As otter numbers have successfully recovered across the country they are having an impact on fisheries through predation of stock. While otter numbers were low, still water fisheries stocked with large carp became widespread and specimen sized fish a real prospect in our rivers due to improved water quality, habitat and little predation. Now they have returned to most areas, otters are presented with foraging opportunities that come into conflict with angling interests, with numerous examples of expensive or highly prized specimen fish being taken by otters.
The Angling Trust welcomes the Predation Action Group’s publication ‘The Big Picture’ because it is a useful collation of the many reports of damage to fisheries from predation and confirms once again that there is a serious problem with predation, including by otters, on many still water fisheries and some rivers. Otter numbers recovered following the banning of the pesticide DDT and a programme of releasing captive-bred otters in the 1980s and early 1990s. There is no evidence of any releases since 1999.
The Environment Agency published the 5th Otter Survey of England 2009-2010, providing an overview of otter recovery up to that point and an informative document for those interested in how recovery has happened. Please click HERE to read this.
Following two year's work with the Angling Trust, Natural England, fishery owners & anglers, the UK Wild Otter Trust has secured England’s first class licence from Natural England for the live capture & transport of otters Please click HERE to find out more.
The Trust made a call for measures to manage the problem –
The Angling Trust has also set out an action plan to address otter predation, which was agreed with the Predation Action Group in 2014.
Please click HERE to view the Angling Trust Action Plan on Predation (published Feb 2014)
The European Otter (Lutra lutra) is a member of the family known as “Mustelids” and this family includes the Badger, Mink, Weasels, Stoats, Martins and Polecats. Otters are the only true semi-aquatic members of the mustelids family. The European Otter is the only native UK otter species and have been here since the last Ice Age, evolving millions of years ago.
General description -
The European otter can grow up to 1.3 metres in length and can weigh up to 11kg. The male ‘Dog’ otter is larger than the female ‘Bitch’ otter. On average an adult otter will eat between 1-1.5kg of food per day. Their main diet is fish which makes up approximately 75-95 % of the food source, but they will also take birds, mammals, crustaceans and amphibians.
The gestation period is 9 weeks and they can breed at any time of the year, although in the Northern Isles of Scotland this is usually in the spring which tends to coincide with maximum food resources. Generally they have 2 or 3 cubs weighing no more than 40gms which are not born natural swimmers. The young will open their eyes within 5 weeks and will start to leave the natal holt at 10-12 weeks old.
The Otter, despite being a strong swimmer, normally does not stay underwater for a long period, usually no more than 30 seconds at a time when hunting. The cubs will stay with their mother for up to a year and still be dependant. The young will start to leave thereafter, and breeding can take place from the age of about 17 to 20 months. Otters in the UK generally only live for about 4-5 years, with the oldest recorded otter in Hampshire reaching 19 years.
The Otter has excellent hearing and well developed vision with its eyes placed at the top of the head to enable it to keep alert whilst the rest of the body is underwater. They have an acute sense of smell and their whiskers (Vibrissae) are very sensitive and extremely important for fishing in poor visibility. They communicate by using whistles, twittering noises and spitting sounds which can be heard at night time when it is quieter and still.
Otter faeces termed ‘spraints’ are generally 2-7cm long and will contain fish bones and scales, be tarry and black in appearance, but these will turn grey when old.
A fresh otter spraint (left) and an older spraint clearly showing fish bones (right).
Otters also produce an anal jelly which can vary in colour (opaque, yellow/orange, green, brown, black). Both spraints and anal jelly smell sweet and are often deposited on stones, boulders, logs etc along or around a waterbody.
Otter field signs: anal jelly(left) and tracks in bank side mud (right).
Otters are generally solitary, territorial animals, nearly always found beside water. They mainly live along rivers, but are also found extensively in and around canals, marshes, ponds, lakes, ditches, streams, and estuaries and along coasts.
Although otters travel large distances, most adults stay in a well-defined territory in which they feed, rest, and reproduce. Otter territories are measured as lengths of river bank or coast. The sizes of individual territories can depend on the quality of habitat, amount of food and even the number of ‘Holt’ sites available. Dog otters have much larger territories than bitches. One male otter’s territory generally overlaps those of several females. Otters patrol their beats constantly and defend their territory by using spraint as scent marking, but will also engage in direct territorial fighting. Territorial behaviour in otters helps to control population density by spacing out individuals. It also avoids over-exploitation of food resources.
Otters rest in underground dens (Holts) under waterside trees or in old rabbit burrows or in cavities in bank-side rocks. Otters also use above-ground resting places, called couches, built on the banks of a river, stream or lake, and occasionally further inland, often in thick vegetation or reed beds.
Population status -
Otters were on the verge of extinction in the 1950’s principally due to agricultural organochlorine pesticides being deposited into our river systems. Over a recent period of time they have been threatened in various ways such as habitat destruction which includes road building and new developments. Recovery in the otter population began in the 1980’s and by 2011 (with the exception of the Isle of Wight) otters were found in every English county. This recovery has in certain situations brought otters into conflict with fishery owners.
Numerous factors can affect fisheries, not simply predation. Similarly otter predation must not be confused with that of mink. Fisheries often provide otters with an abundance and easy to catch food source. Fisheries for instance that hold large specimen fish such as carp in an enclosed water, without other fish species will be at a higher risk than those with multiple fish species and various sizes.
The remains of a large carp predated by an otter.
When planning new fisheries and with the current and expanding otter population sensible measures and financial allowances should be built into the management plan. Where feasible - Otter proof fencing, electric fencing/netting can all dissuade otter predation and minimise risk to your fishery.
Conservation/protected status -
European otters and their holts receive full legal protection under both European & British legislation.
(Irrespective of the UK vote to leave the European Union in June 2016, the European Otter and their holts are still afforded full legal protection until such time that the legislation could be reviewed and if and where necessary alternative protections could be applied).
Otters are now protected principally under the Conservation of Habitats and Species Regulations (2010), with additional protection under the Wildlife and Countryside Act (1981), as amended by the Countryside and Rights of Way Act 2000.
The combined effect of these is that a person is guilty of an offence if he:
• deliberately captures, injures or kills any wild otter;
• deliberately disturbs wild otters including, in particular, disturbance which is likely to:
• impair their ability to survive, to breed or reproduce, or rear or nurture their young; or
• affect significantly the local distribution or abundance of the species;
• damages or destroys a breeding site or resting place of such an animal.
Or if he intentionally or recklessly:
• disturbs an otter while it is occupying a structure or place which it uses for shelter or protection; or
• obstructs access to such a place.
The Conservation of Habitats and Species Regulations provide for the granting of licences to prevent serious damage to livestock, foodstuffs for livestock, crops, vegetables, fruit, growing timber or any other form of property or to fisheries. However, a licence cannot be granted unless the licensing authority is satisfied:
• that there is no satisfactory alternative, and
• that the action authorised will not be detrimental to the maintenance of the population of the species concerned at a favourable conservation status in their natural range.
Licences for the prevention of damage in England are determined by Natural England.
Satisfactory alternatives might include exclusion techniques (e.g. fencing) or the use of deterrents. However, it should be noted that the use of deterrents themselves, in some circumstances, may require a licence.
Although licences can be issued for what would otherwise be offences under the various legislation, for conservation and development purposes (the latter only under the Habitats Regulations), strict criteria are used in assessing licence applications. As long as suitable alternative methods of resolving the problem exist, it is very unlikely that any licences would be issued to trap and remove otters which are predating a fishery, and such licences would normally be refused.
Otters are territorial animals, and removing an individual will create a vacuum which will be occupied by another otter in due course. This would therefore be only a short-term, ineffective solution, and not acceptable on conservation grounds for a European Protected Species.
Fishery Management & Fencing -
The amount of damage from otter predation to a fishery can be greatest where there are large, uniform ponds with poor marginal structure and little cover, and those which are populated primarily by large fish. Better fishery habitat management, introducing more marginal vegetation and woody debris for cover, and a healthier fish population age profile can sometimes help to reduce predation impacts.
Otters are resourceful and quite good climbers, so to be absolutely certain they can’t access a fishery a robust fencing specification is needed, with the greatest success achieved with fences which are buried in the ground at the base, have electric scare wires and an outward overhang. When the Environment Agency and Wildlife Trusts were producing their recommendations in the ‘Otters and Stillwater Fisheries’ guide, there was strong pressure from the fishing industry to recommend this robust solution as the preferred option, although it is expensive. Even with the high security solution, fishery managers and anglers have to remember to attend to weak spots and to secure the gates and then close them.
An example of a solid gate completing an otter proof fence - only effective if closed properly.
Funding opportunities –
The Angling Trust is aware of the tremendous pressures which predation can have on fisheries, whether that is cormorants, goosanders or otters.
To assist and help increase the availability of funding for angling, the Angling Trust, supported by the Environment Agency, launched the Angling Improvement Fund, which re-invests part of the proceeds of coarse and non-migratory rod licence sales in England in projects directly benefiting anglers. The Fund is open to all angling clubs and associations, commercial fisheries, charities and local authorities. Up to £5,000 is available for individual projects.
More details on how to apply, including key deadlines, standard application forms, and eligibility and judging criteria for each theme are available on the Angling Trust website at www.anglingtrust.net/AnglingImprovementFund
(Note: Unless otherwise credited photographs courtesy of UKWOT or Angling Trust).
1.Guidance on Environment Agency funding for fencing to prevent or reduce predation by otters on fish stocks HERE.
2.Otters: The Facts HERE
3.Joint statement on otter predation by the Angling Trust, EA and NE HERE.
4.Post Mortem Study of Otters found dead in England and Wales HERE
5.The Cardiff University Otter Project HERE
6.International Otter Survival Fund "Otters and Fisheries Conference Report" HERE
If your business or fishing has been affected by otter predation email us at
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