Fifth otter survey of England Technical report

Transcription

1 Fifth otter survey of England Technical report

2 We are The Environment Agency. It's our job to look after your environment and make it a better place for you, and for future generations. Your environment is the air you breathe, the water you drink and the ground you walk on. Working with business, Government and society as a whole, we are making your environment cleaner and healthier. The Environment Agency. Out there, making your environment a better place. Published by: Environment Agency Rio House Waterside Drive, Aztec West Almondsbury, Bristol BS32 4UD Tel: enquiries@environmentagency.gov.uk Environment Agency All rights reserved. This document may be reproduced with prior permission of the Environment Agency. Author - Andrew Crawford (Environment Agency) Project Manager - Graham Scholey (Environment Agency) Main survey contractors - Elizabeth Andrews, Hilary Marshall, John Martin, Robin Roper, Andy Rothwell, Mark Satinet Alternate squares surveyors - see acknowledgements Further copies of this report are available from our publications catalogue: or our National Customer Contact Centre: T: E: enquiries@environment-agency.gov.uk.

3 Summary The fifth national otter survey of England has for the first time achieved comprehensive coverage of the whole country. Two field survey techniques were used in parallel full surveys for sites investigated in previous national surveys (the main survey), and spotchecks for all the alternate 50km squares not covered in the previous surveys. The main survey was carried out between July 2009 and March Six highly experienced otter surveyors examined 3327 sites across the country using thirty-eight 50 x 50 km squares (the north-west and south-east quarters of each 100km square) as a sampling grid. Footprints and droppings (spraints) represent the most distinctive signs of otter and their presence within the standard 600m survey length of river represented a positive site record. Signs of otters were recorded at 1874 (56%) of sites in the main survey. In addition, the alternate squares spot-checks undertaken within the same time frame proved otter presence in 553 of the km squares surveyed. Direct comparison of positive records from 2940 sites used in all five national surveys reveals the recovery of otters from virtual extinction in most of England during the early 1970s. Positive site records increased from 5.8 per cent in , to 9.6 per cent in ; 23.4 per cent in ; 36.3 per cent in and 58.8 per cent in Recovery has continued in all but the very south-east where no signs were found in Kent or most of Sussex. Re-colonisation from strongholds in south-west and northern England and Wales has now been consolidated across much of the country and continues to drive recovery. Since there has been a major link-up across several river catchments. For example, there is no longer a gap in otter distribution between the south-west, south Wales, lower Wye and Severn and upper Thames. Similarly, there is now a link between populations in East Anglia, the River Trent catchment, Yorkshire and the traditional Northumbria stronghold. The pattern of recovery differs at a regional scale, with Thames showing the biggest increase in positive signs since In South-West Region and the River Wye catchments otter populations have probably reached a level approximating to carrying capacity, with those in Northumbria, Cumbria, Wessex and the upper Severn close to that. Elsewhere, further recovery and consolidation will take more time. Recovery has been in response to three main factors, the ban on pesticides that caused extinction of otters from many parts of England in the 1960s and early 1970s, legal protection for the otter since 1978, and the significant improvement in water quality in previously fishless rivers since the 1970s. Re-introduction programmes of captive bred and re-habilitated otters in certain parts of the country are likely to have speeded up the recovery locally in East Anglia, Yorkshire and the upper Thames. However the majority of the recovery has been the result of natural expansion from the remnant populations. The prospects are for full recovery across England probably within the next two decades or so. This represents a major success story for pollution control, as well as investment by the water industry and efforts by landowners and river managers to improve river and riparian habitat. Tracking the otter s recovery has demonstrated the benefits of long-term monitoring and the use of this iconic species to raise awareness of pollution problems and the benefits of action to improve the environment.

4 The revised (2006) Biodiversity Action Plan (BAP) target for otters in England was for at least km squares to show signs of otter occupation by 2010 and for km squares to show signs of otter occupation by The 2015 target has already been exceeded, with 1085 squares showing signs of occupation in either the main survey or alternate squares spot-checks. The recovery has thus proceeded at a slightly faster rate than expected in 2006 but is still close to, or slightly below the expected recovery curve published by Strachan and Jefferies (1996). The continued recovery has brought an increase in the number of reported otter road kills. These have nearly doubled from 313 reported deaths on the road during the four year period 2002 to 2005 to 600 in the four year period 2006 to These and other dead otters reported to the Environment Agency form the basis of the programme of otter post mortem and tissue analysis undertaken with Cardiff University and the Centre for Ecology and Hydrology. This work has shown that the current suite of chemicals monitored in otter tissue has declined to levels where they should not cause significant pathology. One of the results of the recovery of otter populations has been increased concern about predation, particularly on still water fisheries and on specimen fish. This creates a challenge to all those involved in river, wetland and fishery management to ensure that the successful return of our top freshwater predator is not seen as a problem for fisheries interests.

5 Contents Summary Contents page Introduction Methods Overall results for England Map 1 Alternate 50km squares used in survey Table 1 results for survey by region and comparison with other surveys Table 2 Summary of Results by 50km square Fig 1 Change in percentage of positive sites by region Maps 2-6 Percentage positive by region ( to ) Maps 7-11 Positive/new positive ( to ) Map 12 Otter distribution by 10km square Map 13 Catchment (Leap) areas in England The regional reports introduction (Regional reports each with maps) North West Northumbrian Yorkshire Dee Severn Trent Wye Anglian Thames South West Wessex Southern Mink Map 14 Mink distribution Map 15 Mink distribution Map 16 Mink distribution by 10km square Otter sightings - PTES Discussion Otters and fisheries Conclusions Priorities for future action Funding Acknowledgements References Appendix 1 Typical site map Appendix 2 Section of spreadsheet Appendix 3 Alternate squares recording sheet

6 1.0 Introduction The Eurasian or European otter (Lutra lutra) is widely recognised as an emblem for nature conservation in the UK because it is a top predator and important biological indicator of the health of our rivers and wetlands. Monitoring the status of the otter therefore gives us a valuable measure of the state of our water and wetland ecosystems. In England it is a largely nocturnal animal and is rarely observed in the wild. It is however possible to detect its presence by searching for faeces (spraints) and footprints. The otter suffered serious declines throughout most of its European range, and by the mid 1970s the UK otter population had been reduced to a point where they only existed in Scotland, parts of Wales and the West Country with a few remnant populations in other parts of England. Conservation action for the otter in Britain has a long history with many players fulfilling different roles. The Environment Agency is now the contact point for otter conservation under the UK Biodiversity Action Plan (UK BAP) and is a lead partner with the Wildlife Trusts in implementing the Otter Species Action Plan. The Otter BAP Steering Group also includes representatives from the statutory nature conservation bodies Natural England (NE), Countryside Council for Wales (CCW), Scottish Natural Heritage (SNH), the Northern Ireland Environment Agency and the Joint Nature Conservation Committee (JNCC) as well as Water UK (umbrella body for the water companies), the Scottish Environment Protection Agency (SEPA), the Environment and Heritage Service of Northern Ireland, the Department of Agriculture (N.I.) and the Wildlife Trusts. The first national otter survey of England was carried out in (Lenton et al., 1980). It provided a baseline for the distribution of otters and, together with surveys in Wales, Scotland and Ireland (Crawford et al., 1979; Green & Green, 1980; Chapman & Chapman, 1982), was undertaken in response to growing concern for the status of the otter in Britain (O Connor et al., 1977). Of the 2,940 sites surveyed in England in , only 170 (5.8%) showed evidence of otters. This confirmed the results of the analysis of hunting records (Anon, 1969, 1974; Chanin & Jefferies, 1978), the impression of many naturalists (Walker, 1970, Howes, 1976, Lloyd, 1962) and the results of a volunteer survey by the Mammal Society (O Connor et al., 1977) that there had been a major decline in otter distribution. The baseline survey showed that the only significant populations of otters remaining in England were in the south west and along the Welsh border, with small and fragmented populations in East Anglia and in northern England. Otters were absent or only sparsely distributed in much of lowland and central England. Subsequent surveys and research have demonstrated that this was probably the nadir of the decline which began in the late 1950s, and was primarily caused by the introduction of the persistent organochlorine pesticides dieldrin and aldrin (Strachan & Jefferies 1996). National surveys were repeated in (Strachan et al., 1990), (Strachan & Jefferies, 1996) and (Crawford, 2003) using the same method and visiting the same sites. A further 249 sites were added during the survey to improve coverage bringing the total to Of these 284 (8.9%) were positive in and 706 (22.1%) were positive in A further addition of 238 sites was made for the survey bringing the total to 3327 sites. Of these 1137 (34.2%) were positive. In the survey 1874 (56.3%) were positive. These surveys plus a large amount of monitoring effort by the Vincent Wildlife Trust, staff from the Wildlife Trusts and the Environment Agency and by other groups and individuals showed that otter populations were gradually recovering. This recovery however has been markedly slower than that for many raptor species such as the peregrine falcon which were similarly affected by organochlorine compounds. This may reflect the slower breeding rate and recovery potential of otters but a number of other factors may have slowed the rate of recovery of the otter. These include serious continued persecution, particularly hunting, up

7 to 1977 (when the otter was given full protection in England and Wales), poor water quality, particularly the impact of toxic compounds such as polychlorinated biphenyls (PCBs), increased levels of traffic leading to an increase in road deaths (Strachan & Jefferies, 1996; Bradshaw, 2002; Chadwick, 2007) and possibly increased human disturbance. River and wetland habitat loss and degradation may also have played a part particularly through its impact on fish stocks. In addition otters are restricted to terrestrial habitats (including rivers and streams) which must slow their ability to re-colonise areas remote from remnant populations unlike the bird species similarly affected by organochlorine pesticides. Continued monitoring is essential for assessing the rate of recovery, a fact recognised as far back as 1979 when it was proposed that a regular cycle of surveys should be undertaken (O Connor et al., 1979). The survey was the fifth in the series and for the first time covered the whole of England. All the 3327 sites surveyed in the fourth survey were re-surveyed and of these 1874 (56.3%) were positive. In addition, for the first time, data was gathered for all those 50km squares not covered in the main survey. It was not possible to survey these to the same level as the main survey so a presence/absence survey by 10km squares was decided upon. Use was made of existing data from Wildlife Trust and Environment Agency surveys, casual records and locations of dead otters reported to the Environment Agency during the period from January 2009 to the end of the survey. All the remaining 10km squares for which there was no existing data were surveyed by carrying out up to 10 spotchecks per 10km square. These were carried out by the author, the contract surveyors, experienced staff from the Environment Agency and Wildlife Trusts and trained individual volunteers. The final squares were surveyed in March Squares were considered negative if no signs could be found at 10 spot-checks. Otter signs were found in 552 of the km squares spot-check surveyed as part of the alternate squares survey. The main part of the survey was carried out by five experienced surveyors with the remainder filled by the author and one other experienced surveyor. This enabled the whole survey to be carried out between 20 July 2009 and 20 February 2010, a period of exactly seven months. The alternate squares spot-check work was started in October 2009 and completed by the end of March The otter is one of over 400 species in the UK for which a species action plan has been produced (HMSO, 1995). The otter was considered a priority species for conservation action because of its earlier decline. It was therefore recognised that co-ordinated action and monitoring were required to ensure the restoration of a fully viable population throughout its historic range across the UK. The otter has one of the highest levels of protection for a species under European and UK law, but this alone does not guarantee its recovery.

8 2.0 Methods In the survey two survey methods were used in order to give both continuity of data and a comprehensive survey of the whole of England. The main survey followed the standard otter survey methodology used in all previous England surveys, covering the same sites as before, while spot-check surveys were used for the alternate squares to give coverage of previously unsurveyed 50km squares. 2.1 Main survey Method The standard otter survey method was used following that used by Lenton et al., (1980). At each site a 600m survey was carried out along one bank by searching for otter signs, usually 300m upstream and downstream of a bridge or other access point. For the first national survey in surveys were halted as soon as otter signs were found so the full 600m length was only surveyed at sites where no signs were found. For the second ( ) and third ( ) surveys a full 600m was usually surveyed at each site even if otter signs were found before this. The and surveys reverted to the methodology to reduce survey time Survey sites These were originally selected in at approximately 5-8km intervals along main rivers and coast or lake shore with additional surveys included to ensure that a wide range of aquatic habitats were represented (Lenton et al., 1980). Less than half of England could be covered by one surveyor in two years so only alternate 50km squares, the north-west and south-east quarters of each 100km square of the National Grid, were surveyed to give geographically representative cover of all regions. A total of 2940 sites was surveyed in twenty eight 50km squares and partial squares. Due to time constraints during the first national survey three of the allocated full 50km squares were not surveyed. These were; TQ n/w (which covers central London), because there was little chance of otter presence; TL s/e, which had been surveyed a few months before as part of a county survey; and SK n/w due to time constraints. Seven of the partial 50km squares next to the coast, some of them very small, were also left out due to time constraints. During the second national otter survey in a further four squares or partial squares (NZ s/e, SK n/w, TL s/e and TR n/w) were added, bringing the total of squares and partial squares surveyed to 32 and the number of sites surveyed (including assumed negative sites see below) to All these sites were revisited in the survey. For the survey it was decided that all alternate 50km squares would be surveyed, even where they would contain very few sites. A further six previously unsurveyed 50km squares and partial squares were added bringing the total of squares and partial squares surveyed to 38 and the total of sites surveyed to The survey followed the survey sites. In addition for the first time data was gathered for all those alternate 50km squares not covered in the main survey (see 2.2 below) Surveyors

9 The main survey was carried out by five highly experienced otter surveyors with the author and one other surveyor completing any gaps. This allowed the survey to be completed in seven months compared to over two years for all the previous surveys of England. In the alternate squares, those 10km squares, for which prior information was not available, were spot-check surveyed between October 2009 and March Data recording (main survey) In the first four surveys, recording was done using a standard recording sheet developed in 1977 (Lenton et al., 1980). These remained largely unaltered through to the survey. Sheets were filled in by hand in the field and included a description of the reach walked or a sketch map both of which were sometimes difficult to interpret. It was therefore not always easy in the field to determine when 600m had been completed or whether exactly the same reach and bank had been surveyed. With the development of Geographical Information System (GIS) mapping, hand held Global Positioning System (GPS) equipment and modern computer equipment, quicker survey recording could be developed and more accurate grid references produced. For the survey each site was located on a GIS mapping system and, using the sketch maps from previous surveys, the exact reach previously surveyed was identified. A map of each site was then printed with the start point indicated and a red line, measured on the map at exactly 600m, indicating the exact reach and bank to be surveyed (see appendix 1). These were provided to the surveyors for use in the field. Recording was done in the field using a laptop computer, directly onto a spreadsheet with one line for each site (see Appendix 2) The spreadsheet was already filled in with the basic site information for each site (Site No., Site Name and (nominal) Start Grid Reference). The opportunity was taken to correct any errors in the start grid reference by locating each start point with a hand held GPS. Any spraint sites located were also accurately located with GPS. Photos were taken at the start point and of each spraint site Timing of the surveys In some of the previous surveys attempts were made to carry out surveys at roughly the same time of year as earlier surveys. However the spread of dates for the four previous surveys made this less realistic for the survey and it was therefore not attempted. Since the method is robust the number and distribution of positive sites should not be affected. The distance surveyed and the number of spraints located may differ but these do not influence the results. Comparison of different regions surveyed at different times of year has been a feature of all the previous surveys Non-visited and assumed negative sites Non-visited sites (assumed to be negative) were introduced in the survey, mainly for those rivers located in large conurbations such as Birmingham. It was assumed that otters would not enter urban areas so these rivers were not surveyed because results were almost certain to be negative. If non-visited sites were excluded from the analysis the proportion of positive sites in a mainly urban square would be highly skewed and would bias the conclusions. In some cases access to a site was refused and an alternative was not available. Survey sheets were filled in for these sites which were categorised as assumed negative. In there were 204 such sites. The number was 136 in and 83 in In and all survey sites were visited and only those where permission was refused or with serious access difficulties were recorded as assumed negative. There were 12 of these in and 13 in

10 2.1.7 Spot-checks In the survey spot-checks, generally at bridges, were used as a quick way to add to the available knowledge of otter distribution. They were considered particularly useful where there were no positive sites in a catchment and bridges could be easily and quickly checked. In these cases casual records of this sort added greatly to the available knowledge. With the complete coverage of main survey 50km squares in the and surveys they were not considered a necessary part of the main survey. Spotchecks were therefore not used during the main survey but were used in the alternate squares Distance to first spraint For each main survey site the distance surveyed, that is the distance to the first otter signs, was recorded. Of the 1874 positive sites, otter signs were found within 10m of the start point at 888 (47.4%). This coincides with the data from the Otter Survey of Wales. In that survey 89/179 (49.7%) of positive sites were recorded as being within 10m of the start point (A. Crawford, unpublished data). Unfortunately similar data is not available for other surveys. Alternate square surveys Method In order to have a robust data set to report against national BAP targets, data from the 50km squares not previously surveyed was required. It was not possible to carry out full surveys at a comparable level to the main survey so a presence/absence survey by 10km squares was decided upon. For some squares there was existing data from Environment Agency surveys, Wildlife Trust surveys, casual records and locations of dead otters reported to the Environment Agency. This existing data covered the period from January 2009 onwards Survey sites All the remaining squares were surveyed by carrying out spot-checks. Spot-check sites were chosen by the surveyors from maps or using local knowledge. Usually a maximum of 10 spot-checks were carried out in each 10km square but in exceptional cases such as partial squares on the coast or highly urbanised areas a smaller number were carried out. Spot-checks in each 10km square ceased when the first signs of otters were found. Squares were considered negative if no signs could be found at any of the 10 spot-checks and there was no data from other sources showing otter presence within the survey period. Survey work on the alternate squares started in October 2009 and the final squares were completed in March Surveyors Alternate squares spot-checks were carried out by the author, the contract surveyors, experienced surveyors from the Environment Agency and Wildlife Trusts and experienced individual volunteers. A very large number of individuals gave their time to do this work Data recording (alternate squares)

11 Because of the large number of contributors to the alternate squares survey recording was done on a standard form (Appendix 3). For those squares with existing data from Wildlife Trust or Environment Agency surveys, casual records or locations of dead otters the form was filled in by the author. 2.3 Mink Mink (Neovison vison) signs were also recorded while surveying for otter signs on both the main survey and the alternate squares spot-checks. In both cases the survey was halted as soon as the first otter sign was discovered so the results for mink cannot be considered as a full survey of the occurrence of this species. However the survey does give a minimum distribution for mink. 3.0 Results 3.1 Overall results for England The main survey results for the fifth otter survey of England and the results for each of the regions are summarised in Table 1. Results for each 50km square are summarised in Table 2. The results for the baseline survey and subsequent surveys are listed in the same tables. A total of 2940 sites was surveyed in This was increased to 3189 in and 3327 in In the same 3327 sites were surveyed. The number was increased in order to improve coverage but when comparing the percentage of positive sites with the baseline, only those sites which were surveyed in every survey can be used. Of the 2940 sites surveyed in , 170 (6%) were positive. The number of the same sites which were positive had increased to 282 (10%) in , to 687 (23%) in , to 1066 (36%) in and 1726 (59%) in Of the 3327 sites surveyed in , 1137 (34%) were positive and in (56%) were positive. Otter signs were found in 36 of the 38 50km squares or partial squares surveyed in the main survey. Only in squares TQ s/e and TR n/w, both in Southern Region, were no signs found. In TR n/w no signs were found during either the or the surveys while in TQ s/e, signs were found in but not in Otter signs were found in 533 of the km squares in the main survey. In the alternate squares spot-check survey signs of otters were found in 36 of the 39 50km squares or partial squares surveyed. Some of the partial 50km squares were very small, one of these (TV n/e) consisting of only part of one 10km square. Otter signs were found in 552 of the km squares included in the alternate squares survey. Of the total of km squares in England (a figure that excludes some partial coastal squares but includes some squares largely in Wales or Scotland), otter signs were found in 1085 (76.3%).

12 Map 1

13 Table 1 Results of the main survey by region and comparison with previous surveys Region positive/total positive/total positive/total North West 9/332 (2.8%) 31/322 (9.6%) 31/331 (9.4%) Northumbria 14/169 (8.3%) 17/169 (10.1%) 17/174 (9.8%) Yorkshire 4/227 (1.8%) 5/227 (2.2%) 6/270 (2.2%) positive/total positive/total /322 (28.9%) 93/331 (28.1%) 45/169 (26.6%) 46/174 (26.4%) 25/227 (11.0%) 28/270 (10.4%) positive/total positive/total /322 (34.2%) 110/371 (29.6%) 85/169 (50.3%) 90/174 (51.7%) 44/227 (19.4%) 68/284 (23.9%) positive/total positive/total /322 (58.1%) 195/371 (52.6%) 135/169 (79.9%) 140/174 (80.4%) 144/227 (63.4%) 179/284 (63.0%) Dee 0/12 (0.0%) 1/12 (8.3%) 5/12 (41.7%) 6/12 (50%) 8/12 (75%) Severn 13/328 (4.0%) 22/328 (6.7%) 105/328 (32.0%) 127/328 (38.7%) 194/328 (59.1%) Trent 0/238 (0.0%) 0/238 (0.0%) 0/282 (0.0%) Wye 12/70 (17.1%) Anglian 20/622 (3.2%) 232/70 (32.9%) 8/622 (1.3%) 8/725 (1.1%) Thames 0/169 (0.0%) 0/169 (0.0%) 0/179 (0.0%) South West 91/388 (23.5%) 167/388 (43.0%) 12/238 (5.0%) 18/282 (6.4%) 49/70 (70.0%) 52/622 (8.4%) 58/725 (8.0%) 4/169 (2.4%) 4/179 (2.2%) 259/388 (66.8%) Wessex 2/151 (1.3%) 1/151 (0.7%) 29/151 (19.2%) Southern 5/244 (2.0%) 7/244 (2.9%) 8/279 (2.9%) Totals 170/2940 (6 %) 282/2940 (10%) 284/3189 (9%) 9/244 (3.7%) 12/279 (4.3%) 687/2940 (23%) 706/3189 (22%) 58/238 (24.4%) 58/282 (20.6%) 92/238 (38.7%) 98/282 (34.8%) 58/70 (82.9%) 58/70 (82.9%) 166/622 (26.7%) 188/728 (25.8%) 13/169 (7.7%) 18/225 (8.0%) 322/388 (83.0%) 332/399 (83.2%) 64/151 (42.4%) 69/172 (40.1%) 13/244 (5.3%) 13/282 (4.6%) 1066/2940 (36%) 1137/3327 (34%) 350/622 (56.3%) 414/728 (56.9%) 89/169 (52.7%) 92/225 (40.9%) 331/388 (85.3%) 341/399 (84.5%) 115/151 (76.2%) 132/172 (76.7%) 23/244 (9.4%) 23/282 (8.5%) 1726/2940 (59%) 1874/3327 (56%)

14 50km Square Survey Survey Survey Survey Survey Positives /Total % Positive Positives /Total % Positive Positives /Total % Positive Positives /Total % Positive Positives /Total % Positive NT s/e 1/ % 1/ % 19/ % 36/ % 37/ % NX s/e 0/0 0.00% 0/0 0.00% 0/0 0.00% 0/5 0.00% 4/ % NY n/w 3/ % 7/ % 31/ % 40/ % 47/ % NY s/e 3/ % 7/ / % 48/ % 88/ % NZ n/w 13/ % 14/75* /75* 30.67% 42/75* 56.00% 62/75* 82.67% NZ s/e 0/0 0.00% 1/ % 4/ % 25/ % 26/ % SD n/w 3/ % 19/ % 36/ % 24/ % 62/ % SD s/e 0/ % 0/ % 6/ % 2/ % 18/ % SE n/w 4/ % 3/ % 13/ % 31/ % 100/ % SE s/e 0/ % 2/ % 13/ % 21/ % 52/ % SJ n/w 0/ % 1/ % 5/ % 4/ % 8/ % SJ s/e 0/ % 1/ % 44/ % 71/ % 93/ % SK n/w 0/0 0.00% 0/ % 6/ % 0/ % 11/ % SK s/e 0/ % 0/ % 3/ % 33/ % 73/ % SO n/w 25/ % 38/ % 70/ % 80/ % 84/ % SO s/e 0/ % 6/ % 49/ % 55/ % 90/ % SP n/w 0/ % 0/ % 4/ % 19/ / % SP s/e 0/ % 0/ % 2/ % 4/ % 70/ %

15 50km Square Survey Survey Survey Survey Survey Positives /Total % Positive Positives /Total % Positive Positives /Total % Positive Positives /Total % Positive Positives /Total % Positive SS s/e 44/182* 24.18% 86/182* 42.25% 140/182* 76.92% 167/182* 91.76% 175/182* 96.15% ST n/w 0/0 0.00% 0/0 0.00% 0/0 0.00% 5/ % 17/ % ST s/e 2/ % 1/ % 16/ % 34/ % 74/ % SU n/w 0/93* 0.00% 0/93* 0.00% 2/93* 2.15% 12/93* 12.90% 57/93* 61.29% SU s/e 4/ % 5/ % 6/ % 8/ % 23/ % SW s/e 6/ % 10/ % 26/ % 48/ % 41/ % SX n/w 41/130* 31.54% 70/130* 53.85% 95/130* 73.08% 101/ % 105/130* 80.77% SX s/e 0/0 0.00% 0/0 0.00% 0/0 0.00% 10/ % 10/ % SY n/w 0/ % 2/ % 8/ % 26/ % 32/ % SZ n/w 1/ % 0/ % 3/ % 11/ % 15/ % TA n/w 0/0 0.00% 0/0 0.00% 0/0 0.00% 4/ % 10/ % TF n/w 1/ % 0/ % 2/ % 43/ % 84/ % TF s/e 16/ % 1/ % 7/ % 17/ % 57/ % TG s/e 0/0 0.00% 0/0 0.00% 0/0 0.00% 1/ % 1/ % TL n/w 2/ % 4/ % 15/ % 36/ % 61/ % TL s/e 0/0 0.00% 0/ % 6/ % 24/ % 63/ % TM n/w 0/ % 3/ % 27/ % 49/ % 80/ % TQ n/w 0/0 0.00% 0/0 0.00% 0/0 0.00% 2/ % 3/ % TQ s/e 0/ % 2/ % 3/ % 4/ % 0/ % TR n/w 0/0 0.00% 1/ % 3/ % 0/ % 0/ %

16 percentage of sites positive Change in percentage of positive sites for otters by region Dee Trent Wye North West Northumbria Yorkshire Severn Anglian Thames South West Wessex Southern Figure 1

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24 Map 9

25 Map 10

26 Map 11

27 Map 12

28 Map 13

29 4.0 The regional reports The reports of the first three Otter Surveys of England (Lenton et al., 1980, Strachan et al., 1990, Strachan and Jefferies, 1996) presented results by Water Authority or National Rivers Authority (NRA) region. For the survey, Midlands Region was split into the Severn and Trent catchments and the Wye and Dee catchments reported separately. The present survey follows the pattern of the survey. For each region the report contains A list of the 50km squares that lie within that region with the number of sites surveyed in the main survey shown in brackets. This number refers only to those sites that lie within both that square and the region concerned. A brief description of the region and notes on the water quality and fisheries where these might impact on otters. A comparison of the results for the suite of sites selected for the survey (which have been surveyed on all subsequent surveys) and, where survey sites were added during subsequent surveys, the results for the total number of sites surveyed during each survey. A summary of the results from the alternate squares survey giving the number of 10km squares covered through spot-checks (where these lie in whole or part within that region) by 50km square. Where otter signs were found within a 10km square that overlaps two regions this is included as a positive square in both the regional reports. In such cases the positive site will only be shown on the map for the region in which the positive site was found. The number of positive squares will therefore be higher in one region than the number of positive symbols on the region/catchment map. A summary of the results for each catchment or subcatchment and comparison with previous survey results. The catchments and subcatchments used follow the Local Environment Agency Plan (LEAP) areas used in the fourth survey report. The catchment name is followed by a number - these refer to the key on the sub-catchment map. The boundaries and numbers are also shown on the region/catchment maps. In many cases only part of a catchment area was included in the main survey where the remainder lies within an alternate 50km square and in some cases no main survey sites were surveyed in a particular catchment where these lie totally outside the 50km squares of the main survey. In these cases the catchment is listed and the data from the alternate squares spot-checks noted. A discussion of the results for the region.

30 4.1 North West Region Surveys were carried out in the following 50km squares NX s/e (5), NY n/w (57), NY s/e (56), SD n/w (108), SD s/e (104), SJ n/w (14), SJ s/e (18), SK n/w (9) Description of region The rivers of the North West exhibit a wide range of riverine types from the short upland rivers of the Lake District and the large, fairly natural river systems of the Eden and Lune to the heavily modified rivers of Greater Manchester, Liverpool and lowland Cheshire. The River Eden and tributaries and the Derwent and Bassenthwaite have been notified as Special Areas of Conservation, with otters as listed features. There is an extensive canal network particularly concentrated in Lancashire and Cheshire. Human activity is mainly centred on the large conurbations, with Manchester, Warrington and Liverpool forming an urban chain across the whole region. Other major settlements include the cities of Preston and Carlisle, while the populations of some areas, such as Cumbria, are increased considerably by tourists during the summer months. Outside the industrial centres, upland sheep farming or lowland dairy farming dominate the region s landscape while coniferous plantations are mainly concentrated in Cumbria. Water quality The large variation of river types and level of human influence in the region gives rise to a wide variation in river quality, from the heavily urbanised rivers of the Manchester and Liverpool conurbations to the very clean rivers of Cumbria. Water quality has improved markedly in the industrial areas in recent years with good fish stocks on the lower Mersey and the Irwell for the first time since the early 20 th century. Fisheries The Border Esk, Eden and Lune catchments support the principal salmon and sea trout fisheries of the region but there are salmon runs on several of the smaller rivers such as the Wyre. The fisheries on many of the central and southern rivers of the region have largely recovered from previous industrial pollution and support good populations of coarse fish as well as the return of salmon and sea trout. Good coarse fisheries can also be found on the Weaver, Dane, Gowy and Bollin.

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32 Results for survey and comparison with previous surveys A total of 371 sites was surveyed in the main survey. Positive sites/total sites - all sites 9/322 31/322 31/331 93/322 93/ / / / /371 % Positive sites - all sites 2.8% 9.6% 9.4% 28.9% 28.1% 34.2% 29.6% 58.1% 52.6% Spot-checks were carried out in an additional 88 whole or partial 10km squares. Alternate 50km Square NY s/w NY n/e SD s/w SD n/e SE s/w SJ n/e Positive/total 10km squares 25/25 7/7 7/12 18/19 0/1 12/24 Summary of results for each catchment Alt Crossens (1) No main surveys were carried out in this catchment but during the alternate squares spotchecks otter signs were found at two widely spaced sites near Kirby and Southport. These are about 38km apart by river and canal but the data is insufficient to determine the true level of otter use in the area. It is more likely that the otter(s) have reached this area from the Ribble catchment to the north rather than by passing through Liverpool. Douglas (2) Positive sites/total 0/0 0/0 0/0 0/15 2/15 Otter signs were found in this catchment for the first time in a national survey, both during the main surveys near Chorley and at one site during the alternate squares spot-checks near Lathom. It is likely that otters reached this area from the Ribble catchment to the north. Lune (3) Positive sites/total 0/18 1/18 3/18 5/18 10/18 The results from the surveys and the alternate squares spot-checks show that otters are now found throughout the catchment. The mix of positive and negative sites in the coastal area around Lancaster indicates that while otters are present there, they are probably still in small numbers in the coastal parts of this catchment. The Lune provides one of the main corridors for the re-colonisation of the area north of the urban area of Manchester/Warrington/Liverpool, particularly the Wyre catchment.

33 Wyre (4) Positive sites/total 0/15 0/15 1/15 0/15 1/15 The results from the surveys and alternate squares spot-checks show that otters are widely but probably very thinly distributed in this catchment. There is likely to be consolidation of this population in the near future. Ribble (5) Positive sites/total 0/55 0/55 5/55 2/56 13/56 There has been a considerable increase in the occurrence of otter signs in the Ribble catchment since the survey but the more industrialised, south western, part of the catchment shows little or no otter presence as yet. The Ribble provides one of the main corridors for the re-colonisation of the area north of the urban area of Manchester/Warrington/Liverpool. West Cumbria (6) Positive sites/total 0/13 2/13 4/13 1/18 7/18 The surveys and the alternate squares spot-checks show a major increase in otter presence in the West Cumbria catchment. The three yearly surveys carried out by Environment Agency staff indicate that otters have re-colonised this area over many years (Bennet & Butterill, 2010). Eden and Estuary (7) Positive sites/total 6/105 11/105 45/105 75/105 88/105 Otters now use all the rivers in this catchment. The negative sites are mainly in the coastal areas, which are difficult to survey, or in the smaller headwater streams which are probably only used intermittently by otters at present. The catchment was surveyed by Environment Agency staff in 2000, 2004 and 2007 (Ratcliffe, 2008) South Cumbria (8) Positive sites/total 3/82 17/82 13/82 24/82 57/82 Otters are now present throughout this area. There is a group of negative sites around Barrow in Furness and on Walney Island even though this area is known to have been used by otters as an otter was found dead on Walney Island in April 2008 (E. Chadwick pers. comm.). The three yearly surveys carried out by Environment Agency staff indicate that otters have steadily re-colonised this area over many years (Spiby, 2007). Croal and Irwell (9)

34 Positive sites/total 0/2 0/2 0/2 0/14 0/14 No signs of otters were found in this area. Lower Mersey (10) Positive sites/total 0/14 0/14 1/14 0/14 3/14 Three positive sites were found on the Gowy catchment but no signs were found on the Wirral despite positive sites there in 2005 (Gaskin, 2005). Mersey and Bollin (11) No main surveys were carried out in this catchment but otter signs were found on the Bollin during the alternate squares spot-checks. It is assumed that colonisation has been from the Weaver catchment to the south. Otters are known to have been present on the Bollin since at least 1995 (A. Crawford pers. obs.) but appear to have shown little expansion in range in that time. Roch, Irk and Medlock (12) Positive sites/total 0/0 0/0 0/0 0/4 1/4 One positive site was found in this area on the River Roch near Bury. The next nearest positive site to this was about 36km away, by watercourse, on the Calder in Yorkshire Region. However a spot-check survey in May 2010 found otter signs on the Rochdale Canal at the watershed between the Roch and the Calder (Yorkshire) near Summit (A. Crawford pers.obs.). This is between the two sites and approximately 18 km from both. It is quite possible that the positive site on the Roch is from a transient animal which used the Calder, the canal and the Roch to cross the watershed. Sankey and Glaze (13) No main surveys were carried out in this catchment and no otter signs were found during the alternate squares spot-checks. Tame Goyt and Etheroe (14) Positive sites/total 0/0 0/9 0/9 0/12 1/12 Only one main survey site, near Whaley Bridge on the Goyt, was positive and otter signs were found near Marple on the Goyt during the alternate squares spot-checks. Weaver/Dane (15) Positive sites/total 0/18 0/18 3/18 3/18 12/18

35 Otters appear to have colonised this area from the Severn catchment to the south. They are now present on most of the rivers and canals in the southern part of the Weaver catchment around Nantwich. The alternate squares spot-checks show that otters are widely distributed in the rest of the area but probably at a low population level. Otter use of the canals in this area is extensive. Discussion The North West region has shown a major increase in otter range since the last survey in The increase has been particularly impressive in the north where otters appear to have re-colonised all the available rivers and streams even in the uplands. In the four northern catchments (3, 6, 7, 8) of the region 162/223 sites (73%) were positive. Regular surveys by Environment Agency staff since 1998 (Bennett & Butterill, 2010; Ratcliffe, 2008; Spiby, 2007) show that otters have been slowly re-colonising the area since then but it will probably be some time before this part of the region reaches full carrying capacity. The northern part of North West region is one of the few areas in Britain with a regular series of surveys over many years enabling the increase in range to be monitored accurately. This is of particular interest as no introductions have taken place in the region. It is thus one of the few areas where we have both a wholly natural increase in range combined with a series of detailed surveys covering the whole period of re-colonisation. In the central part of the region the increase in range has also been considerable. In the survey only three positive sites were found between Lancaster and the Liverpool, Warrington and Manchester urban area. In the survey there were 21 positive sites in that area mainly in the Ribble catchment but also spreading into the Douglas and Wyre and with an outlier on the River Roch. Otters are now widely distributed on the Ribble and Lune catchments. These rivers provide corridors for re-colonisation of the catchments to the north of the urban area of Liverpool, Warrington and Manchester and re-colonisation of the area would be expected in the next few years. The outlying site on the River Roch is 36km from the next nearest positive site, on the Calder in Yorkshire, but a spot-check survey in May 2010 found otter signs on the Rochdale Canal at the watershed between the Roch and the Calder near Summit (A. Crawford, pers.obs.). This is between the two sites and approximately 18 km from both. It is quite possible the positive site on the Roch was a result of a transient animal which used the Calder, the canal and the Roch to cross the watershed. If otters are indeed crossing the Pennines from the Calder catchment to the Roch, then the re-colonisation of this part of North West Region might proceed faster than previously expected. In the report of the survey concern was expressed at the very slow rate of colonisation of the southern part of North West Region. The main surveys and the alternate squares spot-checks show that otters are now widely distributed within the Weaver catchment and appear to have spread from there into adjacent catchments such as the upper Mersey and Goyt. They are now widely distributed south of the urban area of Liverpool, Warrington and Manchester but appear to be present only in small numbers. Initial re-colonisation and consolidation still remains surprisingly slow despite the close connections with the Severn and Dee catchments but it is to be hoped that consolidation of the population will continue. It will be interesting to see if otter populations are able to spread through the urban area and link with the otter population expanding south from Cumbria. 4.2 Northumbrian Region

36 Surveys were carried out in the following 50km squares NT s/e (42), NY s/e (52), NZ n/w (75), NZ s/e (5). Description of region The majority of rivers in this region rise in the northern Pennines or the Cheviots and flow through the coastal plains. Land use is predominantly agriculture with sheep, arable and cattle in order of importance. Forestry also covers a large area, particularly around Kielder reservoir. Open cast mining and its side effects are still apparent in the central parts of the region. Gravel extraction occurs next to a number of rivers, in some cases benefitting the wildlife diversity of the area by the creation of post-extraction wetland habitats. Heavy industry is largely confined to the areas around the mouths of the Rivers Blyth, Tyne, Wear and Tees. However, the region s increased involvement in the service sector has resulted in large-scale redevelopment along many of the region s former industrial riverbanks. A serious problem in the rural parts of the region is riverbank overgrazing and poaching by cattle and sheep causing habitat degradation and silt pollution of watercourses. This has been exacerbated by high stock density and poor maintenance of riverbank fencing. This region, with the Yorkshire Region, now forms part of the Environment Agency North East Region. Different southern boundaries of the region have been used in the reports of past surveys. In this survey, as in the survey, Northumbrian Region is taken to include the Kilton Beck but not the Easington Beck. Water quality There have been major improvements in water quality in the region but intermittent pollution incidents still occur on some rivers, and storm-water overflows and farm run off cause localised problems. Acidification is still an issue on the upper reaches of many rivers, a problem exacerbated by large scale conifer forests in some catchments. Fisheries Most of the region s rivers are predominantly game fisheries with runs of migratory salmonids and stocks of brown trout, often supplemented by stocking. The Tyne, Wear and Tees support good populations of mixed coarse fish, mainly dace, chub and roach and the Tweed and Till in the north support smaller populations of these species. There are numerous stillwater fisheries with both game and coarse fish. All three species of lamprey have been recorded and eels, although declining, are present throughout the region. Many of the smaller tributary streams and coastal burns have reduced fish populations as a legacy of past pollution.

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38 Results for survey and comparison with previous surveys A total of 174 sites was surveyed in the main survey. Positive sites/total sites - all sites 14/169 17/169 17/174 45/169 46/174 85/169 90/ / /174 % Positive sites - all sites 8.28% 10.06% 9.77% 26.62% 26.44% 50.30% 51.72% 79.88% 80.46% Spot-checks were carried out in an additional 61 whole or partial 10km squares. Alternate 50km Square NT n/e NU s/w NY n/e NZ s/w Positive/total 10km squares 1/1 13/14 20/21 25/25 Summary of results for each catchment Cheviot/East Northumberland (16) Positive sites/total 13/86 14/86 33/86 63/86 79/86 The surveys and the alternate squares spot-checks show that otters in this area now use all the available watercourses, even small coastal streams like the Embleton Burn, and the coast. The very small number of negative sites in the area are either on very small streams such as the Portland Burn or at coastal sites which were difficult to survey adequately. Tyne (17) Positive sites/total 0/39 1/39 9/39 17/39 26/39 The surveys and the alternate squares spot-checks show that otters have now re-colonised most of the available watercourses. The small number of negative sites in the catchment are on very small streams or at coastal sites which were impossible to survey, and were thus assumed to be negative, or those which were very difficult to survey adequately. The upper part of the catchment was only surveyed as part of the alternate squares spot-checks but these show that otters are present on all the major watercourses and at least some minor streams. Wear (18) Positive sites/total 0/15 0/15 0/15 3/15 8/15 The surveys and the alternate squares spot-checks show that the otter population in the catchment has now expanded to re-occupy all the available watercourses. The small number of negative sites are either on very small streams or at sites at which access was refused and were thus assumed to be negative. An alternate squares spot-check on the Hawthorne Burn and local surveys (T. Coult, pers. comm.) show that otters are now using some of the small coastal streams or denes where cover is good but fish stocks are small. It seems likely that otters are accessing these from the sea and probably finding prey on the coast as well. Tees (19)