This includes: Third party data Data collected for ongoing investigations Cancelled or incomplete surveys Update Frequency This data is continually update with the most surveys undertaken in the summer. Data from survey seasons is often not enter at the time of capture and can be several months before its is entered into the system. The external dataset is updated monthly to include new data, and may also contain corrections to previously published data due to quality assurance work. Information Warnings Freshwater fish survey data is available from 1974 to present. A caveat being that historical data are sporadic until 2001. This is because fish survey data collected before 2001 were often saved in local databases and not the national ones (KiEco and formerly NFPD). Fish surveys are carried out by a range of survey methods, the data from one survey is not necessarily directly comparable to another. For example, the total fish count may be based on multiple or single run surveys or Catch Per Unit Effort (CPUE) surveys. The user is recommended to check the survey method used in the data provided. We do our best to avoid data quality problems, but as these datasets reflect the data we hold, they may contain errors. A strict methodology is applied when sampling for freshwater river fish. There is a core network of sites which are monitored on an annual basis, and also catchment-wide surveys on a six-year rolling programme. These sites are located in habitat types suitable for the respective fish species. In addition, sites may be sampled for investigative work, or on an ad hoc basis. Sampling areas are commonly 50 metres long and the full width of the river and may embrace different flow types and substrate. For Catch Per Unit Effort (CPUE) survey strategy the effort is based on a time measurement. Electric fishing is the most commonly used sampling method, although alternative methods are available for different strategies, such as netting and trapping. Once a sample of fish is collected, they are immediately identified in the field, measured and counted and then released alive into the same section of river from where they were captured. For many of our surveys we record an NGR at the site because this acts as a central/representative location around which we collect lots of samples. An NGR is then also recorded against each of the samples to give a more accurate sampling location. Redactions Some information has be redacted to make the data openly available. This includes: Third party data Data collected for ongoing investigations Cancelled or incomplete surveys Update Frequency This data is continually update with the most surveys undertaken in the summer. Data from survey seasons is often not enter at the time of capture and can be several months before its is entered into the system. The external dataset is updated monthly to include new data, and may also contain corrections to previously published data due to quality assurance work. Information Warnings Freshwater fish survey data is available from 1974 to present. A caveat being that historical data are sporadic until 2001. This is because fish survey data collected before 2001 were often saved in local databases and not the national ones (KiEco and formerly NFPD). Fish surveys are carried out by a range of survey methods, the data from one survey is not necessarily directly comparable to another. For example, the total fish count may be based on multiple or single run surveys or Catch Per Unit Effort (CPUE) surveys. The user is recommended to check the survey method used in the data provided. We do our best to avoid data quality problems, but as these datasets reflect the data we hold, they may contain errors. Llinach Defnyddir methodoleg gaeth wrth samplu pysgod afonydd dŵr croyw. Mae rhwydwaith craidd o safleoedd sy'n cael eu monitro'n flynyddol, a hefyd arolygon dalgylch cyfan ar raglen dreigl o chwe blynedd. Mae'r safleoedd hyn wedi'u lleoli mewn mathau o gynefin sy'n addas ar gyfer y rhywogaethau pysgod priodol. Yn ogystal, gellir samplu safleoedd ar gyfer gwaith ymchwiliol, neu ar sail ad hoc. Mae ardaloedd samplu fel arfer yn 50 metr o hyd a lled llawn yr afon, a gallant gynnwys gwahanol fathau o lif a swbstrad. Ar gyfer strategaeth arolwg Dalfa Fesul Uned Ymdrech (CPUE), mae'r ymdrech yn seiliedig ar fesuriad amser. Pysgota trydanol yw'r dull samplu a ddefnyddir mwyaf aml, er bod dulliau amgen ar gael ar gyfer gwahanol strategaethau, megis rhwydo a thrapio. Unwaith y bydd sampl o bysgod yn cael ei chasglu, cânt eu hadnabod ar unwaith yn y maes, eu mesur a'u cyfrif, ac yna eu rhyddhau'n fyw i'r un rhan o'r afon lle cawsant eu dal. Golygiadau Mae rhywfaint o wybodaeth wedi’i golygu i sicrhau bod y data ar gael yn agored. Mae hyn yn cynnwys: Data trydydd parti Data a gasglwyd ar gyfer ymchwiliadau parhaus Arolygon wedi’u canslo neu heb eu cwblhau Amlder Diweddaru Mae'r data hwn yn cael ei ddiweddaru'n barhaus gyda'r rhan fwyaf o arolygon yn cael eu cynnal yn ystod yr haf. Yn aml, nid yw data o dymhorau arolygon yn cael eu mewnbynnu ar adeg eu cipio a gall fod sawl mis cyn iddo gael ei roi yn y system. Mae’r set ddata allanol yn cael ei diweddaru yn fisol i gynnwys data newydd, a gall hefyd gynnwys cywiriadau i ddata a gyhoeddwyd yn flaenorol oherwydd gwaith sicrhau ansawdd. Rhybuddion Gwybodaeth Mae data arolygon pysgod dŵr croyw ar gael ers 1974 hyd heddiw. Y cafeat yw bod data hanesyddol yn ysbeidiol tan 2001. Mae hyn oherwydd bod data arolygon pysgod a gasglwyd cyn 2001 yn aml yn cael ei gadw mewn cronfeydd data lleol ac nid y rhai cenedlaethol (KiEco ac NFPD gynt). Mae arolygon pysgod yn cael eu cynnal trwy amrywiaeth o ddulliau arolygu ac nid yw'r data o un arolwg o reidrwydd yn gallu cael ei gymharu yn uniongyrchol ag un arall. Er enghraifft, gall cyfanswm y cyfrif pysgod fod yn seiliedig ar arolygon lluosog neu un rhediad neu arolygon Dalfa Fesul Uned Ymdrech (CPUE). Argymhellir y defnyddiwr i wirio'r dull arolygu a ddefnyddiwyd yn y data a ddarperir. Gwnawn ein gorau i osgoi problemau ansawdd data, ond gan fod y setiau data hyn yn adlewyrchu’r data sydd gennym, gallant gynnwys gwallau. Darperir y data fel set o dablau data cysylltiedig oherwydd maint a strwythur y data. Rhagdybir dealltwriaeth sylfaenol o wyddor pysgodfeydd a chronfeydd data perthynol.