Volume 3 Pages 1 - 51 (March 1988)
Citation: Braun, A.-J. (1988) The Otter (Lutra lutra)
in Brittany. IUCN Otter Spec. Group Bull. 3: 5 - 8
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The Otter (Lutra lutra) in Brittany
Étude Loutre, 56370 Le Tour du Parc, Le Mare, Brittany,
Brittany (NW France) is a massive, low-lying peninsula with a highest
altitude of only 390m. The drainage system is dense but rlvers are usually
short, few exceeding 100 km in length. The climate is oceanic, mild and with
moderate rainfall. Brittany covers 34.077 sq km with a population of 3,530,000
Until the mid 1950s the otter was common and locally abundant throughout the
province and exploited all available habitats fron small oligotrophic streams
(less than 2m wide) and large eutrophic rivers to wetlands, sea coasts and
islands. Regarded as a pest, it was intensively trapped and hunted, frequently
with packs of hounds in the British manner but in a less organised way. Tallies
for otter hunts ranged from 5 to over 60 animals per year during the period
1930-1970. Poisoning with strychnine also occurred in the Loire area, in the
south, but with negligible results. It has been estimated (Braun,
during the period 1930-1970, between 16,000 and 40,000 otters were destroyed
A decline was first noted by otter hunters and trappers during the 1950s and
early 60s. We cannot say if it coincided with the appearance of pesticides or
not (see Chanin & Jefferies, 1978). Very few fish have been analysed
recently for pesticides and heavy metals (only 49 samples). One sample from the
Ille at Vilaine departement contained 0.595 mg/kg fresh weight, which is higher
than the maximum level of 0,5 mg/kg set by the National Academy of Sciences
(USA). Mercury was found in fish from several rivers in all the departemants of
While industry in Brittany has remained on a small scale, slaughter houses ,
canning factories, fish farming and poultry units have grown tremendously and
have generated locally high levels of pollution. Many streams are in a state of
neglect, obstructed by dead vegetation and which results in low biological
productivity. Some streams are being reconstituted by conservation groups.
However, at present, the general situation of rivers is relatively good,
especially by comparison with other regions, e.g. the north and east, of France.
The present distribution of Lutra lutra is not accurately known
because of a lack of specialists and due to differing and uncoordinated survey
methods. According to our own information (from field surveys and informants),
the species has disappeared from most of the islands and sea coast but is still
found inland, especially in headwaters in the central part o£ the region. In
the southern regions of Morbihan and Loire Atlantique otter populations live in
coastal marshes and sometimes use the sea shore and estuaries. Breeding occurs
regularly in 4 departements - Finisterre, Cotes du Nord, Morbihan and Loire
Atlantique. In Ille et Vilaine breeding seems to be very irregular. The largest
and most healthy population appears to live in Morbihan. Records collected since
1970 show that the mean number of young per litter in Brittany is 3.2 (n = 13)
(Braun, 1986 and unpublished).
Between 1970 and 1987 causes of otter mortality in Brittany were recorded (Braun,
1986 and unpublished). The results are given in the
|Table 1: Causes of Otter Mortality
The figures for traffic accidents appear very high compared to other European
regions - c.f., for example, 18% in Czechoslovakia (Barus and
Zejda, 1981) or 10.6% in the German Democratic Republic (Stubbe,
1980). Could this be due to a higher density of otters in our region? In 22
cases (73.3%), the otter was killed on a road/bridge crossing a wetland or
separating two wetlands. In 25 cases (83.3%) the accidents occurred in areas
where the species is considered as breeding regularly.
Trapping to control "pest species" such as muskrat (Ondatra
zibethicus), coypu (Myocastor coypu) and mink (Mustela vison)
is widely practised. Since the last 10 years the American mink has colonized
most of the suitable habitats in 3 departements -Morbihan. Finistere and Cotes
du Nord. Locally the species is abundant and this has led to an increase in
trapping. The use of gin traps, even when these are modified (a law requires the
teeth to be filed off or covered with plastic or rubber) is still a threat to
otters as well as to the highly endangered European mink (Mustela lutreola)
which survives in very low numbers in Brittany. Evidence of Mustela vison
was found in over 65% of the sites used by otters in Morbihan. Proposals made by
the author in 1983 to use cage traps in areas frequented by Lutra lutra
and Mustela lutreola were approved by the Morbihan Hunters Federation in
1987. It is hoped that this will soon be extended to other departments.
All recorded otter deaths by drowning occurred in southern Brittany (Morbihan
and Loire Atlantique) where eel nets are commonly set. Braun
(1983) recommended the use of excluders on fyke nets but no decision has
Poisonous baits (poison type unknown) were laid to get rid of muskrats over a
large marsh in Morbihan, resulting in the death of an entire family. Dogs also
cause problems especially during the breeding season. The 4 otters killed by
dogs were estimated to be aged 3-4 months old. Castor fiber was
introduced in Finistere in the 1960s and 70s. Fights between beaver and otter
occurred twice, each time an otter being killed. Braun (1986) suggests that
otters should not be re-introduced in areas where beaver exist.
In conclusion, while the situation of the otter in Brittany seems much better
than in many other regions of France, it appears that many threats still exist.
Some could be stopped or substantially reduced with the enacting of laws such as
mandatory use of cage traps and excluders for fyke nets. Education and training
of shooters and trappers should emphasize the conservation of Lutra lutra
and Mustela lutreola and include methods for selectively trapping only
target species. Traffic accidents could be reduced by installing reflectors near
bridges and by modifying culverts. A study of this problem has been carried out
by the author on behalf of the Regional Road Department which should lead to
some conservation measures being taken in 1988. Finally, 3 otters are being
analysed for organochlorlnes since we know little of the effects of pollution on
Conserving the otter in Brittany is a real challenge for naturalists but
unfortunately specialists are few and funding is very restricted. More studies
should be made as well as a complete and well organized regional survey.
Informing the public is another task which the author initiated in 1982. His
slide programme has been shown to over 10,000 people all over Brittany and a
large exhibit was organized at the Museum of Natural History in Nantes (10,000
visitors). The WWF-France has given financial assistance to the author but more
money is needed if we are to save this fascinating species!
Barus, S. and Zejda, J. (1981). The European otter
(Lutra lutra) in the Czech Socialist Republic. Acta Sc. Nat. Brno.
Braun, A.-J. (1983). Repartition de Lutra
lutra L. dans la zone du Lac de Grandlieu (Loire-Atlantique). Premiere phase
1981-82. Unpublished internal report to WWF-France. 15 pp.
Blanchon, J. J. and Braun, A.-J. (1983). Statut de
la loutre sur la basse Vallee de la Bouzanne (Indre). Groupe Loutres Sfepm/Direction
Departementale de L'Agriculture/Delegation Regionale a l'Architecture & a
l'Envlrormement, Region Centre. 13 pp.
Braun, A.-J. (1984). A brief history of Lutra
lutra in Brittany. Unpublished report (in English). 12 pp.
Braun; A,-J. Causes de mortalite chez Lutra lutra en
Bretagne & propositions de mesures destinees a reduireles pertes: 1970-1986.
Unpublished report to WWF-France. 9 pp.
Braun, A.-J. (1986). Causes of otter mortality
in Brittany (1970-1985). Unpublished report to Vincent Wildlife Trust (In
English). 7 pp.
Braun. A.-J. (1986). La loutre en Bretagne.
Statut et repartition. Impact des amenagements, en particulier en riviere.
Propositions de mesures de sauvegarde. Delegation Regionale a l'Architecturc
& l'Environnement, Rennes. 45 pp.
Stubbe, M. (1980). Die Situation des Fischotters in
der D.D.R. In Reuthar, C. and Festetica, A. (1900). Der Fischotter In Europa -
Verbreitung, Bedrohung, Erhaltung. Selbatverlag, Oderhaus and Gottingen. pp.
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