A DNA-based survey of otters in Sheffield

Peeky otter

We are appealing for funds, sponsors and partners to continue our DNA study of Sheffield's otters, if you can help please visit our fundraising page or contact Dr Deborah Dawson (d.a.dawson@sheffield.ac.uk)

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The Eurasian otter (Lutra lutra) underwent a severe decline in the UK due to pollution caused by chemical pesticides, habitat loss and persecution, becoming locally extinct in much of England. Bans on pesticides, legal protection provided by the Wildlife and Countryside Act (1981), improvements in water quality and targeted conservation effort have led to the return of the otter to many counties, including Yorkshire and Derbyshire. Otter recovery has been slow, especially in the North of England. Otter numbers have been estimated on spraint abundance which suggested a current very rough estimate of 1600 otters in England (Source: PTES).

 

Little is known about the UKs recovering population of otters and further research is needed. As far as we are aware ours is the first DNA-based survey of otter numbers in the North of England.

Media reports about this project:

BBC News - DNA survey monitors health of Sheffield's urban otters

Radio Sheffield - Kat Cowan Saturday morning show, 23rd September 2017 (Sound clip)

     

AIMS

i)  identify the number and sexes of otters on the River Don surrounding Sheffield.

ii)  investigate the localities and distribution of otters in Sheffield.

iii)  reveal territory ranges and any landscape barriers.

   

The data obtained will be used to provide information to those responsible for river and riverside planning applications and conservation management strategies. It will allow us to document future changes in the number of otters along the River Don.

  

METHODS

a)  The banks of the River Don from Deepcar to Rotherham (24 km), including Sheffield city centre, were searched and over 100 spraint (faecal) samples collected. The majority of samples were collected during Summer 2016 and Spring 2017.

b)  Genomic DNA was extracted from the faecal samples using commercial kits.

c)  The DNA obtained from the sample was PCR amplified with an otter-specific genetic marker in order to identify if it was produced by an otter or not. (The invasive American mink, Neovison vison is present on the River Don and published DNA studies have revealed mink scat being mistaken as otter spraint.)

d)  A genetic sex marker was used to identify the sex of the otter producing each spraint.

e) A set of 7 newly designed microsatellite markers were used to genotype the samples (in triplicate) to obtain a DNA profile from each of the otter spraint samples.

f)  The microsatellite DNA profiles obtained for each sample were compared to identify how many unique DNA profiles exist (and so how many different otters (of each sex) are present).

DNA extraction, sequencing, microsatellite genotyping and sex-typing was performed at the Molecular Ecology Laboratory, in the Department of Animal and Plant Sciences at the University of Sheffield.

 

RESULTS

1. Otters were detected in urban, suburban and rural locations on the River Don.

2. Seven otters were detected in the urban-suburban areas of Sheffield, including at least two males (samples collected in 2017).

3. A female otter was detected in a more rural location north of Sheffield (sample collected in 2016).

4. More male spraint was found than female, which might suggest that either more males are present (during the sampling time) or that male otters spraint more than females. Otters are believed to spraint upto 20 times per day.

5. Otter and the invasive American mink Neovison vison were both present at two locations on the River Don.

 

Future Work (subject to further funding)

We hope to continue this work to obtain a DNA profile for the female otter identified on the outskirts of Sheffield to investigate if any of the other otters found closer to the city may be her grown-up cubs (click here for sounds of otter cubs).

We are appealing for funds, sponsors and partners to continue our DNA study of Sheffield's otters, if you can help please visit our fundraising page or contact Dr Deborah Dawson (d.a.dawson@sheffield.ac.uk)

    

Collaborators

This work on the River Don's otters was done in collaboration with The Sheffield and Rotherham Wildlife Trust and Dr Hannah Dugdale at the University of Leeds.

   

Acknowedegements

We thank Jason Palmer, Kirsty Lee, Alicia Bailey and the keepers (and the otters) at The Chestnut Centre, Otter, Owl and Wildlife Park and New Forest Wildlife Park for their kind support, sharing knowledge and providing vital control samples for this project. Professor Stuart Piertney at the University of Aberdeen very kindly provided otter DNA extracted from tissue taken from roadkill otters and these were used to assess the markers. We are also grateful to Dave Webb of the UK Wild Otter Trust for providing training in finding signs of otters and his generous advice and encouragement and permission to use otter images.

Expert advice was vital to this study. Andrew Crawford of the Environment Agency kindly shared his vast knowledge on the historical otter population crash, surveying top-tips and key insights into otter behaviour. Chris Firth MBE of the Don Catchment Rivers Trust shared local knowledge of the River Don, its industrial past, barriers to wildlife connectivity and knowledge of local fish and Jack Perks kindly advised on the life history of British freshwater fish and shared knowledge of local otters and wildlife, as filmed for the Derbyshire Wildlife Trust. The Don Network also offered support by providing grants for the camera traps used in monitoring for the Wildlife Trust's Otterly Amazing project. Last but not least, Christine Gregory kindly shared her wealth of knowledge of water voles, mink and otters and allowed use of her beautiful images of local wildlife to enhance presentations of our work. 

  

Click here to see more details of our many kind collaborators and supporters.

  

Sample Collection Team

The River Don was surveyed and spraints kindly collected by a team of 34 volunteers including members of the general public, members of the Wildlife Trust, staff and students of The University of Sheffield and members of the Sheffield Canoe Club.
Volunteers were trained by Dave Webb of the UK Wild Otter Trust and Dr Nicky Rivers, Lizzie McBride, Sara Blackburn and Paul Richards of The Sheffield and Rotherham Wildlife Trust, who also collected spraints.

    

   The Sheffield Otter DNA Team 

Principal Investigator: Dr Deborah Dawson (d.a.dawson@sheffield.ac.uk, @ddawson777)

Identifying individual otters via DNA genotyping with microsatellite markers:

Amy Withers (MSc student, University of Leeds, 2017)
(Amy was jointly supervised by Dr Hannah Dugdale, University of Leeds)
Dr Natalie dos Remedios (2016-2018)
Gracie Adams (Undergraduate Summer volunteer, University of Sheffield, 2016 & 2017)


Otter (copyright Wild Otter Trust)