Otter Releases Position Statement 1

Background
The European Otter Lutra lutra population across the UK has recovered over the last 3 decades
and Otters are once again found across most of the country. A rapid decline from the late 1950s
wiped out the population across most of the country, with remnant populations persisting mainly
in the western and northern highlands of England, although the species remained more
widespread in Wales and Scotland.

In Somerset the species had virtually disappeared by 1972 and from the mid 1970s to mid 1980s
only a few individuals persisted on Exmoor. From the late 1980s, we documented a relatively rapid
natural recolonisation of the Otter across Somerset and by the late 1990s the species was once
again distributed across the county. No formal reintroduction was undertaken in Somerset.

At a national level there were reintroduction programmes, primarily those run by the Otter Trust
and these seem to have accelerated recolonisation of the species at a local level, especially in
East Anglia. Exact numbers and release sites are not fully known, and neither is the impact of
these releases on the speed of the recovery of the population. Although, it now seems obvious
that the species would have recolonised the whole country naturally in due course.

The Current Status of the Otter in Somerset
Otters are found across the county in all aquatic habitats. Although, exact numbers are unknown,
the population seems to be stable based on the annual 2 day surveys undertaken by Somerset
Otter Group volunteers. The principal recorded mortality of otters in Somerset is road-killed
animals. SOG has recorded mortality details for over 500 Otters since 1999. Despite a mortality of
28 per year (mean from recent years), the population is apparently stable, indicating that this
mortality is not limiting population. Although we know, neither the size of the population in
Somerset, nor the carry-capacity of the species, there is no reason to think that the two are far
apart. We consider Otters to be at or very near to carrying capacity in Somerset, given the current
habitat and state of the rivers.

Origins of Otter for release
There is no longer a formal Otter captive-breeding programme in the UK, since the Otter Trust’s captive              breeding and reintroduction programme closed down. All otters that are now released are those that have              been rescued and taken into temporary captivity at animal rescue centres. The vast majority of these are cubs.           In some instances these are cubs that have been orphaned after their mother has been killed, but others
are taken into captivity by well-meaning people when they have not been abandoned by the
mother. Rescued cubs are generally kept in captivity for 1 year to 18 months before they are
considered apt for release.

Release or Reintroduction?
It is important to differentiate between a reintroduction programme and releases. Reintroduction
programmes are well-planned integrated projects to repopulate an area where a species has been
extirpated and where the factors that caused its demise have been addressed. The IUCN
Reintroduction Specialist Group has excellent guidance on criteria for such projects. It is clear
that any further releases in the UK can not be considered as reintroductions, as there is already a
natural population of otters across the country and as such any release does not fulfil the IUCN
criteria. Thus, any release can not validly be considered to be a contribution towards the conservation of the Otter in the UK, but is rather an act of animal welfare aimed to benefit the
individual Otter being released.

Potential Issues and Problems when Releasing Otters
There are a number of important considerations to be taken into account when considering
releasing an otter in the UK. These can be grouped according to the potential negative impact
that could occur. It is important to recognise the differences in ecology and behaviour of Otters
compared with our other larger carnivores (Badgers and Foxes). In the main otters live on and
defend large linear territories along rivers. Their primarily nocturnal and aquatic habits, mean that
they defend territories via scent-marking through spraints, but also that when they meet an
intruder they do so at very close range and aggressive fighting is a normal behaviour. They breed
in holts (dens) along waterways and these are usually easily found by other otters. Many roadkilled
otters show significant bite wounds from fighting.

A. Impacts on Wild Otters
I.    Otters that have been in captivity could potentially carry a disease that could impact wild
otters.
II.   Male otters are known to kill cubs that are not their own and could potentially do so after
being released.
III.   Males and females, to a lesser extent, could compete with existing otters for territory, food
or holts.
IV.   Released Otters, especially males, may fight with wild Otters and cause them injury or
even kill them.

B. Welfare of the Released Otter
I.   Otters, especially males, defend territories aggressively and will fight with intruders.
Releasing a young male otter into an established territory of a male may well result in harm
and even death of the released otter.
II.  It is illegal to feed animals in captivity live vertebrate prey. This means captive-raised otters
are not usually as proficient hunters as wild otters.

C. Impacts of River Users and Public Perception
I.   Some fishermen believe that there are continuing releases of otters that are negatively
impacting their fisheries, and some believe “hundreds” of otters are being released. Any
releases can contribute to reinforce this unfounded belief.
II.   Released otters, possibly with a lower aversion to humans, could impact fisheries.

Releasing Otters
There are two main scenarios where one might wish to release a rescued or rehabilitated otter:

1.   An adult or independent sub-adult that has been injured in some way and that has recovered
in a quick period of time (ideally less than a month). In this case we recommend that the otter
be released as soon as possible and as close as possible to the location at which it was
found. This animal should be able to survive on its own and will need no supplementary
feeding etc. and a “hard release” is appropriate. We recommend a full health check, microchipping
and that a reference DNA sample is taken. The risks to wild otters are minimal, if the
period in captivity has been short.

2.   A rescued cub that has been raised in captivity for an extended period of time. This is
considerably more complicated and presents significantly greater risks to wild otters and
welfare issues for the released otter. This release needs more thorough planning and
evaluation of potential impacts. A ‘soft-release’ from a specially constructed temporary
enclosure after a period of familiarisation, and supplementary feeding for a period postrelease,
is recommended.

SOG recommends that prior to a release in Somerset the Otter should be:
1.   Be checked for disease.
2.   Be microchipped with details passed to Somerset Otter Group and Cardiff University Otter
Project.
3.   Have a DNA sample taken and passed to Somerset Otter Group or Cardiff University Otter
Project.

Release Sites
When selecting a potential release site for rescued Otters that have been in captivity for an
extended period it is important to consider the following:
•   The site should be within the same catchment from where the Otter was rescued.
•   No otter should be released within 5 miles of an unfenced commercial fishery.
•   Prior to the release of any male otters, a thorough survey of main river and all tributaries within
2 miles should be undertaken to search for signs of any cubs. If cubs are present, the Otter
should not be released.
•   The release site should be safe, with access to relatively slow-flowing water with good
densities of prey.

Post-release Monitoring
We recommend that trail cameras be installed at and near the release site, ideally both upstream
and downstream of the site. These cameras should be maintained for at least a month.

Conclusions
1.  There is not a conservation justification for releasing Otters in Somerset, or across most of the
UK. Releases are not reintroduction as we understand it from a conservation perspective.
2.  Rescue, rehabilitation and release of otters is an animal welfare action for the benefit of the
individual Otter, rather than the species.
3.  Somerset Otter Group recognises the hard-work of animal welfare groups, such as RSPCA
and Secret World, and appreciates that they wish to see recovered animals returned to the
wild. We share that hope, but also wish to minimise potential negative impacts on wild Otter
populations in Somerset. We also recognise that our shared concern for the conservation of
Otters and the welfare of individuals, creates a dilemma for rescue centres that have otters.
4.  Adult and sub-adult Otters that have only been held briefly in captivity should be released
back to their finding location as quickly as possible.
5.  If cubs are to be released a release plan should be developed and additional steps taken to
ensure that the site is suitable, that risks to wild otters are minimised, and that the chances for
the released otter are maximised.
6.  Transparency about releases is important for monitoring of their effectiveness and impact and
also for public perception.