I Grey Seal Distribution and Abundance in North Wales, 2002

Home , Caer Gybi (fort), East Mouse, Seiriol

Grey seal distribution and abundance in North Wales, 2002-2003

Westcott, S.M. & Stringell, T.B. Marine Monitoring Report No: 13

This is a report of research commissioned by the Countryside Council for Wales. The Council has a programme of research in scientific and other areas, which supports the development of policies and practical work and helps point the way to new countryside legislation. However, the views and recommendations presented in this report are not necessarily those of the Council and should, therefore, not be attributed to the Countryside Council for Wales. No part of this report may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without the prior permission of the Countryside Council for Wales.

i Report Number: 13

Publication Date: March 2004

Contract Number: FC-73-02-183

Nominated Officer: T.B. Stringell

Title: “Grey seal distribution and abundance in North Wales, 2002-2003”

Authors: Westcott, S.M. & Stringell, T.B.

Series editors: W.G. Sanderson (monitoring) A. McMath (marine mammals)

Restrictions: None

Distribution List

CCW:

T. Stringell CCW HQ x3 M. Baines x1 M.McMath, CCW HQ x1 S. Stansfield, Bardsey Island Bird B.Sanderson CCW HQ x1 Observatory x1 R. Holt, CCW HQ x1 A. Moralee, RSPB South Stack x1 L. Kay, CCW NWA x1 C. Sharpe, Manx Bird Atlas x1 Mike Camplin, CCW, H'FordW x1 T. Johnston, Exploris, Portaferry, NI x1 Blaise Bullimore, CCW H'fordW x1 C. Liret, Oceanopolis, Brest, Brittany x1 Paul Day, CCW NEA x1 R. Penrose, Marine Env Monitoring x1 Neil Smith, CCW NEA x1 Ivor Rees, Uni. Wales, Bangor x1 CCW HQ Library x1 Peter Hope Jones x1 CCW NWA Library x1 David Mawer, IoS Wildlife Trust x1 CCW Cardiff Library x1 T. Nicholson, Cornwall Wildlife Trust x1 CCW Mold Library x1 Marine Awareness North Wales x1 CCW West Area x1 Ian Bullock x1 CCW Skomer MNR x1 Jim Poole x1 Powell Strong x1 Others: David Thomas x1 JNCC Peterborough, Library x1 Chris Richardson, x1 EN Peterborough Library x1 Hilbre Island Observatory x1 R. Covey, EN Cornwall x1 K. Abt, Wadden Sea, Germany x1 SNH Edinburgh, Library x1 R. Witte, Texel, Netherlands x1 National Library Wales x1 UW Cardiff Library x1 National Assembly for Wales Library x1 UW Swansea Library x1 C. Duck, SMRU x1 UW Aberystwyth Library x1 Joe Breen EHS x1 UW Bangor Library x1 PML, Library, Plymouth x1 British Library, Document Supply Centre, S. Westcott x5 Boston Spa x1

Recommended citation for this volume:

Westcott, S & Stringell, T.B. 2004. Grey seal distribution and abundance in North Wales, 2002-2003. Bangor, CCW Marine Monitoring Report No: 13. 80pp.

ii PREFACE Under the Council Directive 92/43 EEC on the Conservation of natural habitats and of wild fauna and flora (the ‘Habitats Directive’), Member States are required to designate and conserve Special Areas of Conservation (SACs). The purpose of this is to maintain or restore habitats and species listed in Annex I and Annex II to ‘Favourable Conservation Status’. The grey seal Halichoerus grypus Fabricus, is a species listed in Annex II of the Habitats Directive and in Wales they are therefore ‘interest features’ of the Lleyn Peninsula and the Sarns, Pembrokeshire Marine, and Cardigan Bay candidate SACs.

The work presented in this report is the second study of its type to investigate the abundance of grey seals as a possible indicator of condition in the ‘Lleyn Peninsula and the Sarns’ SAC. Overall, the work has contributed to the development of methods and procedures for monitoring SACs as well as a dataset that will help to inform how targets could be set for the management of the SAC.

Over the last few years many other reviews, surveys, surveillance and monitoring projects have been initiated in Wales for Annex I and II habitats and species. Further CCW reports in this series will be produced as part of this ongoing programme to develop marine monitoring work that underpins the management of conservation sites.

RHAGAIR Dan Gyfarwyddeb y Cyngor 92/43 EEC ar warchod cynefinoedd naturiol a fflora a ffawna gwyllt (y ‘Gyfarwyddeb Cynefinoedd’), mae’n ofynnol i aelod-wladwriaethau ddynodi a gwarchod Ardaloedd Cadwraeth Arbennig (ACA). Diben hyn yw cynnal neu adfer cynefinoedd a rhywogaethau a restrir yn Atodiad I ac Atodiad II yr adran sy’n ymwneud ag elfennau sydd â statws cadwraethol ffafriol (‘Favourable Conservation Status’). Fe restrir y morlo llwyd Halichoerus grypus Fabricus yn Atodiad II y Gyfarwyddeb, ac yng Nghymru maent felly yn ‘nodweddion o ddiddordeb’ o fewn ymgeisydd am ACA Pen Llyn a’r Sarnau, ACA Morol Sir Benfro, o fewn ymgeisydd am ac o fewn ymgeisydd am ACA Bae Ceredigion.

Yr ail astudiaeth o’i bath gyda’r nod o archwilio faint o forloi llwyd a geir fel arwydd o gyflwr ACA Pen Llyn a’r Sarnau - dyma yw’r gwaith a gyflwynir yn yr adroddiad yma. Yn gyffredinol, mae’r gwaith wedi cyfrannu at ddatblygu dulliau a gweithdrefnau ar gyfer monitro ACA yn ogystal â set ddata a fydd yn ein cynorthwyo i weld sut y gellir gosod targedau yn ymwneud â rheoli ACA.

Yn ystod y blynyddoedd diwethaf, mae nifer o adolygiadau, arolygon, a phrosiectau goruchwylio a monitro eraill wedi cael eu rhoi ar y gweill yng Nghymru, sef rhai yn ymwneud â chynefinoedd a rhywogaethau Atodiad I ac Atodiad II. Felly, fe fydd adroddiadau pellach yn perthyn i’r gyfres hon yn cael eu llunio gan y Cyngor Cefn Gwlad yn seiliedig ar ganlyniadau’r rhaglen barhaus yma i ddatblygu gwaith monitro morol sy’n sail i ddulliau rheoli safleoedd cadwraethol.

1 SUMMARY The results of a full census of grey seal distribution and abundance for the period 29 July 2002 to 17 April 2003 are presented here. Occasional winter counts of seals on Ynys Enlli/Bardsey Island are also included. Where possible, female and well-marked male seals were photographed, in order to initiate a detailed study examining the fidelity of seals to North Wales assembly sites. However, in this survey the main purpose of site visits was to count the seals, as far as possible without disturbing them.

In North Wales, grey seal distribution at haul-out sites was almost entirely confined to three districts: 1) Ynys Enlli/Bardsey Island and Penrhyn Llyn/Lleyn Peninsula, 2) the West Hoyle Sandbank at the mouth of the Dee Estuary, adjacent to Hilbre Island, 3) a cluster of localities in Ynys Môn/Anglesey: Ynys Arw/North Stack, Ynysoedd y Moelrhoniaid/The Skerries, Trwyn y Gader/Carmel Head, Ynys Dulas and Ynys Seiriol/Puffin Island.

The sites used by grey seals in North Wales are usually remote from human access and adjacent to tide races; most consist of rocky island shores or sea cave sites. However, the site where the largest number of seals have been recorded, the West Hoyle Sandbank, is the one exception in that it consists exclusively of fine sand and offers immediate access to strongly tidal water.

As in 2001 (Westcott, 2002), counts were highest in summer at the north-east (West Hoyle Sandbank) and west (Ynys Enlli/Bardsey Island) extremes of the seals’ range in North Wales.

Highest winter counts were lower than highest summer counts for the region as a whole, and the apparent distribution of the seals also varied between summer and winter. Highest counts for single sites in winter were most often made in the central sector of their range, at the east Ynys Môn/Anglesey islands of Ynys Dulas and Ynys Seiriol/Puffin Island and in the far eastern sector, at West Hoyle Sandbank. Nevertheless, Ynys Enlli/Bardsey Island remained important at this time.

At all sites, counts made on consecutive days sometimes showed considerable fluctuation due to weather and sea conditions, or as an aftermath to human disturbance.

The number of seals using haul-out sites varied through the year, with the largest number and variety of sites being used during the peak weeks of the breeding season, in September and October.

2 CRYNODEB Yma, cyflwynir canlyniadau cyfrifiad llawn sydd wedi ceisio darganfod dosbarthiad a niferoedd morloi llwyd rhwng 29 Gorffennaf 2002 ac 17 Ebrill 2003. Hefyd, caiff y morloi a gafodd eu cyfrif o dro i dro ar Ynys Enlli yn ystod y gaeaf eu cynnwys. Fe orwedd yr arfordir a’r ynysoedd a arolygwyd rhwng Aberystwyth yn y de ac Aber Afon Dyfrdwy yn y gogledd-ddwyrain, gan gynnwys Ynys Môn.

Yng Ngogledd Cymru, roedd dosbarthiad morloi llwyd ar safleoedd a ddefnyddid fel safleoedd gorffwyso wedi eu cyfyngu bron yn gyfan gwbl i dair ardal: 1) Ynys Enlli a Phen Llyn, 2) Banc Tywod West Hoyle yng ngheg Aber Afon Dyfrdwy, ger Ynys Hilbre, 3) clwstwr o lecynnau yn Ynys Môn: Ynys Arw, Ynysoedd y Moelrhoniaid, Trwyn y Gader, Ynys Dulas ac Ynys Seiriol.

Fel arfer, mae’r ynysoedd a gaiff eu defnyddio gan forloi llwyd yng Ngogledd Cymru yn bell o fannau y gall y cyhoedd fynd arnynt, ac yn ymyl cerhyntau cryfion. Mae’r rhan fwyaf yn cynnwys glannau creigiog neu ogofâu môr. Fodd bynnag, y safle pwysicaf un, sef Banc Tywod West Hoyle, yw’r unig eithriad o ran ei fod yn cynnwys dim byd ond tywod mân, ac o ran y gellir mynd at ddwr llanwol cryf yn syth o’r safle.

Fel yn 2001 (Westcott, 2002), fe welwyd y rhan fwyaf yn ystod yr haf ym mhegynau gogledd-ddwyreiniol (Banc Tywod West Hoyle) a gorllewinol (Ynys Enlli) cwmpas y morloi yng Ngogledd Cymru.

Roedd y niferoedd mwyaf a gafodd eu cyfrif yn ystod y gaeaf yn llai na’r niferoedd mwyaf a gafodd eu cyfrif yn ystod yr haf wrth ystyried y rhanbarth yn ei gyfanrwydd, a hefyd fe welwyd gwahaniaeth yn nosbarthiad y morloi rhwng yr haf a’r gaeaf. Gan amlaf, mewn mannau tua chanol y rhanbarth y cafodd y nifer fwyaf o forloi eu cyfrif ar safleoedd unigol yn ystod y gaeaf, yn ynysoedd dwyreiniol Ynys Môn, sef Ynys Dulas ac Ynys Seiriol, ac ym mhen dwyreiniol pellaf y rhanbarth ym Manc Tywod West Hoyle. Er hynny, roedd Ynys Enlli yn dal i fod yn bwysig yn ystod y cyfnod yma.

Ym mhob safle, roedd y nifer a gafodd eu cyfrif ar ddyddiau dilynol weithiau yn amrywio’n sylweddol yn sgîl y tywydd â’r môr, neu o ganlyniad i’r ffaith fod pobl wedi tarfu arnynt.

Drwy gydol y flwyddyn, fe amrywiai’r niferoedd o forloi a ddefnyddiai safleoedd gorffwyso, gyda’r niferoedd a’r amrywiaeth mwyaf o safleoedd yn cael eu defnyddio yn ystod wythnosau prysuraf y tymor bridio, sef ym mis Medi a mis Hydref.

Pan oedd modd, fe dynnwyd lluniau o forloi benywaidd a morloi gwrywaidd amlwg, a hynny er mwyn rhoi astudiaeth fanwl ar y gweill i weld pa mor ffyddlon yw morloi i safleoedd ymgynnull yng Ngogledd Cymru. Dim ond trwy barhau â’r gwaith yma dros gyfnod o bum mlynedd o leiaf y gellir datblygu gwerth yr wybodaeth yma. Fodd bynnag, prif ddiben yr arfer o ymweld â safleoedd yn yr arolwg yma oedd cyfrif y morloi, gan darfu cyn lleied â phosibl arnynt.

3 Grey Seal Distribution and Abundance in North Wales, 2002-2003 Westcott, S.1 & Stringell, T.B.2

1 Nancherrow Cottage, Nancherrow, St Just-in-Penwith, Cornwall, TR19 7PW

2 Countryside Council for Wales HQ, Plas Penrhos, Ffordd Penrhos, Bangor, LL57 2LQ, UK

Contents

1 INTRODUCTION 6 1.1 Objectives...... 6

2 METHODS 8 2.1 Study area...... 8

2.2 Abundance and distribution data collection ...... 8

2.3 Seal assemblage composition ...... 10

2.4 Methods of site access ...... 10

2.5 Observatory observations ...... 11

2.6 Weather conditions and survey considerations ...... 13

2.7 Recording condition...... 13

2.8 Minimising disturbance...... 13

2.9 Data storage ...... 14

3 RESULTS 15 3.1 Overall seal distribution and abundance in North Wales, 2002-2003 ...... 15

Porth Bribys to Ynys Fydlyn ...... 15

Carreg Ddû ...... 15

Carreg y Trai (North) ...... 16

Carreg y Trai (South) ...... 17

Glanllynnau Skerries ...... 18

Gwylans Coast...... 18

Ynys Arw/North Stack Coast ...... 19

Porth Widlin Coast...... 20

Rhosgor...... 20

4 Trwyn Cilan...... 21

Trwyn y Gader/Carmel Head...... 22

Tudwals (composite) ...... 23

West Hoyle Sandbank (using standard methods)...... 23

Ynys Dulas ...... 24

Ynys Seiriol/Priestholm/Puffin Island ...... 25

Ynys Enlli/Bardsey Island (using standard methods)...... 25

Ynys Tudwal East ...... 26

Ynys Tudwal West...... 27

Ynysoedd y Moelrhoniaid/The Skerries ...... 28

Other sites...... 28

3.2 Winter seal counts at Ynys Enlli/Bardsey Island and West Hoyle Sandbank (using observatory observations)...... 29

3.3 Seal assemblage composition ...... 32

4 DISCUSSION 34 4.1 The distribution and abundance of grey seals at haul-out sites in North Wales ...... 34

4.2 Use of haul-out sites / seal assemblage composition...... 36

4.3 Recommendations ...... 37

5 ACKNOWLEDGEMENTS 39 6 REFERENCES 40 7 APPENDICES 41 Appendices 1-19 Seal counts made for each site visit. 41 Appendix 20 Site specific notes 65 Appendix 21 Risk Assessment 71 Appendix 22 Environmental influences on survey effort 75

5 1 INTRODUCTION

The UK population of grey seals represent about 40% of the world population and 95% of the EU population (SCOS, 2003). At the start of the 2000 breeding season, Great Britain held some 124,000 grey seals with a further 300-400 around the Isle of Man and Northern Ireland (SCOS 2000). The grey seal colonies of Wales represent over 2% of annual UK pup production (SCOS 2000).

A survey of grey seals in North Wales was conducted in 2001 for the Countryside Council for Wales (CCW). It provided baseline data on seal distribution at haul-out sites and on pup production (Westcott, 2002). In 2001, seals were found to be present at all surveyed sites throughout the year, albeit in varying numbers, with highest counts for a single site in summer being made at the West Hoyle Sandbank, Ynys Enlli/Bardsey Island and, to a lesser extent, at the Tudwal Islands (East and West). Highest winter counts were made at the two east Ynys Môn/Anglesey islands of Ynys Dulas and Ynys Seiriol/Puffin Island, with generally lesser but still substantial assemblies of seals counted at West Hoyle Sandbank and Ynys Enlli/Bardsey Island.

The most similar study to this survey was carried out in the Molène archipelago, off the west coast of Brittany, where the southernmost breeding sites of the grey seal in the east Atlantic, are found (Vincent, 2001). Boat-based censuses of haul-out assemblies were carried out once every two weeks from December 1997 to August 2000. A previous examination of grey seal distribution and abundance in North Wales (Swarbrick, 2000) proposed a summer population size of about 2000, a figure based mainly on a review of records held at Ynys Enlli/Bardsey Island Bird Observatory, Hilbre Bird Observatory and the Ynysoedd y Moelrhoniaid/Skerries Bird Observatory, but also on site visits for which no methodology is given.

Westcott (2002) tentatively estimated the total number of grey seals at North Wales sites as 365. This was calculated by multiplying the pup production estimate from the 2001 survey by a factor of 3.5 (one pup to three and a half adults) that was derived from a life table devised by Hewer (1974), in which it is assumed that the population is stable. The authors assert that applying a population number to the seals in North Wales should be viewed with caution.

During this survey, an east Atlantic phocine distemper epizootic progressed from the Danish island of Anholt, in May, around the North Sea basin and as far as the north Irish Sea coast. Although principally causing heavy mortality among common (harbour) seals, some grey seals also died on British coasts (SMRU, 2002). Concern that the phocine distemper virus might affect seals using the North Wales coast meant that close attention was given to the physical condition of the seals, with any abnormalities being noted.

Work on the current project began on 29 July 2002, although data from Hilbre Bird Observatory covers the period January to December 2002.

1.1 Objectives

Distribution and abundance

To record grey seal distribution and abundance on Pen Llyn/Lleyn Peninsula Ynys Enlli/Bardsey Island, Ynys Môn/Anglesey and the West Hoyle Sandbank in the Dee Estuary for the 2002-2003 season, while recognising that there is a conflict inherent in going on site to record numbers of seals and going on site to photograph individuals. At the same time, visits

6 to sites not previously identified as being used by seals were made, to check for any signs of expansion of known range.

A comparison is made of abundance and distribution data collected in North Wales in 2000- 2001 (Westcott, 2002) and data collected from the present survey.

The development of site based Standard Operating Procedures for future monitoring of distribution and abundance of grey seals in North Wales are reported separately (Westcott & Stringell, in prep).

Observatory/opportunistic data (seal numbers and calibration of methods)

Historically, data on grey seal numbers in North Wales have been collected by Hilbre Island Bird Observatory, RSPB (at Ynysoedd y Moelrhoniaid/The Skerries) and Ynys Enlli/Bardsey Island Bird Observatory (Westcott, 2002). In this survey, effort was made to report seal numbers and calibrate the different survey methods carried out by these organisations so that in future they will be comparable.

Guidelines for using observatory data in estimating seal numbers are reported separately as site based Standard Operating Procedures (Westcott & Stringell, in prep).

Photo-ID

The present work aimed to generate images for a site- and time-specific photographic identification catalogue for all seals photographed or filmed at nursery sites during the project. The work is reported in Westcott & Stringell (in prep). The catalogue will provide a basis for future work in the evaluation of breeding population size, the estimation of abundance using mark:recapture techniques, seal distribution, site fidelity and movement between sites.

The evaluation of methods for generating images for photographic identification of grey seals in North Wales is reported in Westcott & Stringell (in prep).

7 2 METHODS

2.1 Study area

The study area can be regarded as falling into three districts:

1. Penrhyn Llyn/Lleyn Peninsula, consisting mainly of sites on the south coast of the peninsula, west of Pwllheli, and Ynys Enlli/Bardsey Island

2. Ynys Môn/Anglesey: Ynysoedd y Moelrhoniaid/The Skerries, Ynys Cybi/Holy Island (consisting of sites between Ynys Lawd/South Stack and the harbour at Holyhead), Trwyn y Gader/Carmel Head (consisting of sites between Cemlyn Bay and Church Bay), and islands on the east coast, Ynys Dulas and Ynys Seiriol/Puffin Island.

3. West Hoyle Sandbank.

Ynysoedd y Moelrhoniaid/The Skerries Middle Mouse West Hoyle Sandbank East Mouse Trwyn y Gader/Carmel Head C Porth Bribys to Ynys Dulas Ynys Fydlyn B Ynys Arw/North Stack coast Ynys Seiriol/Puffin Ynys Island Llanddwyn Carreg Ddu Rhosgor Glanllynnau Skerries Porth Gwylan A Tudwals and Porth Widlin Carreg y Trai

Trwyn Cilan Ynys Enlli/Bardsey Sarn Badrig Island* Porth Meudwy Gwylans Coast

Map 1. Grey seal haul out sites in 2002-2003. The three districts are: (A) Pen Llyn/Lleyn Peninsula including Ynys Enlli/Bardsey Island, (B) Ynys Môn/Anglesey, and (C) West Hoyle Sandbank. * For an enlargement of Bardsey Island see Map 2.

2.2 Abundance and distribution data collection

A haul-out site denotes a place ashore where seals are found. Consequently, nursery sites are also classified as haul-out sites in the context of the distribution and abundance survey.

8 As previously described (Westcott, 2002; Bardsey Island Bird Observatory Annual Report, 2002; Westcott & Stringell, 2003), maximum counts were usually made within an hour of low tide at all sites. However, during RIB-based survey effort, to cover the maximum number of sites, a reasonable approximation of (maximum) seal numbers can be made in the period two hours either side of low tide. Vincent (2001) took censuses from two hours before low tide to low tide, this being regarded as the period when the number of seals resting ashore or in the waters adjacent to the haul-out site were at the maximum and fairly stable (Y. Roger, unpublished data quoted in Vincent, 2001). In the event of a new site being discovered, the way to confirm the point in the tide cycle at which seal assembly size settles at its maximum is to run an activity budget on the pattern of emergence from the sea, noting seal numbers at intervals of 10 or 15 minutes (Westcott, 2002).

All sites described in Westcott (2002) were visited again through the 2002-2003 survey. Every actual and potential seal haul-out site was visited as many times as possible from the end of July 2002 to April 2003. For the greater part of the year, unless environmental factors made access impossible, all sites were visited between two and five times per month. However, Glanllynnau Skerries was visited only at monthly intervals because of its relative lack of use by seals. Most sites were visited between 17 and 25 times during the survey. However, 32 counts made at Ynys Enlli/Bardsey Island resulted from a mixture of opportunistic visits and one extended stay on the island. Data collected by personnel from the Hilbre Bird Observatory did not employ the current survey’s standard methods, ie counts were made opportunistically (see section 2.5). Consequently, counts resulting from the observatory methods are reported separately (in section 3.2) from data collected using standard survey methods carried out by the author (in section 3.1).

At each site the number of seals was counted, differentiating between those on land and those in the sea adjacent to the site. Counts were never estimated. All counts represent tallies of individual seals. At nearly all sites, binoculars (Leica, 10x50) were used, whenever necessary, during counts. On site, information was recorded in a waterproof notebook at the time the observation was made. Weather and sea conditions were recorded at each site visit (see section 2.6). Data collected in the field were entered into a custom-made Microsoft AccessTM grey seal database on the same day that observations were recorded (see section 2.9).

In the rare instance when a stampede occurred as a result of the activity of the researcher, seals were counted in blocks of ten. Apart from the ethical imperative to try to avoid causing disturbance to the seals, an on-site count should always be more accurate than a count of seals in the sea.

Special considerations for surveying West Hoyle Sandbank

Due to the exceptional difficulty in approaching seals assembled at the West Hoyle Sandbank on the Dee Estuary, all counts except one were made from Hilbre Island, from a high vantage point near the Bird Observatory using a Leica APO Televid telescope with a 20-60x zoom. Because it was not possible to differentiate accurately between the sexes at that range, a simple total count of seals assembled is made. The same methods are used by Observatory staff in making seal counts.

On one occasion, landfall was made at a distance of about 300 metres from the seals and a hide was used to conceal the approach of observers to a distance of about 100 metres. From this distance, using the telescope and a digital camera, images of the assembly was captured and a count was made upon return to base, enlarging the image on to a television screen.

9 2.3 Seal assemblage composition

Each count was broken down to record the number of individual males, females, juveniles, pups and those which could not be identified with confidence.

In the field, differentiation was instinctive, based on 15 years experience. To test that others with similar experience were making similar identification of the sex and age of animals, the author has periodically tested his own discrimination skills with those of Cecile Vincent (University of La Rochelle); close agreement was found in all seal categories.

In general, there is considerable sexual dimorphism. Males are larger and heavier than females, the males having notably heavier necks often clearly covered with rolls of fat. Males tend to be fairly monotonous in colour all over (usually slightly paler on the ventral surface), although when wet a pattern of blotches often becomes visible.

Females, when wet, are often silvery-grey on the dorsal surface and white or cream (sometimes tinged a tin (rusty) colour) on the throat and the ventral surface. This area is also clearly patterned with blotches. Indeed, each seal has a pattern of blotches unique to itself, which may be regarded as the grey seal equivalent to a human fingerprint.

‘Juveniles’ here signify those seals which have not yet attained sexual maturity (which varies in onset between 3 and 6 years (Anderson, 1990)). In fact, it is impossible to be certain of the age of such a seal just by looking at it. Therefore, the counts included in this report identify the smallest seals in any assembly away from nursery areas as juveniles. In the case of many small females, their pelage appears no different to that of a mature female (except in being smaller). Males and some females, when dry, have a pelage that appears sandy or honey- coloured.

Pups have white coats (that may be stained with yellow or orange while in utero and remain that colour until up to the third day of life) until the first moult, which may occur before weaning. Non-weaned moulted pups are more plump than juveniles, as are recently weaned pups (under normal circumstances).

Unidentified seals were those which could not be ascribed a sex with sufficient confidence. In the field, this usually resulted when passing at distance in a boat bound for another location

2.4 Methods of site access

As in the 2001 survey (Westcott, 2002), this survey was mainly seaborne, during which a wave ski was used to transport the fieldworker and survey equipment to and from sites that were mainly inaccessible from land. With the North Wales pupping sites being confined mainly to relatively short stretches of coastline, and with sea conditions being mainly benign through the survey periods, it was not necessary to use a boat to reach sites. Investigating sites using a wave ski was quicker than swimming to and from sites and allowed near-silent approach to be made to each site, thus keeping the disturbance to mother and pup to a minimum.

Two sites had to be visited by means of a hired boat (Ynys Enlli/Bardsey Island and Ynysoedd y Moelrhoniaid/The Skerries). Sites at Trwyn y Gader/Carmel Head, Carreg Ddu, Rhosgor and Glanllynnau Skerries were visited on foot.

At some sites approached from the sea, no landing was made (e.g. Ynys Tudwal West, Ynys Tudwal East, Carreg y Trai North, Carreg y Trai South, Ynys Gwylan-fawr and Ynys

10 Gwylan-bach) because it was easier to make the counts from the sea. At these sites, an initial count was made from a distance exceeding 100 metres in order to avoid causing disturbance to the seals. Nearly always, this would suffice. However, in cases where there was any doubt as to numbers, then a very close approach was made, which always resulted in the seals stampeding into the sea.

At Rhosgor, Carreg Ddu, Trwyn y Gader/Carmel Head, counts were made from overlooking vantage points.

Where landings had to be made, an initial scan was made during the approach to the site to identify where seals were assembled and, equally important, where they were absent. This, along with prevailing sea conditions and the availability of suitable landing places, determined where landfall should be made. It was imperative that the researcher was out of the line of sight and the array of other keen seal senses, such as hearing and smell. There had to be a secure place where the wave ski could be safely left, taking account of the potential rise of any incoming tide. There had to be a secluded route that the observer could take in order to arrive, undetected, at a vantage point from where seals could be located and counted. Movement on site is complicated by the tendency of the seals to gather in a number of separate assemblies on the heavily used sites (e.g. Ynys Seiriol/Puffin Island and Ynys Dulas).

Procedures outlined in Westcott & Stringell (in prep) describe how seals can remain largely undisturbed during on site fieldwork.

2.5 Observatory observations

Ynys Enlli/Bardsey Island Observatory

In order that observatory data would be comparable with counts made in this survey, staff at Ynys Enlli/Bardsey Island Bird Observatory made changes to their normal counting procedures and made seal counts at, or within an hour of, low tide.

From 26 December 2001, winter counts on Ynys Enlli/Bardsey Island, made by Dave and Libby Barnden, were the result of a walk around the south end of the island, from Porth Solfach south to Maen-du and north to Cafn Enlli (Map 2). All individuals seen hauled out were counted, but sex and age were not recorded because they could not be confidently verified.

11 Map 2 Ynys Enlli/Bardsey Island survey sites where observatory staff collected data.

Hilbre Island Bird Observatory

In 2002, Observatory personnel made 107 daily counts from Hilbre Island Bird Observatory. Although counts from the observatory did not use comparable methods to the current survey (i.e. around the hour of low tide), they remained consistent with the manner in which they

12 have been collected during the past 40 years (Williams, pers. comm. 2003). Observatory data are included in this report because they contribute to a perception of the unique importance of this site throughout the year.

2.6 Weather conditions and survey considerations

The influence of wind direction and speed, sea state, wave action upon sites and day length affected the ability to survey seal sites. The limited availability of boat transport to Ynys Enlli/Bardsey Island and Ynysoedd y Moelrhoniaid/The Skerries also inhibited the survey on some occasions.

During ‘windows’ in bad weather, intense effort was made to visit the maximum number of sites each day. In exceptional cases, this might result in up to five sites being visited.

There is a huge variation in tide times between the seal sites around the region (Lavers, 2001, 2002, 2003). At high water, the average tidal differences when applied to high water time at Liverpool (Alfred) show Hilbre Island at minus 13 minutes, east Ynys Môn/Anglesey sites at approximately minus 30 minutes, Carreg Ddu at minus 2 hours, Ynys Enlli/Bardsey Island at minus 3 hours 18 minutes and St.Tudwal’s Road at minus 3 hours 17 minutes. This huge variation, particularly in summer, when daylight hours are so much longer, allowed low tide site visits to be made for at least two districts each day. For example, the Gwylans Coast could be visited in the morning followed by Ynys Dulas in the afternoon, or the Dee Estuary in the morning and the Tudwals in the afternoon.

More than any other single factor, sea state determined when site visits could be made and, in particular, the size of waves breaking on the shores. At all sites, winds blowing at Beaufort Wind Scale Forces 0-3 presented no difficulties in accessing sites. In winds blowing at forces 4 and 5, some sites could still be accessed safely, albeit with a greater measure of difficulty. At these times, landings remained possible on lee shores. At Beaufort Wind Scale Force 6 and above, health and safety requirements kept observers ashore. However, for sites under high cliffs on lee shores, access remained a possibility on foot.

Reduced daylight length between November and February, along with generally rougher sea conditions, periodically limited opportunities for making visits to the most exposed sites.

2.7 Recording condition

While this survey was taking place, a phocine distemper epizootic progressed from the Danish island of Anholt, in May, around the North Sea basin and as far as the north Irish Sea coast. (SMRU, 2002). Concern that it may affect seals using the North Wales coast meant that close attention was given to the physical condition of the seals. Any abnormal conditions (in particular, signs of discharges and lesions, or of unnatural lethargy) were noted.

2.8 Minimising disturbance

At the outset, the decision was taken to avoid causing disturbance to seals, as far as field craft and good fortune permitted, both in this and any other survey. The decision was an ethical one, connected to the context of this survey, which was to provide data helpful in informing management decisions designed to maintain a favourable conservation status for the seals in

13 marine special areas of conservation in North Wales. On site, effort was always made to remain unseen and unheard by the seals.

However, where fieldworkers disturbed seals, data (in the form of counts and identification photographs) were collected before the fieldworker departed the site. At such times, as at all other times, effort was made to remain on site for the minimum amount of time required to secure the data, and to continue to behave as quietly as possible.

It is worth noting that counts made of seals on shore are likely to be more accurate than counts of seals in the sea, where seals may be constantly surfacing and slipping below the surface.

At all times, sites were approached as discreetly as possible in order to avoid alerting seals to the approach of fieldworkers and to avoid drawing the attention of members of the public to the seals.

2.9 Data storage

An MS Access™ database was set up to record information about seals at every site where they occur. A full data archive description is given by Westcott & Stringell (in prep.). The database includes:

• A site reference number, Ordnance Survey co-ordinates, orientation, ease of access, a description of the site including the nature of access, the shape of the entrance, type(s) of substrata, potentially perilous, hazardous or otherwise unexpected features of the site as well as a scanned plan view if it is a sea cave site.

• The nearest launching points for both a canoe or wave ski and for a RIB are identified.

• Human use of the land and sea in the vicinity of the site.

• An indication of levels of disturbance at the time of every visit.

• Any seals present at or just offshore from the site are recorded as ‘male, female, juvenile, pup or unidentified’. There is a section for notes in which detail of adult and juvenile seals can be recorded along with any other details of interest regarding the visit. This might include information about identification marks borne by seals or reference to identification photographs or film taken.

In addition, images of individual seals captured on transparencies and negatives were catalogued and stored electronically at CCW Bangor. Images were coded, identifying location, date, sex, left/right/head-on profiles as well as the number of images known to be held of the same seal. Where the individual is known to be the mother of a pup or is known to be the locally dominant male, this is included in the code (Westcott & Stringell, in prep). The transparencies and photographs are also held at CCW Bangor.

14 3 RESULTS

3.1 Overall seal distribution and abundance in North Wales, 2002-2003

All fieldwork took place between the end of July 2002 and April 2003, so these results will fail to identify any sites where seal numbers peak in the early summer (see Westcott, 2002).

Seals were assembled in all-age groups of varying size at North Wales' haul-out sites through the survey period. In most assemblies at most sites, females outnumbered males (see section 3.3).

Largest summer counts were recorded for West Hoyle Sandbank on the Dee Estuary (330 on 11 July 2003) and Ynys Enlli/Bardsey Island (228 on 30 July 2003).

However, opportunistic counts made from Hilbre Island Bird Observatory include 11 counts that exceed this number, with a highest count of 518 on 11 May 2002.

Most of the largest winter counts were recorded for the east Ynys Môn/Anglesey islands: Ynys Dulas (139 on 5 February 2003) and Ynys Seiriol/Puffin Island (127 on 16 December 2003) and for the West Hoyle Sandbank (116 on 26 November 2002). However, (opportunistic) counts made from Hilbre Island Bird Observatory include a record of 210 for 23 November 2002, as well as 6 other counts that exceeded 100. Large counts were also recorded for Ynys Enlli/Bardsey Island (up to 107 on the 25 November, 2002).

Smaller but regionally significant assemblies of seals were counted at the Tudwals (up to 66 on the 7 August 2002), the Gwylans Coast from Carreg Chwislen to the Gwylans (up to 42 on 17 December 2002) and Ynysoedd y Moelrhoniaid/The Skerries (up to 49 on 27 March 2003).

The number of seals assembled ashore is generally greater in the summer months than in winter for the North Wales region as a whole. However, seals use the islands off the east coast of Ynys Môn/Anglesey much more intensively in the winter months than in summer. In contrast, use of the West Hoyle Sandbank and Ynys Enlli/Bardsey Island rises to a peak in the summer months.

The following site data indicates the abundance of the seals at each site in the North Wales region. Where pups were found, they were included in the count and are recorded on the graphs. Each date entry on the graphs indicates independent visits to the site. Full datasets for every site regularly surveyed are presented in Appendices 1 to 19a.

Porth Bribys to Ynys Fydlyn

No seals were seen here during the observation period.

Carreg Ddû

Pups were not born here. This site was used exclusively as a resting place, but use of the site by seals appears sporadic. During visits made in this survey, seals were more often absent than present, nearly always in low numbers. The highest count of 22 was made on 30 July

15 2002, but only on two other occasions did numbers exceed 5. Females usually outnumbered males.

UID 15 juvenile female 10

no. of seals male

30.07.0209.08.0223.08.0231.08.0204.09.0219.09.0225.09.0202.10.0209.10.0231.10.0214.11.0222.11.0202.12.0218.12.0201.02.0314.02.0318.02.0304.03.0325.03.0312.04.0316.04.0322.04.03

Figure 1 Grey seal abundance at Carreg Ddû, based on 21 site visits

Carreg y Trai (North)

Pups were not born here. Carreg y Trai (North) was used exclusively as a resting place.

Little used during the winter months, highest counts for this site are usually recorded in the summer months although during this survey the highest count of 35 seals was recorded on the 15 April 2003. In all counts, female seals outnumber males.

Direct comparison with counts made in 2001 are not possible as a composite count was made including seals from Carreg y Trai North and South. However, numbers were higher in 2001.

On many of the summer visits, a number of boats were close to this site and people were watching the seals. Disturbance of seals was observed but not quantified on some of these occasions.

16 40 35 30 25 UID juvenile 20 female 15

no. of seals male 10 5 0

04.08.0207.08.0218.08.0219.08.0202.09.0209.09.0217.09.0203.10.0210.10.0217.11.0205.12.0217.12.0231.01.0304.02.0312.02.0316.02.0315.03.0319.03.0326.03.0304.04.0315.04.03

Figure 2 Grey seal abundance at Carreg y Trai (North), based on 21 site visits

Carreg y Trai (South)

Pups were not born here. It was used exclusively as a resting place.

Like its neighbour, this islet was little used in the winter months. In this survey, highest counts were recorded in late summer and early autumn, with the highest count of 32 seals being made on 17 September 2002.

Direct comparison with counts made in 2001 are not possible as a composite count was made including seals from Carreg y Trai (North) and (South). However, numbers were higher in 2001. Females always outnumbered males.

On many of the summer visits, a number of boats were close to this site and people were watching the seals. Disturbance of seals was observed but not quantified on some of these occasions.

17 35

25 UID 20 juvenile 15 female

no. of seals male 10

04.08.0207.08.0218.08.0219.08.0202.09.0209.09.0217.09.0203.10.0210.10.0217.11.0205.12.0217.12.0231.01.0304.02.0312.02.0316.02.0315.03.0319.03.0326.03.0304.04.0315.04.03

Figure 3 Grey seal abundance at Carreg y Trai (South) based on 21 site visits

Glanllynnau Skerries

No seals were seen here during the observation period.

Gwylans Coast

In the years 2001-2003, this was the most important seal pupping locality in the North Wales region (Westcott & Stringell, 2003). A feature of site use here is that most are used exclusively as nursery sites (for giving birth and the rearing of the pups to independence). However, three sea cave sites (Ogof Lwyd West, Ogof Lwyd East and Ogof Morlo) and both the Gwylan islands are used through the year and in the winter months; rarely, there were large assemblies of up to 21 seals.

Seals were always present, in numbers between 2 and 42.

On some summer visits, boats were close to this site and people were watching the seals. Such events resulted in disturbance of seals into the sea on every occasion. These observations are qualitative.

18 45 40 35 pups 30 UID 25 juvenile 20 female

no. of seals 15 male 10 5 0

29.07.0204.08.0215.08.0222.08.0201.09.0205.09.0208.09.0216.09.0223.09.0229.09.0204.10.0213.10.0231.10.0216.11.0224.11.0205.12.0217.12.0231.01.0311.02.0315.02.0316.03.0325.03.0328.03.0303.04.0313.04.03

Figure 4 Grey seal abundance along the Gwylans Coast, based on 25 site visits.

Ynys Arw/North Stack Coast

In 2002, this coast was found to be the second most important pupping locality in the North Wales region (Westcott & Stringell, 2003). As on the Gwylans Coast, most seal sites in this district are used only during the breeding season. However, Ogof Arw and Ogof Morlo were found to be used through the year.

In the current survey, the maximum count was made in September. Numbers were highest between September and March, usually exceeding 10. Seals were nearly always present in numbers that ranged between 6 and 37.

40 35 30 pups 25 UID 20 juvenile 15 female no. of seals male 10 5 0

16.08.0228.08.0206.09.0212.09.0221.09.0228.09.0206.10.0217.10.0230.10.0215.11.0206.12.0211.02.0317.02.0319.02.0315.03.0323.03.0327.03.0305.04.0315.04.03

Figure 5 Grey seal abundance along the Ynys Arw/North Stack Coast, based on 16 site visits.

19 Porth Widlin Coast

Only occasionally and very lightly used by seals. Local fishermen speak of it having been used as a breeding location in the 1990s, although this was not confirmed by the recent surveys (Westcott, 2002; Westcott & Stringell, 2003). Seals were often present in low numbers, counts showing between 1 and 4 (the maximum count was recorded on 2 October), mainly on rocks to seaward of Porth Widlin. Regular counts were not made in 2001, so comparisons cannot be made.

Seals were more likely to be seen at these sites in summer than in winter months.

UID 3 juvenile female 2

no. of seals male

02.08.0208.08.0227.08.0207.09.0219.09.0202.10.0209.10.0230.10.0214.11.0222.11.0207.12.0202.02.0319.02.0312.04.03

Figure 6 Grey seal abundance along the Porth Widlin Coast (Porth Widlin to Traeth Penllech), based on 14 site visits.

Rhosgor

Rhosgor was used by seals through the year but was used most heavily during the late summer and autumn. Counts showed assembly size varied between 1 and 30. Females always outnumbered males, while there was sometimes a large contingent of juveniles. According to the farmer below whose land the seals assemble, seal numbers seem not to have changed noticeably over the last 20 years (Williams, pers. obs. 2003).

People walking on the beach here were observed disturbing the seals only when they approached them over the rocks.

20 35

25 UID 20 juvenile 15 female

no. of seals male 10

30.07.0205.08.0209.08.0217.08.0227.08.0204.09.0214.09.0226.09.0226.09.0208.10.0212.10.0214.10.0201.11.0202.11.0222.11.0202.12.0218.12.0201.02.0314.02.0318.02.0304.03.0326.03.0327.03.0312.04.0316.04.03

Figure 7 Grey seal abundance at Rhosgor, based on 25 site visits. Two records are shown for 26.09.02, one visit being made in the morning and the second visit being made in the evening of that day.

Trwyn Cilan

As elsewhere (e.g. the Gwylans Coast and the Ynys Arw/North Stack Coast), more sites are used in the breeding season than at any other time of year. This is a regionally important site for pup production, but unimportant to seals during the remainder of the year (Westcott & Stringell, 2003).

In the current survey, two important new sites were identified, so a full comparison cannot be made with seal counts for 2001.

In 2002, a maximum count of 18 was made in September. Highest counts were made in September and October, with the four observations that exceeded 5 seals being made during the period of pup production.

21 20 18 16 14 pups 12 UID 10 juvenile 8 female no. of seals 6 male 4 2 0

22.08.0201.09.0209.09.0217.09.0223.09.0224.09.0206.10.0211.10.0231.10.0216.11.0206.12.0217.12.0220.02.0316.03.0326.03.0328.03.0305.04.03

Figure 8 Grey seal abundance at Trwyn Cilan, based on 17 site visits.

Trwyn y Gader/Carmel Head

Pups are born here, but outside of the breeding season, seals occur only occasionally. In 2002 the maximum count of 3 was in September.

Pup production dropped from 9 in 2001 to 3 in 2002, perhaps due to the fly tipping on to the main nursery beaches. No other comparison can be made because the sites were not visited regularly in 2001. In 2002, a maximum seal count of 3 was made

Some disturbance was noted but not quantified during the 2001 season of pup production, when people came down to nursery beaches and closely approached pups there. Disturbance caused by people occurred in 2002 not only from the fly-tipping but also from Coastguard activity.

4 pups 3 UID juvenile 2 female no. of seals male 1

30.07.0206.08.0219.08.0231.08.0206.09.0213.09.0220.09.0227.09.0207.10.0213.10.0227.10.0203.11.0218.11.0203.12.0213.02.0316.02.0323.03.0317.04.03

Figure 9 Grey seal abundance at Trwyn y Gader/Carmel Head, based on 17 site visits.

22 Tudwals (composite)

The Tudwals (consisting of four sites – see Appendices 3-7) comprise the third most important summer haul-out site for seals in the North Wales region (after the West Hoyle Sandbank and Ynys Enlli/Bardsey Island).

A very small number of pups are born on the two main islands, but not on Carreg y Trai North and South, both islets being tidal. The islands and islets are used almost exclusively as a resting place where females always heavily outnumber males and juveniles. In this survey, highest counts were made in the summer and autumn, numbering between 12 and 67.

On many of the summer visits, a number of boats were close to this site and people were watching the seals. Disturbance of seals was observed but not quantified on some of these occasions.

50 pups 40 UID juvenile 30 female no. of seals 20 male

04.08.0207.08.0218.08.0219.08.0202.09.0209.09.0217.09.0203.10.0210.10.0217.11.0205.12.0217.12.0231.01.0304.02.0312.02.0316.02.0315.03.0319.03.0326.03.0304.04.0315.04.0323.04.03

Figure 10 Grey seal abundance at the Tudwals, based on 21 site visits.

West Hoyle Sandbank (using standard methods)

The West Hoyle Sandbank is the most important seal haul-out site in Wales. It is also exceptional in being the only sandbank haul-out site in the region. The seals always haul-out in the same place on the sandbank, adjacent to water that is approximately 20 metres deep.

There is no record of pups ever having been born here, although a dead pup was found near Red Rocks on Hilbre Island in 2002.

Staff at the Hilbre Bird Observatory report that disturbance takes place only occasionally, during the summer months, usually only when people land on the sandbank.

23 250

200

150 UID Seals 100 no. of seals

11.09.0230.09.0226.11.0220.12.0221.12.0222.12.0222.01.0323.01.0324.01.0327.01.0328.01.0329.01.0330.01.0310.02.0322.02.0323.02.0319.03.03

Figure 11 Grey seal abundance at the West Hoyle Sandbank, Dee Estuary, based on 17 site visits using standard methods. UID = unidentified in terms of sex and age group.

Ynys Dulas

Used by only small numbers of seals in the summer, with Ynys Seiriol/Puffin Island (below) it becomes the most important winter assembly district for the North Wales region, with Ynys Dulas almost always the more important of the two (see Appendices 16 and 17).

Seal counts during this survey varied between 5 and 139 with the highest counts recorded between November and April. Common seals are usually present; between 1 and 4 have been recorded.

People occasionally land on the island from canoes or small motor boats. This was seen to cause disturbance to seals.

160 140 120 100 UID juvenile 80 female 60

no. of seals male 40 20 0

02.08.0203.08.0202.09.0212.09.0220.09.0203.10.0210.10.0205.11.0213.11.0216.12.0213.01.0305.02.0313.02.0315.02.0317.03.0325.03.0303.04.0317.04.0322.04.03

Figure 12 Grey seal abundance at Ynys Dulas, based on 19 site visits.

24 Ynys Seiriol/Priestholm/Puffin Island

Used by only small numbers of seals in the summer, with Ynys Dulas (above) it becomes the most important winter assembly district for the North Wales region.

Seal counts during this survey varied between 11 and 130. It is an unusual site in that males usually outnumber females and there is usually a substantial representation by juvenile seals through the year.

Common seals sometimes occur here, although never more than 1 was seen on any site visit.

Subsequent to the end of fieldwork in this survey, a seal pup was born at the north-west tip of the island. This was the first birth recorded here since North Wales seal survey work began in January 2001. Therefore, it appears that seal pups are born here in some years but not in others.

People, including marine tourism operators from Beaumaris, come in boats to watch the seals here. This does not appear to disturb them. However, any landing close to where the seals assembled disturbed them.

140

120

100 UID 80 juvenile 60 female

no. of seals male 40

01.08.0218.08.0228.08.0202.09.0214.09.0222.09.0207.10.0210.10.0213.11.0203.12.0216.12.0231.01.0304.02.0312.02.0318.03.0326.03.0304.04.0316.04.03

Figure 13 Grey seal abundance at Ynys Seiriol/Puffin Island, based on 18 site visits.

Ynys Enlli/Bardsey Island (using standard methods)

Ynys Enlli/Bardsey Island is the second most important seal site, year-round, after West Hoyle sandbank, in terms of the number of individuals assembling there

On the main island, nearly all seals use haul-out sites south of Cafn, from Henllwyn to Maen- du at the south tip of the Island. On the west coast, the main haul-out sites are usually around Porth Solfach. West of Porth Solfach, there is a smaller island, Carreg yr Honwy. This is important to seals when sea conditions permit.

25 Highest counts for Ynys Enlli/Bardsey Island sites are usually recorded in the summer months with lowest counts between September and November, when the pups are being born. During this survey, a maximum count of 228 was recorded on 30 July 2003. A minimum count of 20 was made on 25 September 2002.

Disturbance occurs here and it was studied by Goodchild (2003) and Westcott & Stringell (in prep.).

250

200 pups 150 UID juvenile 100 female no. of seals male 50

08.08.0222.08.0224.08.0226.08.0229.08.0202.09.0204.09.0206.09.0208.09.0225.09.0212.10.0211.11.0226 1111.12.02 0226.12.0206.01.0326.07.0328.07.0330.07.0301.08.0302.08.0303.08.0304.08.03

Figure 14 Grey seal abundance at Ynys Enlli, based on 46 site visits.

Ynys Tudwal East

One or two pups are usually born here each year. Otherwise, this is predominantly a resting place where females always heavily outnumber males.

Seals almost completely abandon island haul-out sites in the summer months. Counts varied between 0 and 54 (on 3 October, 2002). Seals are mainly confined to the east, south-east and south-west shores of Ynys Tudwal (East).

On many of the summer visits, a number of boats were close to this site and people were watching the seals. Disturbance of seals was observed but not quantified on some of these occasions.

26 60

50 pups 40 UID 30 juvenile female

no. of seals 20 male 10

04.08.0207.08.0218.08.0219.08.0202.09.0209.09.0217.09.0203.10.0210.10.0217.11.0205.12.0217.12.0231.01.0304.02.0312.02.0316.02.0315.03.0319.03.0326.03.0304.04.0315.04.03

Figure 15 Grey seal abundance at YnysTudwal (East), based on 21 site visits.

Ynys Tudwal West

One or 2 pups are usually born here each year. Otherwise, this is predominantly a resting place.

Seals almost completely abandon island haul-out sites in the summer months. Counts varied between 1 and 35 (on 26 March, 2003). Females always outnumbered males. Seals are mainly confined to the east, south-east and south-west shores.

On many of the summer visits, a number of boats were close to this site and people were watching the seals. Disturbance of seals was observed but not quantified on some of these occasions.

40 35 30 pups 25 UID 20 juvenile 15 female no. of seals male 10 5 0

04.08.0207.08.0218.08.0219.08.0202.09.0209.09.0217.09.0203.10.0210.10.0217.11.0205.12.0217.12.0231.01.0304.02.0312.02.0316.02.0315.03.0319.03.0326.03.0304.04.0315.04.03

Figure 16 Grey seal abundance at Ynys Tudwal West, based on 21 site visits.

27 Ynysoedd y Moelrhoniaid/The Skerries

Past records suggest that largest seal assemblies occur in the summer months (Westcott, 2002), but that peak was not apparent from data collected in this survey, when highest counts were recorded in late winter and spring. However, attempts to visit the island were greatly frustrated by sea conditions and by the availability of boats to ferry researchers across the difficult seaway. Counts varied between 24 and 49. Females usually outnumber males at this site and there is usually a substantial representation by juvenile seals through the year.

In the summer of 2003, counts were made by RSPB wardens following the same methods as were deployed in this survey. Unfortunately, results arrived too late for inclusion in this report. However, these would have shown the largest assemblies of the year for that site.

Boats make use of the sheltered waters in the lagoon below the lighthouse. On some occasions, this disturbs seals hauled out on rocks around the lagoon, usually causing them to move to other rocks or to remain in the sea at the north end of the island.

50 pups 40 UID 30 juvenile female

no. of seals 20 male 10

16.08.02 15.09.02 27.09.02 05.11.02 15.11.02 11.02.03 21.02.03 27.03.03 06.04.03

Figure 17 Grey seal abundance at Ynysoedd y Moelrhoniaid/The Skerries, based on 9 site visits.

Other sites

A small number of seals have been seen using Ynysoedd Gwylanod, islets surrounded by very strong tidal currents off the south coast of Ynys Cybi/Holy Island. Seals have been seen occasionally using outlying rocks at Carreg y Trai near Aberffraw and at Ynys Llanddwyn, off the south-west tip of Ynys Môn/Anglesey. However, regular visits were not made to these sites because of time constraints.

28 3.2 Winter seal counts at Ynys Enlli/Bardsey Island and West Hoyle Sandbank (using observatory observations)

Ynys Enlli/Bardsey Island

Figures 19 to 22 shows seal counts of winter assemblies at Ynys Enlli/Bardsey Island sites collected by Dave and Libby Barnden (island tenants) from December 2001 to January 2003. The sites on Ynys Enlli are: Porth Solfach, Porth Hadog, Maen-du, Maen-du South-east to Lighthouse Cove (east), First Cove South and Henllwyn,

During the summer months, Henllwyn, is usually the main haul-out site for seals on the main island. In the winter, both Henllwyn and First Cove South, which is, in effect, a continuation of Henllwyn southward, function also as nurseries for seal pups.

Lighthouse Cove East is used as a seal pup nursery. Seal pups are also born at Maen-du (SE), particularly at Ogof Diban. The seals, however, rarely use Porth Hadog, only one seal pup was found here on 25 January 2002. Seals also use the rocks and islets at the southern extremity of Solfach cove. One seal was found at Porth Solfach on 08 February 2002.

120

100

no. of seals 60

26.12.0102.01.0209.01.0216.01.0225.01.0230.01.0208.02.0221.02.0211.11.0226.11.0205.12.0211.12.0218.12.0226.12.0201.01.0306.01.0307.01.03

Figure 18 Grey seal abundance at Henllwyn, based on 17 site visits.

29 120

100

no. of seals 60

26.12.0102.01.0209.01.0216.01.0225.01.0230.01.0208.02.0221.02.0211.11.0226.11.0205.12.0211.12.0218.12.0226.12.0201.01.0306.01.0307.01.03

Figure 19 Grey seal abundance at ‘First Cove South’, based on 17 site visits.

20 18 16 14 12 no. of seals 10 8 6 4 2 0

26.12.0102.01.0209.01.0216.01.0225.01.0230.01.0208.02.0221.02.0211.11.0226.11.0205.12.0211.12.0218.12.0226.12.0201.01.0306.01.0307.01.03

Figure 20 Grey seal abundance at Lighthouse Cove (east) to Maen-du South-east (south-east coast), based on 17 site visits.

30 18 16 14 12 10 no. of seals 8 6 4 2 0

26.12.0102.01.0209.01.0216.01.0225.01.0230.01.0208.02.0221.02.0211.11.0226.11.0205.12.0211.12.0218.12.0226.12.0201.01.0306.01.0307.01.03

Figure 21 Grey seal abundance at Maen-du, based on 17 site visits.

Figure 22 illustrates the total number of seals observed on Ynys Enlli/Bardsey Island by the island tenants on 17 independent field visits.

160 140 120 Solfach 100 Porth Hadog Maen du 80 To Maen du (SE) 60

no. of seals First Cove South 40 Henllwyn 20 0

26.12.0102.01.0209.01.0216.01.0225.01.0230.01.0208.02.0221.02.0211.11.0226.11.0205.12.0211.12.0218.12.0226.12.0201.01.0306.01.0307.01.03

Figure 22 Seal counts of winter assemblies using Ynys Enlli/Bardsey Island sites: Porth Solfach, Porth Hadog, Maen-du, Maen-du South-east to Lighthouse Cove (east), First Cove South and Henllwyn, December 2001 to January 2003.

31 West Hoyle Sandbank

Although the data collected by observatory personnel cannot be compared with counts made elsewhere through the region, due to the way in which the data is collected, they do show the year-round importance of the site, including 7 observations that exceed 400 seals.

Seal numbers varied between 1 and 518. Highest counts were recorded in late spring and summer. Lowest counts were recorded during late autumn and winter, although even in winter, one count of 210 was made.

600

500

400

300

no.of seals 200

100

0 03/01/02 03/02/02 03/03/02 03/04/02 03/05/02 03/06/02 03/07/02 03/08/02 03/09/02 03/10/02 03/11/02 03/12/02

Figure 23 Grey seal abundance at the West Hoyle Sandbank, Dee Estuary, based on 107 visits, not using standard methods.

3.3 Seal assemblage composition

At all sites, except Ynys Seiriol/Puffin Island, over the period of one year, females outnumber males: at 10 of the 16 sites, females comprised more than half of all seals counted (Table 1). However, examination of the detail of every count (see Appendices 1-19) shows that during certain periods of the year, at a minority of sites, males outnumber females or else have approximate equivalence of numbers (Ynys Dulas and Ynys Enlli/Bardsey).

The high incidence of unidentified seals at Ynys Enlli/Bardsey is partly the result of non- differentiated counts made by Dave and Libby Barnden and by Neil Goodchild (Goodchild, 2003). The remainder of the counts reflect the fact that nearly all counts of seals on Carreg yr Honwy (the rocky island to the west of Ynys Enlli/Bardsey) were made from the main island, from which distance differentiation could not be achieved with confidence.

The counts made of seals using the West Hoyle Sandbank, being made by telescope from Hilbre Island, always represent a simple aggregate count. Differentiation between the sexes could not be reliably achieved from that distance.

32 Table 1. Breakdown of sex and age of total number seals counted at haul-out sites in North Wales, with the percentage expressed in the brackets (rounded up or down to nearest full percentage). UID = unidentified. Numbers expressed do not indicate the number of individuals but the summed frequency of each count during the entire survey period. Detail can be found in Appendices 1-19. Site f-male f-female f-juvenile f-pups f-UID Total

Carreg Ddû 9 (16%) 44 (80%) 2 (4%) 0 0 55

Carreg y Trai (N) 8 (7%) 105 (86%) 9 (7%) 0 0 122

Carreg y Trai (S) 10 (8%) 104 (78%) 19 (14%) 0 0 133

Ynys Tudwal (E) 20 (12%) 148 (75%) 20 (12%) 2 (1%) 0 190

Ynys Tudwal (W) 19 (9%) 184 (84%) 13 (5%) 4 (2%) 0 220

Tudwals: a composite 57 (9%) 541 (81%) 61 (9%) 6 (1%) 0 665

Gwylans Coast 48 (17%) 149 (54%) 11 (4%) 61 (22%) 9 (3%) 278

Ynys Arw (North 68 (28%) 104 (43%) 6 (3%) 63 (26%) 0 241 Stack) Coast

Porth.Widlin-Traeth 1 (7%) 11 (86%) 1 (7%) 0 0 13 Penllech

Rhosgor 29 (15%) 148 (76%) 18 (9%) 0 0 194

Trwyn Cilan 16 (19%) 38 (45%) 2 (2%) 29 (34%) 0 85

Trwyn y Gader 2 (23%) 3 (33%) 0 4 (44%) 0 9 (Carmel Head)

Ynys Dulas 533 (38%) 684 (49%) 142 (10%) 0 36 (3%) 1395

Ynys Seiriol (Puffin 511 (52%) 294 (30%) 175 (18%) 0 0 980 Island)

Ynysoedd y 93 (27%) 195 (56%) 36 (10%) 23 (7%) 0 347 Moelrhoniaid (Skerries)

Ynys Enlli (Bardsey 1416 1765 535 (10%) 24 (0%) 1452 5192 Island) (28%) (33%) (29%)

33 4 DISCUSSION

4.1 The distribution and abundance of grey seals at haul-out sites in North Wales

The validity of Swarbrick’s North Wales summer population estimate of c.2000 (Swarbrick, 2000) is questionable because estimating a summer population number based only on the number of seals hauling out does not take into account the seals present in the water. Satellite tracking studies (McConnell et al, 1992) showed that seals spent more time in the sea than on land and only hauled out when in the vicinity of a haul-out sites for between 15 and 37% of time available, while the remainder of the time was spent in the sea in the vicinity of the sites. The data presented in the present study therefore represents a more accurate indication of the number of seals.

However care needs to be taken in interpreting the present data. It is not always possible to be sure whether human disturbance has occurred at some time prior to a count being made. Consequently, when unexpectedly low counts were recorded, they might have been the result of human disturbance. If so, an unwittingly false impression of numbers of seals making use of the site on that day will have been recorded. This occurs because often, once disturbed, grey seals using these sites do not haul out again on that particular tide. An obvious candidate for a count made following disturbance occurred on 15 August 2002 for the West Hoyle Sandbank (Appendix 15a). Just one seal was recorded as present during a month when assembly size tended to be high or very high (120-454 seals, excluding the example quoted).

A 2001-2002 ‘population’ estimate of c.365 was made by Westcott (2002), based on the number of pups born at North Wales sites multiplied by a correction factor of 3.5 derived from a life table devised by Hewer (1964), in which it is assumed that the population is stable. Similarly, based on the same assumptions a 2002-2003 ‘population’ estimate can be given as c.385 based on 110 pups recorded by Westcott & Stringell (2003). This method for calculating seal numbers has been in use for several decades (e.g. Baines et al, 1995). However, the total number of grey seals present at North Wales haul-out sites at all times clearly greatly exceeded this figure (Westcott, 2002). This appears to suggest either that:

• the correction factor used to arrive at the population figure is erroneous. This may be the case in assessing ‘population size’ along a coast where seal numbers are localised and where assemblies exceed 50 at only a small number of sites

• or else there is always a high representation of seals in North Wales from other colonies around the Irish Sea and perhaps beyond.

Either way Hewer’s method clearly does not relate to the numbers of seals being recorded in the N. Wales region through the present study year. Little is known of grey seal foraging areas in North Wales, their range and how much movement of individuals into and out of the North Wales sites is occurring. It would be more correct to say that at present we lack sufficient data to make a regional population estimate, especially when the term ‘population’ is not precisely defined geographically.

In a study of grey seal movements at sea, it was generalised that seals spend a high percentage of time at or near haul-out sites, take short trips to local offshore foraging areas and conduct benthic dives, and can travel large distances (McConnell et al, 1999). Such distances in this study referred to movements between the Farnes, Abertay, the Orkneys, the Shetlands, the Faroes and beyond.

34 Much remains to be discovered about the movements of grey seals in and beyond the Irish Sea, and what constitutes a geographical ‘population’. Vincent (2001) reports on the movements of four rehabilitated and six wild young grey seals that were fitted with satellite tags and released in Brittany in 1997 and 1999. Haul-out sites used by these seals include north and west Brittany sites as well as sites in the Channel Isles, Cornwall, the Isles of Scilly, Skomer, the Saltee Islands and Dublin Bay. The tracking of seals at sea did not form part of this survey, but the results of the Brittany trials give a first accurate insight into the movements of seals at sea in this region.

West Hoyle sandbank

The importance of West Hoyle sandbank in the Dee Estuary as a haul out site was first noted by Craggs & Ellison (1960), who offer a maxima of 117 for February (1951-57), and later described by Hewer (1974), who states ”numbers can exceed 200 animals in the summer”. Based on these literature, Anderson (1977) noted a trend of increasing size of seal assemblies hauled out on the West Hoyle Sandbank, had continued. Westcott (2002) agreed that the trend of increasing assembly size has apparently continued, and based this observation on maximum counts made by Hilbre Bird Observatory in 1964 (146), 1974 (145), 1984 (178), 1994 (470) and 2002 (518). However, it should be noted that there has been no consistency in the timing of the counts made by members of the Hilbre Bird Observatory in relation to the height of the tide. Therefore, the results of more than 40 years of seal counts should be viewed with caution, although clearly a great increase has taken place. Future assessment of the number of seals should be based on exclusively low tide (plus or minus an hour) counts.

Swarbrick (2000) uses updated versions of the same data described above and drew conclusions based on maximum counts, which are likely to be anomalous, as shown in Westcott (2002). Then, for example, the maximum 2001 West Hoyle Sandbank count (547) exceeded the second highest count by about 70, with assembly size sometimes varying quite markedly from day-to-day. The same was true in 2002, when the highest count of 518 exceeded the second highest count by 61 (in both years, these counts were made using the non-standard methods). There were also sometimes marked variations between counts made on subsequent days at Ynys Enlli/Bardsey Island, where the standard methods were deployed.

The principal question arising from the present survey is ‘how representative are the counts of actual seal numbers at any one time?’ The variation in (sometimes) daily counts being made at West Hoyle Sandbank (albeit being made opportunistically rather than in compliance with methods used elsewhere in the present survey) is striking. Overall, assessment of numbers clearly needs to be conducted at a state of the tide and season when temporal variability is at a minimum.

Ynys Enlli/Bardsey Island

On Ynys Enlli/Bardsey Island an apparent increase in assembly size has also been noted (Hope Jones & Meredydd, 1994). This is based on count data made when time was available rather than over the low tide period, and which is therefore likely to be less accurate than the methods described throughout the rest of the present study. Furthermore, counts for Carreg yr Honwy, where made at all, are likely to have been less accurate when made from Ynys Enlli/Bardsey Island, as proven in this survey. Accurate counts for that site can be made only by landing there or from a boat.

35 4.2 Use of haul-out sites / seal assemblage composition

The general trends of site use were largely as described for 2001 (Westcott, 2002). In winter, the most important sites were Ynys Dulas, Ynys Seiriol/Puffin Island, the West Hoyle Sandbank and Ynys Enlli/Bardsey Island. In summer, the most important sites were the West Hoyle Sandbank, Ynys Enlli/Bardsey Island, the Tudwals and Ynysoedd y Moelrhoniaid/The Skerries.

A feature of the counts made by Vincent (2001) was the limited variation in numbers assembled (c.30-60). Highest counts were made in February and March; the lowest counts were made in October and November (the breeding season). The low numbers in the breeding season is another area of similarity with this survey, at least at island sites such as Ynys Enlli/Bardsey Island and Ynysoedd y Moelrhoniaid. In crude terms, it can be said that numbers of seals using North Wales haul-out sites in summer considerably exceeds numbers using the same sites in winter except at Ynys Dulas and Ynys Seiriol/Puffin Island, where the reverse holds true: these two sites draw the largest winter (November to March) concentrations of seals in the region, with the exception of the West Hoyle Sandbank, where occasional very high counts are made at this time. It is possible that Ynys Dulas and Ynys Seiriol/Puffin Island offer haul-outs that are refuges from the prevailing winter winds and storms.

As in the current survey, Vincent (2001) categorised seals into age (adult, immature and yearling) and sex classes. However in the current survey, differentiation between immature and yearling was not made. Indeed, the dividing line between the categories ‘juvenile’ and (young) ‘adult’ in this survey was sometimes uncertain, as it must have been in Vincent (2001), where differentiation between ‘yearling’ and ‘immature’ would also have been uncertain in many (especially female) cases. At such times, categorisation is instinctive, and although this may appear subjective and unrepeatable methodology, Vincent and Westcott met in 2000 to share impressions of the sex/age category of a number of photographs of seals. At that time, the workers were in total agreement about every individual identified. Vincent (2001) noted marked seasonal differences in the use of the area were noted for males and females at Molène. This was not so strongly apparent in this survey.

The crude seal assemblage data (Table 1) does not show fluctuations in seal numbers by sex and age through the year for sites. The omission of any kind of breakdown by sex or age for West Hoyle Sandbank indicates the need for focussing detailed attention there, especially as it holds the largest annual aggregate number of seals for any North Wales site.

The results of this survey suggest that North Wales is an important area for female grey seals. Examination of the site visit data contained in the appendices (1-19a) confirms that N. Wales remains of value to females the year round. The Tudwals area was, for the most part, almost exclusively used by females while at Rhosgor, on the north coast of Penrhyn Llyn, females comprised 75% of all seals counted.

In general, males rarely comprise more than 25% of any assembly. They were recorded in highest numbers and percentages at island sites: Ynys Seiriol/Puffin Island, Ynys Dulas, Ynysoedd y Moelrhoniaid/The Skerries and Ynys Enlli/Bardsey. Again, the importance or otherwise of West Hoyle Sandbank from this point of view was not established.

Table 1 indicates that juveniles are nowhere a major component of the seal assemblies of North Wales, although 18% of seals counted at Ynys Seiriol/Puffin Island were so categorised (they occurred in similar numbers at Ynys Dulas). Highest numbers (but not percentages) of juveniles were recorded in the assemblies using Ynys Enlli/Bardsey.

36 At 4 sites (Gwylans Coast, Ynys Arw/North Stack Coast, Trwyn y Gader/Carmel Head and Trwyn Cilan) pups form a high percentage of the total number of seals counted through the year. Clearly, this signifies sites heavily used during the breeding season but little outside that time.

The use of seal tracking telemetry and the use of photo-identification are means that would serve to associate individual seals with a variety of sites over a period of time. Presently, we have a record of site use that does not clearly inform us of how the seals are using the site. To date, we can say that seals use them and we can offer maximum-minimum variations in numbers using them. For these figures to become more meaningful for the management of the site, it is important to identify the nature/pattern of site(s) use by following the movements of a sample of identified seals.

4.3 Recommendations

The ideal for examining seal abundance at any site is to make accurate daily counts over a long period of time. To some extent, this was achieved for Ynys Enlli/Bardsey Island over a 10-day period in 2003, but was otherwise a weakness inherent in the sampling method used here. In future, it is worth considering a dual approach to monitoring/making counts: (1) sampling the majority of sites as described in the methods of this report ie c.3 counts per month, and (2) daily counts at selected sites, e.g. Ynys Ennlli/Bardsey Island, West Hoyle Sandbank, Tudwals, and in winter Ynys Dulas and Ynys Seiriol. This dual approach would be useful for examining the overall abundance of seals whilst calibrating for apparent effects of disturbance, wind direction, and sea state that would require more detailed recording of seal numbers and site use. In future survey work, it would make sense to commission more accurate daily low tide counts of seals for the most important sites from people resident at those sites. The utility of these data would be enhanced if methods were standardised using the approached described in the present work.

Daily low tide counts might be conducted by the Hilbre Island Bird Observatory, although other methods (use of hides or an anchored boat) should also be considered in order to learn about the sex ratio and to identify these seals as individuals using tracking telemetry.

For the West Hoyle Sandbank, there are regionally unique challenges, both with regards to making counts and learning more about where these seals spend the remainder of their time. This is an unusual site in several ways, most especially in its relative isolation from any other seal site.

Sites known to be subject to human pressure that would benefit from a more regular count effort include the Tudwals (in the summer), Ynys Dulas, Ynys Seiriol/Puffin Island and Ynysoedd y Moelrhoniaid. Here, attention should be given to any apparent influence of human activity on haul-out behaviour.

Care must be taken during future surveys to minimise researcher disturbance where possible.

Trwyn y Gader/Carmel Head sites should be closely monitored for fly-tipping and disturbance in future and their apparent influence on seal haul-out behaviour.

Seal movements at sea between and beyond the North Wales sites need to be understood if abundance figures are to be interpreted for management. Satellite tracking, mobile phone tagging, hat-tagging and photo-identification offer an array of potential means.

37 Any future survey of the grey seals of ‘North Wales’ or of ‘Wales’ should incorporate or link to the Isle of Man seals, especially to the Calf of Man, which is closer to the seal sites of North Ynys Môn/Anglesey than are those sites to either the West Hoyle Sandbank or the south coast of Penrhyn Llyn/Lleyn Peninsula.

38 5 ACKNOWLEDGEMENTS

Thanks to CCW for funding and therefore making possible this work, and especially to Mandy McMath for having faith in and inspiring me.

Especial thanks to Tom Stringell for tormenting this final report from me. Unexpectedly, I have appreciated this belated education.

For help in the field, which was the best part of this adventure, thank you to Neil Goodchild, Tom Stringell, George Stoyle, Richard Shucksmith and Rohan Holt.

Thank you to Dave & Libby Barnden for their help on Ynys Enlli, to Alastair Moralee and the wardens for their help on Ynysoedd y Moelrhoniaid and to Hilbre Bird Observatory, especially Steve Williams, for supplying the 2002 seal count data for the West Hoyle Sandbank.

39 6 REFERENCES

Anderson, S.S. 1977. The grey seal in Wales. Nature in Wales 15 (3): pp.114-123 Bardsey Island Bird Observatory Annual Reports, 1988-2002 Craggs, J.D. & Ellison, N.F. 1960. Observations on the seals of the (Welsh) Dee Estuary. Proc.Zool.Soc.Lond. 138: pp.375-385. Goodchild, 2003. The effect of human disturbance on the haul-out behaviour of grey seals (Halichoerus grypus). BSc. Thesis, Bangor University Library. 37pp. Hewer, H.R., 1974. British seals. The New Naturalist, 57. Collins. 256pp.. Hilbre Bird Observatory Annual Reports, 1954-2001. Hope Jones, P. & Meredydd, H. 1994. Trends in numbers of grey seals at Bardsey Island. Bardsey Island Observatory Report 38: pp.74-79. Lavers. 2001-2003. Liverpool & Irish Sea Tide Table, 2001-2003. 10pp. McConnell, B.J., Chambers, C., Nicholas, K.S. & Fedak, M.A. 1992. Satellite tracking of grey seals (Halichoerus grypus). J.Zool., Lond. 226: pp.271-282. McConnell, B.J., Fedak, M.A., Lovell, P. & Hammond, P.S. 1999. Movements and foraging areas of grey seals in the North Sea. J.Appl.Ecol. 36: pp.573-590. SCOS, 2000. Scientific Advice on Matters Related to the Management of Seal Populations: 2002. SCOS 02/2, pp57. [http://www.smru.st-and.ac.uk/CurrentResearch.htm/scos.htm]. SCOS, 2003. Scientific Advice on Matters Related to the Management of Seal Populations: 2003. pp58. [http://www.smru.st-and.ac.uk/CurrentResearch.htm/scos.htm]. SMRU. (2002) Sea Mammal Research Unit Phocine Distemper Virus Status Reports, Nos.1- 19. Swarbrick, M.L. 2000. Distribution of the grey seal (Halichoerus grypus) in North Wales, and the effects of environmental conditions on haul-out behaviour. 3rd.Year Honours Project as partial fulfilment of degree requirements for BSc Honours Marine Biology/Zoology. 50pp. Vincent, C. 2001. Bases ecologiques de la conservation du phoque gris, Halichoerus grypus, en mer d’Iroise. These de Doctorat d’Universite de Bretagne Occidentale. Soutenue le 11.07.2001. Westcott, S.M. 2002. The distribution of Grey Seals (Halichoerus grypus) and census of pup production in North Wales, 2001. CCW Contract Science Report No.499: 140pp. Westcott, S & Stringell, T.B. 2003. Grey Seal Pup Production For North Wales, 2002. Bangor, CCW Marine Monitoring Report No: 5a. 57pp. Westcott, S.M and Stringell, T.B. (in prep). Grey Seal Photo-identification in North Wales, 2003 Westcott, S.M. and Stringell, T.B. (in prep.). Disturbance of grey seals, 2003. Westcott, S.M. and Stringell, T.B. (in prep.). Towards procedural guidelines for studying grey seals in North Wales, 2004.

40 7 APPENDICES

Appendices 1-19 Seal counts made for each site visit.

Appendices 1-19a record seal counts made for every site visit during the survey. These include counts made by Hilbre Island Bird Observatory staff for the West Hoyle Sandbank (Appendix 15a) and winter counts made on Ynys Enlli (Bardsey Island) by Dave & Libby Barnden (Appendix 19a).

Appendix 1 Grey seal abundance at Porth Bribys to Ynys Fydlyn (Ynys Môn) Date f-male f-female f-juvenile f-pups f-UID Total

31 August 2002 0 0 0 0 0 0

06 September 2002 0 0 0 0 0 0

13 September 2002 0 0 0 0 0 0

20 September 2002 0 0 0 0 0 0

13 October 2002 0 0 0 0 0 0

03 November 2002 0 0 0 0 0 0

18 November 2002 0 0 0 0 0 0

03 December 2002 0 0 0 0 0 0

13 February 2003 0 0 0 0 0 0

16 February 2003 0 0 0 0 0 0

41 Appendix 2 Grey seal abundance at Carreg Ddû Date f-male f-female f-juvenile f-pups f-UID Total

30 July 2002 5 17 0 0 0 22

09 August 2002 0 0 0 0 0 0

23 August 2002 0 3 0 0 0 3

31 August 2002 0 0 0 0 0 0

04 September 2002 0 1 1 0 0 2

19 September 2002 0 0 0 0 0 0

25 September 2002 0 0 0 0 0 0

02 October 2002 0 0 0 0 0 0

09 October 2002 0 0 0 0 0 0

31 October 2002 2 4 0 0 0 6

14 November 2002 0 4 0 0 0 4

22 November 2002 0 1 0 0 0 1

02 December 2002 0 0 0 0 0 0

18 December 2002 2 8 0 0 0 10

01 February 2003 0 2 0 0 0 2

14 February 2003 0 0 0 0 0 0

18 February 2003 0 0 0 0 0 0

04 March 2003 0 0 0 0 0 0

25 March 2003 0 0 0 0 0 0

12 April 2003 0 4 1 0 0 5

16 April 2003 0 0 0 0 0 0

42 Appendix 3 Grey seal abundance at Carreg y Trai (North) Date f-male f-female f-juvenile f-pups f-UID Total

04 August 2002 1 13 0 0 0 14

07 August 2002 1 14 3 0 0 18

18 August 2002 0 0 0 0 0 0

19 August 2002 0 0 0 0 0 0

02 September 2002 1 11 1 0 0 13

09 September 2002 1 17 0 0 0 18

17 September 2002 0 2 1 0 0 3

03 October 2002 0 0 0 0 0 0

10 October 2002 1 8 1 0 0 10

17 November 2002 0 0 0 0 0 0

05 December 2002 0 1 0 0 0 1

17 December 2002 0 0 0 0 0 0

31 January 2003 0 1 1 0 0 2

04 February 2003 0 0 0 0 0 0

12 February 2003 0 0 0 0 0 0

16 February 2003 0 0 0 0 0 0

15 March 2003 0 0 0 0 0 0

19 March 2003 0 0 0 0 0 0

26 March 2003 0 3 0 0 0 3

04 April 2003 0 5 0 0 0 5

15 April 2003 3 30 2 0 0 35

43 Appendix 4 Grey seal abundance at Carreg y Trai (South) Date f-male f-female f-juvenile f-pups f-UID Total

04 August 2002 3 14 4 0 0 21

07 August 2002 3 13 4 0 0 20

18 August 2002 0 0 0 0 0 0

19 August 2002 0 0 0 0 0 0

02 September 2002 0 15 3 0 0 18

09 September 2002 0 3 1 0 0 4

17 September 2002 1 28 3 0 0 32

03 October 2002 0 0 0 0 0 0

10 October 2002 3 25 3 0 0 31

17 November 2002 0 0 0 0 0 0

05 December 2002 0 0 0 0 0 0

17 December 2002 0 2 0 0 0 2

31 January 2003 0 2 0 0 0 2

04 February 2003 0 0 0 0 0 0

12 February 2003 0 0 0 0 0 0

16 February 2003 0 0 0 0 0 0

15 March 2003 0 1 0 0 0 1

19 March 2003 0 0 0 0 0 0

26 March 2003 0 0 0 0 0 0

04 April 2003 0 1 1 0 0 2

15 April 2003 0 0 0 0 0 0

44 Appendix 5 Grey seal abundance at Ynys Tudwal (East) Date f-male f-female f-juvenile f-pups f-UID Total

04 August 2002 0 0 0 0 0 0

07 August 2002 0 0 0 0 0 0

18 August 2002 0 1 0 0 0 1

19 August 2002 0 0 0 0 0 0

02 September 2002 0 0 0 0 0 0

09 September 2002 1 0 0 0 0 1

17 September 2002 1 2 0 0 0 3

03 October 2002 4 45 5 0 0 54

10 October 2002 0 0 0 0 0 0

17 November 2002 2 11 0 1 0 14

05 December 2002 1 11 4 1 0 17

17 December 2002 2 12 5 0 0 19

31 January 2003 1 12 1 0 0 14

04 February 2003 1 12 2 0 0 15

12 February 2003 1 8 1 0 0 10

16 February 2003 1 12 0 0 0 13

15 March 2003 1 8 1 0 0 10

19 March 2003 2 11 0 0 0 13

26 March 2003 1 0 0 0 0 1

04 April 2003 1 3 1 0 0 5

15 April 2003 0 0 0 0 0 0

45 Appendix 6 Grey seal abundance at Ynys Tudwal (West) Date f-male f-female f-juvenile f-pups f- Total UID

04 August 2002 2 15 1 0 0 18

07 August 2002 2 24 2 0 0 28

18 August 2002 1 9 0 1 0 11

19 August 2002 1 23 0 1 0 25

02 September 2002 1 0 1 0 0 2

09 September 2002 1 6 1 0 0 8

17 September 2002 1 4 1 0 0 6

03 October 2002 0 0 0 1 0 1

10 October 2002 1 9 0 1 0 11

17 November 2002 1 13 1 0 0 15

05 December 2002 0 1 2 0 0 3

17 December 2002 4 13 0 0 0 17

31 January 2003 0 2 1 0 0 3

04 February 2003 0 2 0 0 0 2

12 February 2003 0 4 1 0 0 5

16 February 2003 0 4 0 0 0 4

15 March 2003 0 1 1 0 0 2

19 March 2003 0 0 0 0 0 0

26 March 2003 3 32 0 0 0 35

04 April 2003 1 22 1 0 0 24

15 April 2003 0 0 0 0 0 0

46 Appendix 7 Grey seal abundance at Tudwals: a composite Date f-male f-female f-juvenile f-pups f-UID Total

04 August 2002 6 42 5 0 0 53

07 August 2002 6 51 9 0 0 66

18 August 2002 1 10 0 1 0 12

19 August 2002 1 23 0 1 0 25

02 September 2002 2 26 5 0 0 33

09 September 2002 3 26 2 0 0 31

17 September 2002 3 36 5 0 0 44

03 October 2002 4 45 5 1 0 55

10 October 2002 5 42 4 1 0 52

17 November 2002 3 24 1 1 0 29

05 December 2002 1 13 6 1 0 21

17 December 2002 6 27 5 0 0 38

31 January 2003 1 17 3 0 0 21

04 February 2003 1 14 2 0 0 17

12 February 2003 1 12 2 0 0 15

16 February 2003 1 16 0 0 0 17

15 March 2003 1 10 2 0 0 13

19 March 2003 2 11 0 0 0 13

26 March 2003 4 35 0 0 0 39

04 April 2003 2 31 3 0 0 36

15 April 2003 3 32 2 0 0 37

47 Appendix 8 Grey seal abundance at Gwylans coast: Pen y Cil to Trwyn Talfarach Date f-male f-female f-juvenile f-UID f-pups Total

29 July 2002 1 1 0 0 0 2

04 August 2002 0 0 0 3 0 3

15 August 2002 2 3 0 0 0 5

22 August 2002 1 14 1 1 0 17

01 September 2002 2 6 0 0 1 9

05 September 2002 1 7 0 0 3 11

08 September 2002 3 10 0 0 4 17

16 September 2002 5 16 2 2 8 33

23 September 2002 6 11 0 0 11 28

29 September 2002 4 14 0 0 12 30

04 October 2002 2 12 0 0 10 24

13 October 2002 5 11 0 0 9 25

31 October 2002 2 4 1 0 1 8

16 November 2002 0 4 0 2 1 7

24 November 2002 2 5 1 0 1 9

05 December 2002 2 3 2 1 0 8

17 December 2002 10 28 4 0 0 42

48 Appendix 9 Grey seal abundance at Ynys Arw (North Stack) Coast: Porth Namarch to Ogof Gogarth Date f-male f-female f-juvenile f-pups f-UID Total

16 August 2002 0 0 0 0 0 0

28 August 2002 0 0 0 0 0 0

06 September 2002 0 0 0 0 0 0

12 September 2002 2 2 0 2 0 6

21 September 2002 1 3 0 3 0 7

28 September 2002 5 21 0 11 0 37

06 October 2002 5 13 0 12 0 30

17 October 2002 5 13 0 16 0 34

30 October 2002 2 10 0 14 0 26

15 November 2002 3 2 0 5 0 10

06 December 2002 5 12 3 0 0 20

11 February 2003 11 3 1 0 0 15

17 February 2003 7 1 0 0 0 8

19 February 2003 7 3 0 0 0 10

15 March 2003 4 7 0 0 0 11

23 March 2003 3 4 0 0 0 7

27 March 2003 3 4 1 0 0 8

05 April 2003 3 3 0 0 0 6

15 April 2003 2 3 1 0 0 6

49 Appendix 10 Grey seal abundance at Porth Cadlan to Trwyn Talfarach Date Total

09 August 2002 0

23 August 2002 0

25 August 2002 0

04 September 2002 0

16 September 2002 0

03 October 2002 0

14 October 2002 0

27 October 2002 0

19 November 2002 0

04 December 2002 0

19 December 2002 0

16 March 2003 0

30 March 2003 0

05 April 2003 0

16 April 2003 0

50 Appendix 11 Grey seal abundance at Porth Widlin to Traeth Penllech Date f-male f-female f-juvenile f-pups f-UID Total

02 August 2002 0 1 0 0 0 1

08 August 2002 0 2 0 0 0 2

27 August 2002 0 0 0 0 0 0

07 September 2002 0 0 0 0 0 0

19 September 2002 0 1 0 0 0 1

02 October 2002 1 3 0 0 0 4

09 October 2002 0 1 0 0 0 1

30 October 2002 0 2 0 0 0 2

14 November 2002 0 1 0 0 0 1

22 November 2002 0 0 1 0 0 1

07 December 2002 0 0 0 0 0 0

02 February 2003 0 0 0 0 0 0

19 February 2003 0 0 0 0 0 0

12 April 2003 0 0 0 0 0 0

51 Appendix 12 Grey seal abundance at Rhosgor Date f-male f-female f-juvenile f-pups f-UID Total

30 July 2002 1 1 0 0 0 2

05 August 2002 1 10 1 0 0 12

09 August 2002 0 0 0 0 0 0

17 August 2002 1 2 0 0 0 3

27 August 2002 3 5 1 0 0 9

04 September 2002 1 7 0 0 0 8

14 September 2002 1 3 0 0 0 4

26 September 2002 (am) 1 6 2 0 0 9

26 September 2002 (pm) 1 6 1 0 0 8

08 October 2002 2 11 0 0 0 13

12 October 2002 1 25 4 0 0 30

14 October 2002 2 11 2 0 0 15

01 November 2002 0 8 1 0 0 9

02 November 2002 0 4 0 0 0 4

22 November 2002 5 10 1 0 0 16

02 December 2002 0 0 0 0 0 0

18 December 2002 6 11 2 0 0 19

01 February 2003 1 0 0 0 0 1

14 February 2003 0 1 0 0 0 1

18 February 2003 1 0 0 0 0 1

04 March 2003 0 0 0 0 0 0

26 March 2003 0 0 1 0 0 1

27 March 2003 0 5 1 0 0 6

12 April 2003 1 9 1 0 0 11

16 April 2003 0 13 0 0 0 13

52 Appendix 13 Grey seal abundance at Trwyn Cilan Date f-male f-female f-juvenile f-pups f-UID Total

22 August 2002 0 0 0 0 0 0

01 September 2002 0 1 0 0 0 1

09 September 2002 0 1 0 1 0 2

17 September 2002 2 1 0 1 0 4

23 September 2002 1 8 0 8 0 17

24 September 2002 2 8 0 8 0 18

06 October 2002 2 7 0 7 0 16

11 October 2002 2 3 0 4 0 9

31 October 2002 0 1 0 0 0 1

16 November 2002 1 1 0 0 0 2

06 December 2002 2 3 0 0 0 5

17 December 2002 1 2 1 0 0 4

20 February 2003 1 1 1 0 0 3

16 March 2003 0 0 0 0 0 0

26 March 2003 0 0 0 0 0 0

28 March 2003 1 0 0 0 0 1

05 April 2003 1 1 0 0 0 2

53 Appendix 14 Grey seal abundance at Trwyn y Gader (Carmel Head) Date f-male f-female f-juvenile f-pups f-UID Total

30 July 2002 0 0 0 0 0 0

06 August 2002 0 0 0 0 0 0

19 August 2002 0 0 0 0 0 0

31 August 2002 0 0 0 0 0 0

06 September 2002 0 0 0 0 0 0

13 September 2002 0 0 0 0 0 0

20 September 2002 1 1 0 0 0 2

27 September 2002 1 1 0 1 0 3

07 October 2002 0 1 0 1 0 2

13 October 2002 0 0 0 1 0 1

27 October 2002 0 0 0 1 0 1

03 November 2002 0 0 0 0 0 0

18 November 2002 0 0 0 0 0 0

03 December 2002 0 0 0 0 0 0

13 February 2003 0 0 0 0 0 0

16 February 2003 0 0 0 0 0 0

23 March 2003 0 0 0 0 0 0

54 Appendix 15 Grey seal abundance at West Hoyle Sandbank, Dee Estuary Date Total

11 September 2002 154

30 September 2002 193

26 November 2002 116

22 January 2003 81

23 January 2003 92

24 January 2003 77

27 January 2003 54

28 January 2003 63

29 January 2003 51

30 January 2003 72

10 February 2003 46

22 February 2003 94

23 February 2003 108

19 March 2003 164

11 July 2003 330

55 Appendix 15a Grey seal abundance at West Hoyle Sandbank, Dee Estuary using non-standard methods Date Total

03 January 2002 56

04 January 2002 30

05 January 2002 50

06 January 2002 90

08 January 2002 90

14 January 2002 118

25 January 2002 38

03 February 2002 35

15 February 2002 126

28 February 2002 83

12 March 2002 252

16 March 2002 210

17 March 2002 42

20 March 2002 120

21 March 2002 212

25 March 2002 163

06 April 2002 101

07 April 2002 220

15 April 2002 270

16 April 2002 230

17 April 2002 190

25 April 2002 220

26 April 2002 203

27 April 2002 244

28 April 2002 235

56 29 April 2002 115

30 April 2002 44

02 May 2002 260

06 May 2002 236

08 May 2002 236

10 May 2002 275

11 May 2002 518

12 May 2002 350

16 May 2002 190

17 May 2002 150

19 May 2002 432

20 May 2002 348

01 June 2002 457

04 June 2002 420

09 June 2002 240

15 June 2002 170

29 June 2002 250

09 July 2002 412

11 July 2002 386

14 July 2002 31

21 July 2002 424

27 July 2002 190

28 July 2002 105

29 July 2002 120

03 August 2002 120

05 August 2002 190

06 August 2002 210

08 August 2002 190

09 August 2002 230

57 10 August 2002 454

15 August 2002 1

16 August 2002 210

17 August 2002 180

18 August 2002 220

21 August 2002 310

22 August 2002 300

26 August 2002 156

27 August 2002 300

28 August 2002 399

30 August 2002 160

31 August 2002 135

01 September 2002 200

02 September 2002 120

03 September 2002 97

04 September 2002 150

05 September 2002 216

06 September 2002 260

07 September 2002 305

08 September 2002 210

09 September 2002 210

10 September 2002 235

11 September 2002 230

12 September 2002 240

13 September 2002 160

15 September 2002 120

16 September 2002 160

18 September 2002 120

19 September 2002 210

58 20 September 2002 120

22 September 2002 101

23 September 2002 120

24 September 2002 155

25 September 2002 280

26 September 2002 212

27 September 2002 245

28 September 2002 173

09 October 2002 87

10 October 2002 70

11 October 2002 126

12 October 2002 84

13 October 2002 170

14 October 2002 112

15 October 2002 105

23 October 2002 50

26 October 2002 45

09 November 2002 120

23 November 2002 210

30 November 2002 120

07 December 2002 150

13 December 2002 112

15 December 2002 40

31 December 2002 50

59 Appendix 16 Grey seal abundance at Ynys Dulas Date f-male f-female f-juvenile f-pups f-UID Total

02 August 2002 1 19 1 0 0 21

03 August 2002 0 0 0 0 36 36

02 September 2002 2 14 3 0 0 19

12 September 2002 13 17 7 0 0 37

20 September 2002 6 19 3 0 0 28

03 October 2002 7 24 5 0 0 36

10 October 2002 11 23 5 0 0 39

05 November 2002 34 60 21 0 0 115

13 November 2002 32 69 6 0 0 107

16 December 2002 57 54 17 0 0 128

13 January 2003 69 37 17 0 0 123

05 February 2003 50 74 15 0 0 139

13 February 2003 39 74 10 0 0 123

15 February 2003 36 62 6 0 0 104

17 March 2003 74 35 9 0 0 118

25 March 2003 36 58 6 0 0 100

03 April 2003 58 43 11 0 0 112

17 April 2003 8 2 0 0 0 10

60 Appendix 17 Grey seal abundance at Ynys Seiriol (Puffin Island) Date f-male f-female f-juvenile f-pups f-UID Total

01 August 2002 14 13 7 0 0 34

18 August 2002 12 4 10 0 0 26

28 August 2002 9 5 11 0 0 25

02 September 2002 17 6 7 0 0 30

14 September 2002 13 8 11 0 0 32

22 September 2002 5 4 2 0 0 11

07 October 2002 8 8 10 0 0 26

10 October 2002 3 1 8 0 0 12

13 November 2002 53 42 11 0 0 106

03 December 2002 18 11 9 0 0 38

16 December 2002 59 47 21 0 0 127

31 January 2003 68 42 14 0 0 124

04 February 2003 69 28 22 0 0 119

12 February 2003 73 44 13 0 0 130

18 March 2003 14 8 6 0 0 28

26 March 2003 40 13 3 0 0 56

04 April 2003 23 7 7 0 0 37

16 April 2003 13 3 3 0 0 19

61 Appendix 18 Grey seal abundance at Ynysoedd y Moelrhoniaid (The Skerries) Date f-male f-female f-juvenile f-pups f-UID Total

16 August 2002 15 18 3 0 0 36

15 September 2002 12 23 4 0 0 39

27 September 2002 12 16 4 0 0 32

05 November 2002 5 19 1 12 0 37

15 November 2002 6 18 5 11 0 40

11 February 2003 10 13 1 0 0 24

21 February 2003 12 31 5 0 0 48

27 March 2003 13 29 7 0 0 49

06 April 2003 8 28 6 0 0 42

Appendix 19 Grey seal abundance at Ynys Enlli (Bardsey Island) Date f-male f-female f-juvenile f-UID f-pups Total

08 August 2002 51 107 7 0 0 165

21 August 2002 28 33 5 49 0 115

22 August 2002 0 0 0 67 0 67

23 August 2002 29 34 20 0 0 83

24 August 2002 45 51 48 27 0 171

25 August 2002 45 79 36 46 0 206

26 August 2002 32 103 30 44 0 209

27 August 2002 23 71 45 35 0 174

29 August 2002 17 43 49 34 0 143

01 September 2002 17 36 23 41 0 117

02 September 2002 18 31 20 60 0 129

03 September 2002 15 14 3 73 0 105

62 04 September 2002 17 45 28 18 0 108

05 September 2002 40 52 30 11 0 133

06 September 2002 41 59 34 14 0 148

07 September 2002 33 42 32 10 0 117

08 September 2002 37 62 26 2 1 128

18 September 2002 7 11 0 38 3 59

25 September 2002 7 8 1 0 4 20

05 October 2002 25 35 5 11 4 80

12 October 2002 8 9 1 0 5 23

05 November 2002 26 12 6 3 4 51

11 November 2002 33 1 34

25 November 2002 59 42 5 0 1 107

26 November 2002 46 1 47

05 December 2002 81 0 81

11 December 2002 59 0 59

18 December 2002 73 0 73

26 December 2002 67 0 67

01 January 2003 102 0 102

06 January 2003 64 0 64

07 January 2003 92 0 92

26 July 2003 69 58 5 17 0 149

27.July 2003 71 75 7 27 0 180

28 July 2003 51 69 5 20 0 145

29 July 2003 77 76 10 19 0 182

30 July 2003 100 96 8 24 0 228

31 July 2003 48 60 8 21 0 137

01 August 2003am 59 34 3 61 0 149

63 01 August 2003pm 53 53 2 18 0 126

02 August 2003am 62 51 14 25 0 152

02 August 2003pm 92 92 11 0 0 187

03 August 2003 53 41 3 21 0 118

04 August 2003 61 81 5 0 0 147

Appendix 19a Ynys Enlli (Bardsey Island): the detail of the winter counts, Dec 2001 to Jan 2003 Date Henllwyn First Cove To Maen du Maen Porth Porth Total South (SE) du Hadog Solfach

26.12.01 18 102 13 15 0 0 148

02.01.02 15 39 5 1 0 0 60

09.01.02 48 46 3 0 0 0 97

16.01.02 79 25 8 0 0 0 112

25.01.02 48 12 5 0 1 pup 0 66

30.01.02 114 9 0 0 0 0 123

08.02.02 78 18 1 0 0 1 98

21.02.02 51 61 4 2 0 0 118

11.11.02 8 18 6 1 0 0 33

26.11.02 14 20 12 0 0 0 46

05.12.02 28 34 17 4 0 0 83

11.12.02 12 29 7 11 0 0 59

18.12.02 24 39 8 2 0 0 73

26.12.02 13 27 11 16 0 0 67

01.01.03 61 21 14 6 0 0 102

06.01.03 34 18 12 0 0 0 64

07.01.03 47 26 19 0 0 0 92

64 APPENDIX 20 SITE SPECIFIC NOTES

YNYS ENLLI (Bardsey Island)

Ynys Enlli/Bardsey Island, situated about 3 kilometres south-west of Penrhyn Llyn/Lleyn Peninsula, is girdled by 7 tide races, consists of rocky shores and occasional sand or shingle beaches, often backed by cavelets (i.e. very small caves). It is the second most important seal site, year-round, after West Hoyle sandbank.

Nearly all seals use haul-out sites south of Cafn or on the smaller island to the west of Enlli/Bardsey Island, Carreg yr Honwy.

The nearest seal site to Ynys Enlli/Bardsey Island is the Gwylans Coast.

During the summer months, Henllwyn, facing approximately eastward and therefore sheltered from the prevailing south-westerly winds, is usually the main haul-out site for seals on the main island. Here, the seals use the rocky foreshore, narrow shingle beaches and tidal islets. First Cove South was the name chosen to distinguish the rocky shore and narrow shingle beach, which is, in effect, a continuation of Henllwyn southward. Both sites function also as nurseries for seal pups.

Farther south again lies the crooked inlet named for this survey as Lighthouse Cove East, which opens to the north-east. Here, bedrock and massive boulders shelter a small beach, also used as a seal pup nursery.

To Maen-du (SE) describes Ogof Diban, a sheltered cove shaped like a dog-leg, Pen Diban, which includes a tidal spit extending seaward and the south-easternmost inlet, called Maen-du (SE) for this survey. Seal pups are born here.

Maen-du describes the southern extremity of the island, an area of bedrock.

Porth Hadog lies on the exposed west shore, comprising a small shingle beach and sloping bedrock, a site rarely used by the seals.

Solfach comprises a predominantly sand and rocky shore cove, including a number of small tidal islets. Seals also use rocks and islets at the southern extremity of the cove.

All sites here used by seals are accessible from the land, except for Carreg yr Honwy, the islands that lie west of Porth Solfach.

Counts of seals hauled out on Carreg yr Honwy can be made from the summit of Mynydd Enlli, using a telescope. Seals here are easily disturbed when a boat is used to make passage by these islands. However, only by using a boat do you stand a chance of making an accurate count. If a boat is used, it is necessary to give these rocks as wide a berth as is consistent with making the accurate count.

Best time to scan or visit the site is low tide.

Ogof Morlo can be reached most easily by boat. Thereafter, climbing a few metres up from the shore and entering near the high point of the entrance opening, makes access to the cave. The most recent rockfall in this cave occurred in 2002, rendering access more difficult and dangerous than previously. Best time to visit the cave is on a low spring tide.

65 Ogof Diban and the adjoining beach can be reached by clambering down the south side of the cove, or down the narrow spit, partly grass-covered, which divides the two beaches. Pups have been found well-concealed in cavities among the rocks, making them invisible from the clifftop.

At all other sites, especially Bae y Rhigol and Henllwyn, it is essential that observers should not simply scan for seals from the clifftop but should clamber down to the beaches. Small ‘cavelets’ and overhangs at the back of beaches and gullies are a feature of the island and these are used as resting places, especially by pups.

PENRHYN LLYN/LLEYN PENINSULA: South coast

Gwylans Coast The Gwylans Coast is situated on the south-west coast of the Penrhyn Llyn/Lleyn Peninsula. It stretches from Pen y Cil in the west to Trwyn Talfarach in the east, at the eastern limit of Porth Neigwl/Hell’s Mouth. Here, the coast consists of a series of sea caves and small, remote beaches, as well as the two islands, Ynys Gwylan-fawr and Ynys Gwylan-bâch.

The nearest seal sites to the Gwylans are nearby: Ynys Enlli/Bardsey Island in the west, Trwyn Cilan in the east.

The caves and the beaches between Trwyn y Penrhyn and Ebolion are best visited at half-tide, as they become more difficult to access at low tide. The one exception is the small, L-shaped cave at SH18732530, which must be visited at low tide.

The caves between Ebolion and Ogof Llwyd (East) are best visited between two hours before and after low tide. At Ogof Lwyd East, it is necessary to clamber over the massive boulders that have fallen and mainly blocked the entrance. Although it seems unlikely that seals might be found within, this is a site where pupping occurs. Entry and exit are achieved only with great exertions by the seals, who lever themselves up and out through a jagged hole at all states of the tide except high – when the beaches within are under water.

Ogof Morlo can only be visited when quiet sea conditions prevail, at low tide, ideally on a spring tide. Just before reaching the beach, the researcher will find the cave passage almost blocked by a fin-shaped rock, which can only be squeezed by awkwardly on the low tide.

The beaches between Clog Cidwm and Porth Llawenan can be visited at any state of the tide.

The Gwylans can be visited at any state of the tide, but if abundance counts are being made, visits must be made at low tide. A tide-race runs inside Ynys Gwylan-fawr at low tide and between the two islands.

Pen y Cil

A sequence of beaches and sea caves apparently, but not actually, inaccessible from the land, situated on the west shore of Aberdaron Bay.

All sites, which are rarely used by the seals, are best visited at high tide.

66 Trwyn Cilan

Trwyn Cilan is the longest headland jutting from the south coast of Penrhyn Llyn/Lleyn Peninsula. A tide race brushes its tip and run along its west shore as far as Carreg y Tir. Several highly exposed sea caves run deeply into the high cliffs. As elsewhere (e.g. the Gwylans Coast and the Ynys Arw/North Stack Coast), more sites are used in the breeding season than at any other time of year.

Sea conditions make access to these sites particularly difficult.

The nearest seal sites are the Gwylans Coast in the west and the Tudwals in the east.

All sites are best visited at half-tide.

A quite powerful tide-race runs from a point between Ogof y Tir and Carreg y Tir, out to the tip of Trwyn Cilan.

Tudwals and Carreg y Trai

This cluster of sites is situated at the south end of St.Tudwal’s Road. Ynys Tudwal West is situated about 400 metres off the mainland shore at the south end of St.Tudwal’s Road. Neighbouring Ynys Tudwal East is situated about 800 metres offshore and slightly to the north. About 400 metres to the south-east of Ynys Tudwal East lie two tidal rocks, both called Carreg y Trai. Together, the Tudwals comprise the third most important summer haul- out site for seals in the North Wales region (after the West Hoyle Sandbank and Ynys Enlli/Bardsey Island).

The nearest seal site to the Tudwals is Trwyn Cilan.

Carreg y Trai (North) is the more low-lying of two tidal islets. Being low-lying, it is even more subject to wave action than Carreg y Trai (South).

It appears that whenever the sea is relatively calm, during the period April to October seals largely ignore the Ynys Tudwals (West and East) haul-out sites and use the two Carreg y Trai sites (North and South), these being the most remote and seaward of the sites.

Ynys Tudwal (East) has sheer cliffs, sea caves and massive ledges at the south end. Along the east shore there are sloping ledges. Seals are mainly confined to the east, south-east and south-west shores.

Ynys Tudwal (West), the more landward of the two islands, is composed of cliffs, sea caves and massive ledges, as well as a landing place (at the north-east end) originally constructed to allow easy access to the lighthouse, which is situated on the high point of the island. Seals are mainly confined to the east, south-east and south-west shores.

Sites are best visited at low water on a spring tide.

There are no tide races but powerful wave action occurs at the south end of both Tudwals in winds of force 4 and stronger when they are blowing from the southern quarter.

67 Glanllynnau Skerries

East of Pwllheli and west of the mouth of Afon Dwyfor, the long beach includes access to a holiday camp. The beach is used only lightly. Seals use a few offshore rocks for hauling out in low numbers mainly in the summer months.

PENRHYN LLYN/LLEYN PENINSULA: North Coast

Porth Widlin to Traeth Penllech

Situated on the north-west coast of Penrhyn Llyn/Lleyn Peninsula, this stretch is only occasionally and lightly used by seals. Local fishermen speak of it having been used as a breeding location in the 1990s, although this was not confirmed by the recent surveys (Westcott, 2002; Westcott & Stringell, 2003).

This coast lies below a (currently) lightly used cliff-top footpath and is, generally, easily accessible. Occasional beaches are separated by extensive stretches of rocky foreshore.

The nearest seal sites are Ynys Enlli/Bardsey Island to the west and Rhosgor to the east.

Rhosgor

Rhosgor is an unusual seal haul-out site in that it lies below low cliffs on the north coast of Penrhyn Llyn and is locally well known as a seal site. It is situated close to a coastal footpath, and the rocks used by the seals are situated to seaward of an attractive shingle beach. It lies below a farm to which caters for caravans and campers during the summer.

The site consists mainly of rocky foreshore, sometimes backed by shingle and cobble beaches.

The nearest seal site is at Carreg Ddû, about 4 kilometres to the north.

Sites best visited within two hours of low tide. Best approached overland, via Hirdre Fawr Farm (Mr.Williams), where the farmers have always been very helpful

The site is best visited at low tide.

Carreg Ddû

This site, consisting of two islands and a number of small, emergent rocks close to the tip of Trwyn Porth Dinllaen.

The nearest seal haul-out site, approximately 4 kilometres to the south-west, is at Rhosgor.

YNYS SEIRIOL/PUFFIN ISLAND

Ynys Seiriol/Puffin Island is separated from Ynys Môn/Anglesey (at Trwyn Pen Dinmon) by a narrow strip of water where a fierce tide race runs. The island is, in effect, a massif of rock

68 with great bedrock slabs and narrow inlets along its west shore, shingle and boulders at its south end, ledges and boulders along the east shore with boulders, slabs and inlets at the north end. Seal assemblies are confined almost exclusively to the north tip of the island through the year.

The nearest seal assembly site lies more than 15 kilometres to the north, at Ynys Dulas.

The island should be visited at low tide.

Seals nearly always confined within 250 metres of the north tip of the island

YNYS DULAS

Ynys Dulas lies about a kilometre east of the Dulas Estate, off the east coast of Ynys Môn/Anglesey. It is a low-lying, rocky island, capped by a tower that functions as a daymark.

The nearest seal assembly site lies more than 15 kilometres to the south, at Ynys Seiriol/Puffin Island.

The island should be visited at low tide.

A noticeable but relatively weak tide race runs near the south-west tip of the island

YNYSOEDD Y MOELRHONIAID/THE SKERRIES

The main island and its attendant islets are situated about 4 kilometres north-west of the north-west tip of the main island of Ynys Môn/Anglesey, of the seal site of Trwyn y Gader/Carmel Head. Five different tide races girdle these islands.

There is one beach on the west shore and four beaches on the east shore. In addition, Ynys Arw is connected to the main island of Ynysoedd y Moelrhoniaid/The Skerries by a beach at mid- and low tide. These tend to be used by seals only in the breeding season. Otherwise, seals here haul out on rocky offshore islands.

For pup counts, if a boat is being used, Ynysoedd y Moelrhoniaid is best visited at high tide. If a boat is not being used, then visits should be made two hours either side of low tide – while it is still possible to walk from islet to islet.

Counts should be made at low tide.

TRWYN Y GADER/CARMEL HEAD

Trwyn y Gader/Carmel Head is situated at the north-west extremity of the main island of Ynys Môn/Anglesey. Skirted by fierce tide races, it consists of a number of unexpectedly sheltered beaches and one long sea cave. The area covered by survey work extended east as far as Cemlyn Bay by way of a succession of beaches.

A coastal footpath runs above the entire local coastline. In 2002, there was a considerable amount of fly-tipping of fencing materials and of a farm vehicle.

69 The nearest seal site is Ynysoedd y Moelrhoniaid, about 4 kilometres to the north-west.

Sites best visited at mid- tide.

PORTH BRIBYS to YNYS FYDLYN

A sequence of beaches and sea caves, rarely used by seals but relatively easy to access from the land and best visited at low tide

YNYS ARW/NORTH STACK

The Ynys Arw Coast stretches from Ynys Lawd/South Stack in the south to Ynys Arw/North Stack and west to Porth Namarch, near Caer Gybi/Holyhead harbour on Ynys Cybi/Holy Island. This is a coast of mainly inaccessible small, remote beaches and the longest and most complex sea caves in the North Wales region. However, the two most important features are the strength of the fierce tide race, which skirts this coast at greatest force of Ynys Arw/North Stack itself, and the dangerous swells, which inundate sea, cave beaches on middling or high tides. The swells are generated several times each day by the passage of the high-speed ferries using Caer Gybi/Holyhead.

The nearest seal sites to the Ynys Arw Coast are about 10 kilometres to the north-east across Bae Caergybi/Holyhead Bay, at Ynysoedd y Moelrhoniaid/The Skerries and at Trwyn y Gader/Carmel Head.

North-facing sites (including the headland cave and cleft system) may be visited two hours either side of low tide, as can Ogof Gogarth.

The three west-facing caves just south of Parliament House (which may be visited at any state of the tide) are best visited at low water on a spring tide. Even a slight sea swell makes access to the northernmost of these three caves (Ogof Morlo) particularly difficult.

WEST HOYLE SANDBANK

The West Hoyle Sandbank is situated near to the mouth of the Dee Estuary and opposite Hilbre Island. It consists exclusively of fine sand. The seals always haul-out in the same place on the sandbank, adjacent to water that is approximately 20 metres deep. It is the most important seal haul-out site in the North Wales region. It is also exceptional as a haul-out site in the region in being a sandbank.

This is the most isolated haul-out site in the North Wales region, the nearest neighbouring site being Ynys Seiriol/Puffin Island, off the south-east tip of Ynys Môn/Anglesey.

Access can be achieved by boat or wave ski only, most easily from the Welsh shore at Greenfield.

At low tide there is a complex pattern of sandbanks and the flow of the river is strong.

70 APPENDIX 21 RISK ASSESSMENT

General Health & Safety Issues

Prior to every trip, the line manager should be informed verbally about where you are going, what time you are leaving and what time you expect to return. Included in this communication should be agreement between the two about the weather forecast and the time of low tide.

Site visits should always be undertaken by a minimum of two people.

Most correctly, sea caves should be visited only on a falling tide. However, if sea conditions are benign (if the sea is calm or slight), common sense should prevail and, so long as achieving landfall and re-launching present no abnormal difficulties, explorations can be made on the first half of a rising tide.

If abseiling or climbing is used to access beaches, this should take place only after thorough training.

In a logbook, recall all misadventures while in the field as well as crucial site-specific detail. For example, rocks in certain caves may always be covered with a algal film, making them particularly slippery. This information will inform other fieldworkers and may assist rescuers, at need.

Where access to sites is from the land, perhaps through vegetation, beware holes in the ground (shearwaters, puffins, rabbits) and beware catching a foot between rocks.

Beware grass, which can be slippery and which should not be trusted as providing a secure hand-hold.

Using a wave ski to reach remote sites inaccessible from land

The wave ski, constructed out of polypropylene, is a little less than three metres long and about 0.75 metres wide. On the underside, near to the tail, there is a skeg, the length of which can vary between 10 and 25 centimetres, which assists with steerage. On the topside, there is a hollow for a seat, behind which are two canvas handles. Farther forward, there are two more hollows where the heels rest. Just forward of the heel hollows, there are two padded loops under which the toes rest. Attached to an anchorage point close to the nose of the ski is one end of an ankle leash.

The ski is propelled using a paddle, approximately 2 metres long, with a carbon fibre stem. It is imperative that the paddle is as near as possible indestructible and that it is made of a material that will not rust or rot.

The paddle is attached by a length of unbreakable line to the forward anchorage point, by means of a bowline knot, and to the mid-point of the paddle stem by three turns and two half- hitches. This is to ensure that if the rider falls off the ski, then the ski and the paddle remain together: there is only one item to retrieve.

The rider is attached to the ski at all times by an ankle leash. One end is secured to the forward anchorage point, the other secured by Velcro around the ankle of the rider. Connection to the ski by way of the ankle leash ensures that if the rider falls from the ski, the two cannot be separated. The ski is easily retrieved and easily remounted.

71 If the rider falls from the ski close to the shore, connection to the ski by way of the ankle leash means that it could be used as a shield against injury on the rocks.

As important as it is that the rider be attached to the ski by an ankle leash, it is equally important to remember to remove the leash when landfall has been secured – to prevent misadventure while walking away still attached to the ski.

The ski itself is extremely durable, the polypropylene construction ensuring that it is indestructible in the open sea conditions that the fieldworker may encounter.

Equipment, stored inside sealed dry bags, can be anchored to the forward anchorage point. There, it lies between the legs and serves a secondary function as a partial shield against waves breaking toward the body of the rider.

Weather & sea conditions: Conditions under which the wave ski will be used

Various weather forecasts must be consulted before the wave ski is launched.

It is recommended that the following sources be consulted regarding the forecast for up to several hours beyond the expected conclusion of the day’s work:

• Your own barometer, anemometer along with cloud type and movements.

• The shipping forecast for the local and surrounding sea areas. If the weather is coming from the south-west, then note should be made of the weather conditions in that quarter.

• The local weather forecast.

• Ceefax2: page 404, which gives current wind direction and speed, pressure, temperature and prevailing weather for nearby places. In North Wales, for example, consult information for Aberystwyth, the Isle of Man and Belfast.

The wave ski will be used in only calm or slight to moderate sea conditions and will not be used when the wind exceeds force 4 (Beaufort Scale), onshore.

Where the wind is offshore, the wave ski can be used so long as the surface of the sea remains relatively flat.

If conditions develop during the course of the voyage, the nearest safe haven will be sought as soon as sea conditions develop from slight to moderate. In practise, this is when the number of white horses becomes widespread.

A safe haven here means the nearest landfall where the fieldworker can both take refuge and, if necessary, decide to abandon work for the day and gain access to a footpath or road.

On each trip, once embarked and c.200 metres offshore, the state of sea conditions should be reconsidered, bearing in mind that what appears to be a calm sea from the beach may be a wilder sea when seen from the horizon; and vice versa. Don’t be brave; be careful.

72 Tides

When planning voyages to any site, thought needs to be given to the time of local high and low tides and the phase in the lunar cycle between spring and neap tides. It is essential that a timepiece be carried on every trip.

In addition to tide height, it is imperative that local information be sought regarding the existence and nature of any local tide races before any fieldwork is undertaken. Ideally, this will be obtained from local inshore fishermen, the coxswain of the local lifeboat or the local harbour master. Information can also be obtained by studying Admiralty charts and tidal stream charts contained in the pages of a nautical almanac.

Making passage

At the outset, notify the coastguard, using VHF radio, of time of details of craft being used, place of launching, destination and expected time of return. Upon returning, notify coastguard of that fact.

Inform line manager of the same information.

Although much local knowledge can be gleaned from various local sources, those using the wave ski will gain most confidence if they can compile it out of their own personal experience.

Summer is the ideal time to begin the compilation of such knowledge, the ideal time to explore those stretches of coast where the most part of their work is to be carried out. The period around low tide is the best time to explore the area. It will give the fieldworker the chance to see the lie of the land and to discover sites where potentially dangerous wave action could occur when the tidal level is higher.

Close attention should be given to the nature of the surface of the sea, noting the warning signs of submerged rocks lying close to the surface or where a tidal race begins. The direction and rate of flow should be noted by watching water movement by every fisherman’s float passed en route as well as by watching your rate of progress against landmarks.

Attention should be given to local wind direction and wind speed, especially in relation to the undulations of the coastline, most especially around headlands and below valleys. The nature of any cloud massing along the windward horizon should also be kept under continual review. Whatever any forecast predicts, the fieldworker should remain alert to the realities of the moment. Forecasts are reasonable guesses, not promises.

Potential injuries

• Head wounds. If a helmet is not worn when working in sea caves, fieldworkers may suffer a variety of injuries, the mildest of which is bruising. Cuts could bleed heavily. The worst likely injuries would result in concussion and/or a fractured skull.

Therefore, it would be important to carry in the First Aid kit the means of staunching a heavy flow of blood.

• Broken bones. Apart from the skull, many bones are susceptible to breakage in the

73 relatively difficult conditions that prevail in caves. Bones of the feet and hands, tibia and fibula may be especially vulnerable, resulting from a fall or from a foot becoming trapped among boulders, perhaps as a result of reacting too violently having been startled by the appearance or proximity of a seal. It may also arise where a fieldworker pays more attention to the protection of valuable equipment (e.g. camera, camcorder) than to personal safety.

• Sprains and strains. These may arise from the same situations that could lead to broken bones.

74 APPENDIX 22 ENVIRONMENTAL INFLUENCES ON SURVEY EFFORT

The principal factors determining the accessibility of sites used by grey seals in North Wales are the direction and strength of the wind that, in turn, determine the state of the sea.

Monthly wind direction and speed, 2001

Wind direction in the two and a half years during which survey work was being carried out shows the predominant wind to be from the south to west quarter, followed by winds from the north to west quarter.

Outside of the generally westerly air flow in 2001, during the period December to May, winds from a generally easterly direction blew far more often than in the other half of the year.

20 18 16 14 12 N - E S - E 10 S - W 8 N - W

days per month 6 4 2 0 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Figure 24 Monthly wind direction and speed, 2001

75 Monthly wind direction and speed, 2002

N - E 15 S - E S - W 10 N - W days per month 5

Jul Jan Feb Mar Apr May Jun Aug Sep Oct Nov Dec

Figure 25 Monthly wind direction and speed, 2002

For the greater part of 2002, again the predominant winds blew from the south to west quarter, followed by winds from the north to west quarter. However, between September and December, the predominant wind came from the south to easterly quarter – something that was very helpful in making especially sea cave nursery sites generally more easily accessible than would normally be the case. Indeed, in December, the generally easterly airflow was heavily dominant.

Monthly wind direction and speed, January to July 2003

20 N - E S - E 15 S - W N - W 10 days per month

0 Jan Feb Mar Apr May Jun Jul

76 Figure 26 Monthly wind direction and speed, January to July 2003 Through the first seven months of 2003, the airflow came predominantly from the southerly quarter. Winds from the south to east predominated from February to April and in June, while winds from the south to west predominated in the remaining three months.

Days per month when sea state was calm (Beaufort Scale 0-2), 2001 to July 2003

10 2001 8 2002 6 2003 no. of days 4

Jan Apr Jun Jul Date Feb Mar May Aug Sep Oct Nov Dec

Figure 27 Days per month when sea state was calm, January 2001 to July 2003

During the 31 months that sea state records were kept, there were only four months when the sea state was calm for 10 days or more; when conditions for gaining access to sites were perfect. Generally, there were five or less such days each month.

77 Days per month when sea state was slight (Beaufort Scale 2-3), 2001 to July 2003

10 2001 8 2002 6 2003 no. of days 4

Jan Apr Jun Jul Date Feb Mar May Aug Sep Oct Nov Dec

Figure 28 Days per month when sea state was slight, January 2001 to July 2003

On average, there were about 10 days a month when sea conditions were slight. Under these conditions, gaining access to sites was very easy.

Days per month when sea state was moderate (Beaufort Scale 4-5), 2001 to July 2003

20 18 16 14 12 2001 10 2002 8 2003 no. of days 6 4 2 0

Jan Apr Jun Jul Date Feb Mar May Aug Sep Oct Nov Dec

Figure 29 Days per month when sea state was moderate, January 2001 to July 2003

78 On average, there were about 10 days in every month when sea conditions were moderate. In these conditions, gaining access to sites is usually difficult and there is a variable measure of danger, depending upon whether the shore is rocky and whether landings are being attempted on a lee or windward shore. It is possible, some of the time, to work in such conditions although the trend toward an ever more safety conscious, or overly safety conscious working framework is likely to see work in such a sea state forbidden

Days per month when sea state was rough (Beaufort Scale 6 and above), 2001 to July 2003

Such seas tend to be mainly a winter phenomenon but can also occur for periods of some weeks in autumn, disrupting the search for seal pups.

15 2001 2002 10 2003 no. of days

Jan Apr Jun Jul Date Feb Mar May Aug Sep Oct Nov Dec

Figure 30 Days per month when sea state was rough, January 2001 to July 2003

There is a widespread perception that sea conditions are rougher in the autumn and winter than in the summer. Nevertheless, this can also be a period of research opportunity (apparently neglected in past seal research in North Wales).

In this survey, there were many days when autumn and winter seas were rough and the research effort was frustrated. During November 2002, for example, seas were generally moderate or rough (for 22 days of the month). Combined with the availability of only a short number of daylight hours, this meant that site access was patchy.

No sites were visited during January 2003 because reports were being written at a time when sea conditions happened to be difficult (sea conditions were moderate or rough on 22 days of this month).

It is also the case with sites which are inundated by the sea in moderate to rough conditions, as with most sea cave sites and islands such as Carreg y Trai (north and south) and Carreg yr Honwy to the west of Ynys Enlli/Bardsey Island, that seals avoid hauling out there.

79 However, at sites like Ynys Dulas or Ynys Seiriol/Puffin Island, in moderate and rough seas, seals continue to haul out around the low tide period, on the lee shore and on sites higher up the shore than are normally used.

20 2001 15 2002 2003 no.of days 10

Jan Apr Jun Jul Date Feb Mar May Aug Sep Oct Nov Dec

Figure 31 Number of days per month that the sea state for North Wales was Beaufort Wind Scale > 4 (moderate to rough) between 2001 and 2003.