The Urban Otter

The banks of our own lovely Lee are not just a pretty place for a walk, the Lee is an important place for the otter, often described as our most charismatic but elusive species. It may come as a surprise to some that these wild mammals often go by unnoticed in a busy city like Cork, but as otters are highly secretive animals, they do their best to avoid being seen. They often fish early in the morning or late in the evening when they are less likely to be spotted. The sharper, or perhaps luckier amongst us have on occasion spotted otters near the bus station at Parnell Place and along the quays in the city centre.

An otter photographed by  Brendan Fennessey

An otter photographed by Brendan Fennessy

One of the easiest ways to spot evidence of an otter is to track their faeces (spraints) and these can be used to provide information about their presence. The Distillery fields, North Gate Bridge, University College Cork, is the home to the School of Biological, Environmental and Earth Science, and it is here that urban otter studies have been the topic of short research projects. The first of these studies was conducted by Sleeman and Moore in 2005, and the presence of otters was recorded throughout the city.

A  new pilot study led by Shane White, and other researchers from the Irish Wildlife Trust, University College Cork, and the Mammals in a Sustainable Environment (MISE) Project (part funded by European Regional Development Fund under the INTERREG IVA Programme) based at Waterford Institute of Technology (WIT), collaborated in an attempt to obtain a  better understanding of the urban otter. The Irish Wildlife Trust engaged with members of the general public and held a number of workshops and events at Fota Wildlife Park where volunteers were trained how to record signs of otter activity. Over the course of the investigation that ran from October 2011 to May 2012, 199 potential otter spraints were collected by teams of ‘citizen scientists’ across the city. Using a recently developed genetic toolbox, (work led by David O’Neill of MISE at WIT and published in Molecular Ecology Resources), it was possible to genetically identify 187 of those spraints as otter, and from that, 42 spraints were determined as being from females, and 87 were from males. Finally, the best quality samples were used to obtain a genetic fingerprint, which revealed 11 different otters (six male and five female).

CSI Otter – Who dunnit

Distribution of genetically verified otter spraints  in Cork City (White et al. 2013).

As of yet, there is no indication as to how many resident otters occur within the city or how many otters are transient, i.e. just passing through the river to reach the coastal area. Cork has many tributaries leading into the city, and it is possible that the waterways represent an important route for otters seeking the plentiful food resources available in the sea. Future studies may in time reveal more information about the population dynamics of the urban otter in Cork City, and shed further light into the importance of this urban waterway for the conservation of otters.

The study was a useful insight into citizen science, and to see how scientific studies can successfully engage members of the public. In this case, the success story has been the people who took part. Volunteers gave up their time to participate in this study and showed great enthusiasm to engage with both the Irish Wildlife Trust and the two academic institutes. Not only did the volunteers learn how to spot signs of otters, they learned that their home town is an important habitat for the otter, and through the involvement of the public in studies like this, the information learned by the people will continue to flow through every day conversations. Long after the science has gathered dust, and no longer interests the scientists, the legacy of the Cork otter is with the local community, the very people who need the knowledge in order to sustain the future of the otter.

The study has been published in the International Union for Conservation of Nature (IUCN) Otter Specialist Group (OSG) Bulletin, and is freely available to download. The data from this study is also freely available through the National Biodiversity Data Centre, and will form part of the Mammal Atlas, due to be published in 2015. The Cork Branch of the Irish Wildlife Trust, in conjunction with the volunteers who took part in the study also created an education resource pack, which has been distributed to schools in Cork City.

O’Neill D, Turner P, O’Meara D, Chadwick E, Coffey L, & O’Reilly C (2013). Development of novel real-time TaqMan PCR assays for the species and sex identification of otter (Lutra lutra) and their application to noninvasive genetic monitoring. Molecular Ecology Resources, 13 (5), 877-883 DOI: 10.1111/1755-0998.12141

Sleeman DP, Moore PG (2005). Otters (Lutra lutra) in Cork City The Irish Naturalists’ Journal

White S, O’Neill D, O’Meara DB, Shores C, Harrington AP, O’Reilly C, Weyman G and Sleeman DP (2013). A non-invasive genetic survey of otters (Lutra lutra) in an urban environment: a pilot study with citizen scientists IUCN Otter Specialist Group Bulletin

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