Nearly 200 signs of otter activity recorded across Dublin’s rivers

Nearly 200 signs of otter activity have been observed around Dublin's rivers and streams over the past two years, new research commissioned by Dublin City Council has found.

The Dublin Otter survey, carried out over two years between 2018 and 2019, found 196 signs of otters across 84km of watercourses including the rivers Mayne, Santry, Naniken, Tolka, Liffey, Camac, Poddle, Dodder, Owendoher, Little Dargle and Slang.

The research was also carried out around the Whitechurch, Wyckham and Elm Park streams.

While otters are shy animals that mainly come out at night and can be difficult to find, their presence can be spotted through a range of signs including spraints (droppings), latrines (regular spraint sites), slides (worn areas where otters enter the water), couches (resting areas) and holts (burrows).

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Otters are a protected species under the EU habitats directive and Ireland is required to monitor and conserve otter populations.

The Dodder and Tolka rivers were found to be the most heavily marked with otter signs while in other areas, such as the Naniken in St Anne’s Park, no otter marks were recorded.

The study found the rivers of Dublin remain “highly important passageways for wildlife and also important breeding areas for otter” proving that otters can “continue to survive in densely populated areas such as Dublin”.

The rivers examined during the study are “some of the last remaining secluded habitats in cities that are becoming increasingly fragmented”.

The authors of the report, Bill Brazier and Ross Macklin, also noted that while its commonly believed otters prefer to stay away from human activity, evidence from their research “isn’t quite that clear cut”.

‘Substantial buffer’

“We did find that the less-disturbed areas of the city’s rivers and streams featured more otter activity in general. Having said that, provided there is some substantial buffer, such as mature tree lines or inaccessible areas bounded by high walls, between the river channel and human disturbance, otters can be found in surprisingly urbanised areas.”

New methods were used in the two-year research project including surveying the introduction of a new index to calculate levels of human disturbance to the otter habitats.

City council senior executive parks and landscape officer Maryann Harris said the results of the study highlighted the need to conserve undisturbed sections of rivers for otters to breed while also reinforcing the council’s goal of the “re-naturalisation of river corridors”.

“Otters are sensitive to encroachment by development and this study will better inform the management and conservation requirements for otter in the city,” she said.