Initial hydroacoustic mapping of macrophyte communities in the southern end of Llyn Tegid

This dataset is made up of the results of a hydroacoustic survey to map the extent of submerged macrophyte communities and major substrate types in the southern end of Llyn Tegid. The objectives of the present part of the project were to use hydroacoustics to map the current extent of submerged macrophyte communities and major substrate types in the southern end of Llyn Tegid and to present the findings of such work at the Countryside Council for Wales Marine and Freshwater Workshop 2007. This works was undertaken as a small work package added during the summer of 2007 to a much larger project concerned with the hydroacoustic survey and translocation of the gwyniad (Coregonus lavaretus).

Dynodydd: NRW_DS110064

Teitl Amgen

Mapio hydroacwstig cychwynnol o gymunedau macroffytau ym mhen deheuol Llyn Tegid,
Initial hydroacoustic mapping of macrophyte communities in the southern end of Llyn Tegid,

Laith Metadata: English

Datganiad: Echo sounding was carried out using a BioSonics DT-X echo sounder with a 200 kHz splitbeam vertical transducer of beam angle 6.5 degrees operating under the controlling software Visual Acquisition Version 5.0.4. Throughout the surveys, data threshold was set at -130 dB, pulse rate at 5 pulses s-1, pulse width at 0.1 ms, and data recorded from a range of 0 m from the transducer. The system was deployed from a 4.8 m inflatable dinghy powered by a 25 horse power petrol outboard engine and moving at a speed of c. 1.1 m s-1, depending on wind conditions. The transducer was positioned c. 0.5 m below the surface of the water. Navigation was accomplished using a Garmin GPSMAP 60CSx Global Positioning System (GPS) with accuracy to less than 10 m, while a JRC Model DGPS212 GPS with accuracy to less than 5 m inputted location data directly to the hydroacoustic system where they were incorporated into the recorded hydroacoustic data files. Prior to the surveys, the hydroacoustic system had been calibrated using a tungsten carbide sphere of target strength (TS) -39.5 dB at a sound velocity of 1470 ms-1. Hydroacoustic surveys were undertaken between c. 20.29 and 21.34 hours on 13 August 2007 using 20 transects, each starting near the 10 m depth contour and running directly inshore to a depth of c. 1 m. Transects varied in length from c. 20 to 226 m depending on local bathymetry and hindrances to navigation in the form of semi-submerged fences or near-surface rocks.

Dyddiad cyfeirnod y set ddata (Cyhoeddiad): 2008-02-29

Ystod amser

Dyddiad cychwyn: 2007-08-13

Dyddiad gorffen: 2007-08-31

Categori pwnc

Biota

Perchennog

Snowdonia National Park Authority

National Park Office, Penrhyndeudraeth, Gwynedd, LL48 6LF, Wales

http://www.eryri-npa.gov.uk/

Perchennog

Natural Resources Wales (NRW)

Maes-y-Ffynnon, Penrhosgarnedd, Bangor, Gwynedd, LL57 2DW, Wales

http://naturalresources.wales/?lang=en

Cychwynnwr

CEH Lancaster

Lancaster Environment Centre, Library Avenue, Bailrigg, Lancaster, Lancashire, LA1 4AP

http://www.ceh.ac.uk/index.html

Rhychwant

Hyd: Wales (WLS)

Hyd: GWYNEDD - GWYNEDD

Map representing the geographic extent of the dataset

Fformat - Math a Disgrifiad

Documents Documents ()

Math

Raw data derived from the echo sounder is stored in *.dt4 format (Visual Acquisition Version 5.0.4) proprietary software would be required to view or analyse this data. Data from the laboratory examination and analysis of output from the echo sounder and GPS used in the field were analysed with Sonar5-Pro Version 5.9.7 (24.09.2007). This data was supplied as Microsoft Excel files. This report has been produced as a Microsoft Word 2000 file(s) and as an Adobe Portable Document Format version.

Ansawdd Data

Cwmpas Ansawdd: Dataset

Cydymffurfiad: 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
Eglurhad
Gradd: false

Datganiad: Echo sounding was carried out using a BioSonics DT-X echo sounder with a 200 kHz splitbeam vertical transducer of beam angle 6.5 degrees operating under the controlling software Visual Acquisition Version 5.0.4. Throughout the surveys, data threshold was set at -130 dB, pulse rate at 5 pulses s-1, pulse width at 0.1 ms, and data recorded from a range of 0 m from the transducer. The system was deployed from a 4.8 m inflatable dinghy powered by a 25 horse power petrol outboard engine and moving at a speed of c. 1.1 m s-1, depending on wind conditions. The transducer was positioned c. 0.5 m below the surface of the water. Navigation was accomplished using a Garmin GPSMAP 60CSx Global Positioning System (GPS) with accuracy to less than 10 m, while a JRC Model DGPS212 GPS with accuracy to less than 5 m inputted location data directly to the hydroacoustic system where they were incorporated into the recorded hydroacoustic data files. Prior to the surveys, the hydroacoustic system had been calibrated using a tungsten carbide sphere of target strength (TS) -39.5 dB at a sound velocity of 1470 ms-1. Hydroacoustic surveys were undertaken between c. 20.29 and 21.34 hours on 13 August 2007 using 20 transects, each starting near the 10 m depth contour and running directly inshore to a depth of c. 1 m. Transects varied in length from c. 20 to 226 m depending on local bathymetry and hindrances to navigation in the form of semi-submerged fences or near-surface rocks.

Allweddair

GEMET - INSPIRE themes, version 1.0

Species distribution

Math: Theme

Dyfyniad

Dyddiad (Cyhoeddiad): 2008-06-01

Cod: geonetwork.thesaurus.external.theme.httpinspireeceuropaeutheme-theme

Allweddair

NRW Thesaurus

Llyn Tegid
macrophyte surveys
macrophytes
hydroacoustic
marine and freshwater inventory

Math: Theme

Dyfyniad

Dyddiad (Cyhoeddiad): 2023-12-31

Cod: geonetwork.thesaurus.local.theme.converted_nrw-keywords

Cod: British National Grid (EPSG::27700)

Gwybodaeth Cynnwys

Proffil CNC

Elfennau CNC

Teitlau cysylltiedig CNC: Initial hydroacoustic mapping of macrophyte communities in the southern end of Llyn Tegid

Cyfyngiadau

Cyfyngiadau ar Fynediad a Defnydd Cyhoeddus

Math o Gyfyngiad: Other restrictions

Cyfarwyddeb Cyfyngiadau Mynediad

Cyfyngiadau: no limitations

Testun cyfyngiadau mynediad

Cyfyngiadau eraill: There are no access restrictions on this data. NRW may release, publish or disseminate it freely.

Defnyddiwch gyfyngiadau

Cyfyngiadau Defnyddio: Other restrictions

Cyfyngiadau eraill: © 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.

Metadata

Dynodydd Ffeil: 4f4c4942-4343-5764-6473-313130303634 XML

Laith Metadata: English

Math o adnodd: Dataset

Dyddiad Metadata: 2024-05-31T09:39:45.335Z

Enw Safonol Metadata: NRW

Fersiwn Metadata: 1.0

Pwynt Cyswllt

Natural Resources Wales (NRW)

Maes-y-Ffynnon, Penrhosgarnedd, Bangor, Gwynedd, LL57 2DW, Wales

http://naturalresources.wales/?lang=en

Corff Cyhoeddi

Mynediad i'r Porth

Mynediad llawn i'r porth a'r metadata.

Initial hydroacoustic mapping of macrophyte communities in the southern end of Llyn Tegid

Dull adnabod

Ystod amser

Rhychwant

Rhychwant

Dosbarthiad

Ansawdd

Ansawdd Data

Allweddeiriau

Allweddair

Dyfyniad

Allweddair

Dyfyniad

System Cyfeirio Gofodol

Cynnwys

Gwybodaeth Cynnwys

Proffil CNC

Elfennau CNC

Cyfyngiadau

Cyfyngiadau

Cyfyngiadau ar Fynediad a Defnydd Cyhoeddus

Cyfarwyddeb Cyfyngiadau Mynediad

Testun cyfyngiadau mynediad

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Metadata

Metadata

Corff Cyhoeddi