Field observations on the disturbance of grey seals in North Wales
Arsylwadau maes ar aflonyddu ar forloi llwyd yng Ngogledd Cymru

  • English
  • wel
  • All

Many studies quantify the impacts of non-lethal human disturbance on animal behaviour to which animals respond by deploying what are interpreted as anti-predator strategies. These strategies are recognised as diverting time and energy from behaviours that would have occurred in the absence of human influences. In this report, levels of disturbance to grey seals are measured and these take into account the variety of seal vigilance levels as the prelude to / trigger of gross disturbance. Gross disturbance here denotes the stampeding of a seal or seals into the sea, where they were assembled on land, or where seals 'crash dive' when already in the sea.


The purposes of this data capture were to:

- Record the haul-out patterns of grey seals at Henllwyn Bay on Ynys Enlli/Bardsey when subject to no disturbance caused by people, in order to show examples of normal behaviour. To record examples of disturbance caused by human activity on land, in the sea and in boats, at Henllwyn for comparison with 'normal' / undisturbed behaviour. - Describe variables in seal behaviour observed over several tide cycles.

- Outline some aspects of survey design to best measure disturbance.

- Outline some site-specific management measures designed to reduce the frequency of disturbance events while also respecting the desires of people to have good views of and insights into the behaviour of grey seals at haul-out sites.

- Provide a short review of papers and reports on seal disturbance at haul-out sites on the shores of the northeast Atlantic. This will examine management measures that have been or are about to be deployed elsewhere and the ways that such measures are being, or will be, monitored.

Identification

Dynodydd
Identifier
NRW_DS110019
Laith Metadata
Metadata Language
English
Lineage

The natural pattern of grey seal emergence from and return to the sea at Henllwyn, Ynys Enlli/Bardsey was recorded at intervals of 15 minutes through the tide cycle, in order to understand 'natural' behaviour. Incidental notes were made describing seal behaviour and its apparent relationship to disturbance and relaxation. A count of seals in the sea adjacent to the haul-out sites was made at the same time. Simultaneously, instances of human activity at or near the site were recorded at the same interval. The time of arrival and the duration of time stayed at moorings in the bay by boats were recorded. Records were made of wind direction, wind speed and sea state, in order to discover to what extent they might influence site choice around the bay. At Henllwyn events from which gross disturbance resulted were recorded at the time they happened. Some of these events were filmed using a camcorder.
Dyddiad cyfeirnod y set ddata (Cyhoeddiad)
Dataset Reference Date (Publication)
2005-05-31

Temporal Extent

Begin date
2003-07-27
End date
2003-08-04
 
Categori pwnc
Topic category
  • Biota
    Biota
Perchennog
Owner
  Natural Resources Wales (NRW) -
Maes-y-Ffynnon, Penrhosgarnedd, Bangor, Gwynedd, LL57 2DW, Wales
http://naturalresources.wales/?lang=en
Cychwynnwr
Originator
  Westcott -
Nancherrow Cottage, Nancherrow, St Just-in-Penwith, Cornwall, TR19 7PW
<!__ Nowebsite __!>
 

Extent

Extent

Hyd
Geographic Extent
Caernarvonshire (49)
N
W
E
S
Map representing the geographic extent of the dataset


 

Vertical Extent

Medin Extent Keyword
littoral
 
 

Distribution

Fformat - Math a Disgrifiad
Format Type and Description
  • Documents ( )

    Specification

    Report with footage from Mini DV Video Cassette

 

Quality

Ansawdd Data
Data quality

Cwmpas Ansawdd
Quality Scope
Dataset
Dataset
Cydymffurfiad
Conformity
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
Explanation

This dataset has not been assessed for conformance to the referenced INSPIRE regulation.
Degree
false
Lineage

The natural pattern of grey seal emergence from and return to the sea at Henllwyn, Ynys Enlli/Bardsey was recorded at intervals of 15 minutes through the tide cycle, in order to understand 'natural' behaviour. Incidental notes were made describing seal behaviour and its apparent relationship to disturbance and relaxation. A count of seals in the sea adjacent to the haul-out sites was made at the same time. Simultaneously, instances of human activity at or near the site were recorded at the same interval. The time of arrival and the duration of time stayed at moorings in the bay by boats were recorded. Records were made of wind direction, wind speed and sea state, in order to discover to what extent they might influence site choice around the bay. At Henllwyn events from which gross disturbance resulted were recorded at the time they happened. Some of these events were filmed using a camcorder.
 

Keywords

Allweddair
Keywords

GEMET - INSPIRE themes, version 1.0
Math
Type
Theme
Theme

Dyfyniad
Citation

Dyddiad (Cyhoeddiad)
Date (Publication)
2008-06-01
Code
geonetwork.thesaurus.external.theme.httpinspireeceuropaeutheme-theme

Allweddair
Keywords

NRW Thesaurus
  • disturbance
  • grey seals
  • marine and freshwater inventory
  • halichoerus grypus
Math
Type
Theme
Theme

Dyfyniad
Citation

Dyddiad (Cyhoeddiad)
Date (Publication)
2026-08-27
Code
geonetwork.thesaurus.local.theme.converted_nrw-keywords

Allweddair
Keywords

SeaDataNet Parameter Discovery Vocabulary
Math
Type
Theme
Theme

Dyfyniad
Citation

Dyddiad (Cyhoeddiad)
Date (Publication)
2024-06-19
Code
geonetwork.thesaurus.external.theme.rdf+xml
 

Spatial Reference System

Code
Latitude and Longitude (EPSG::4326)
 

Content

Gwybodaeth Cynnwys
Content Information

Proffil CNC
NRW Profile

Elfennau CNC
Custom Elements

NRW Related Title

Field observations on the disturbance of grey seals in North Wales 2003
 

Constraints

Constraints

Limitations on Public Access and Use

Math o Gyfyngiad
Restriction type
Other restrictions
Other restrictions
 

Access Constraints Directive

Limitations
no limitations
 

Access Constraints Text

Other constraints

There are no access restrictions to this data. NRW may release, publish or disseminate it freely.
 

Use Constraints

Cyfyngiadau Defnyddio
Use constraints type
Other restrictions
Other restrictions
Other constraints

© 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

Metadata

Dynodydd Ffeil
File Identifier
4f4c4942-4343-5764-6473-313130303139 XML
Laith Metadata
Metadata Language
English
Math o adnodd
Resource type
Dataset
Dataset
Dyddiad Metadata
Metadata Date
2026-09-28T11:46:37.13Z
Enw Safonol Metadata
Metadata Standard Name
NRW
Fersiwn Metadata
Metadata Standard Version

1.0

Pwynt Cyswllt
pointOfContact
  Natural Resources Wales (NRW) -
Maes-y-Ffynnon, Penrhosgarnedd, Bangor, Gwynedd, LL57 2DW, Wales
http://naturalresources.wales/?lang=en
 
 

Publishing Body

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