Volume 8 Pages 1 - 47 (February 1993)
Citation: Grémillet, X. (1993) Field Survey of Lutra
lutra on Corfu Island (Greece). IUCN Otter Spec. Group Bull. 8:
39 - 42
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Field Survey of Lutra lutra on Corfu
Island (Greece)
Xavier Grémillet
SOS Otters Network, Maison de la
Rivière, F-29450, Sizun, France
Abstract: A study on Corfu Island in 1986
describes an otter population strongly threatened by building
activities and pollution from olive pressing factories. This
present report shows the accurate situation in 1992. Otters no
longer breed on the west coast, where two major populations have
been extirpated. Pressure from tourist development, fishfarming
and uncontrolled poaching, even in reserves, threatens remaining
otter populations. Conservation and restoration of the remaining
wetlands is urgently needed.
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INTRODUCTION
A recent study on Corfu Island in 1986 (Gaethlich
1988), describes an otter population strongly threatened by building
activities and pollution from olive pressing factories. This present
report shows the accurate situation in 1992, while the anthropic
pressure is dramatically increasing on the wildlife, especially on the
otter.
METHODS
This field survey was carried out only on the main island from 22
April 91 to 05 May 91, from 23 September 91 to 17 March 92 and from 27
April 92 to 13 June 92. The 8 sites studied by Gaethlich and all the
rivers and all the inland or coastal wetlands were regularly surveyed by
walking or canoeing. At each site a minimum of 2 km of shore or bank was
checked for all otter signs (spraints, tracks, "slides",
holts, resting sites). Beaches, sea cliffs out of reach on foot and less
suitable places were only sometimes visited and, unfortunately, never
once islets and small Islands. An inquiry was also conducted among the
Greek population, administration, fishermen and hunters.
STUDY AREA
Corfu (Kerkyra) is the north-westernmost island in the Ionian sea,
separated from the southern coast of Albania by a 2 km wide strait.
Along the west coast, there are high cliffs and long sandy beaches, but
very few rivers or water springs. On the opposite, the other coasts are
lower with some rivers, water springs, three large lagoons, some little
ones and the last salina. In 1974, 30 % of the whole area was occupied
by an old cultivated forest of olive trees, 30 % by other crops (vines,
fruit, vegetables). Now the 100 000 inhabitants gave up farming on
account of the tourism expansion. In 1991, 4374 charters and many
ferries conveyed a million tourists from May to October. There is no
intensive fish farming. Intensive livestock breeding or agriculture,
maize, or industry. So chemical pollution seems to be low, except in the
olive groves whore people use without circumspection a lot of toxic
sprays (e.g.gramoxone).
RESULTS
Otter distribution in Corfu
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Figure 1. Corfu: Distribution of
Otters in 1992 (click for larger version) |
- West coast and extinct otter populations:
It seems that there are no more otters on the west coast. A drainage
work reclaimed the wetlands of the Ropa valley (20 km2)
in 1904. The surviving population seems to have disappeared.
According to the hunters, it happened in 1968-1970 when the golf
course was constructed. The Korission lagoon (500 ha.) sheltered
otters in 1986 (Gaethlich). In spite of a
very close survey, no otter, nor spraint nor foot-print was found in
1992. The otter population was likely wiped out by hunters and
fishermen at request of the Italian fishing concessionaries. The
other parts of the west coast seem suitable for otters: food, holts
in undisturbed rocky places at the bottom of high cliffs, no
pollution and few tourist resorts. Is the lack of fresh water the
reason?
- Salina: Alikos/Lefkimmi:
This last salina (130 ha) does not shelter otters; it seems
unsuitable. Only footprints were found once on the beach (likely an
erratic otter).
- Rivers and estuaries:
On the north and east coasts, rivers are eutrophic and obstructed by
vegetation and dead trees. The banks are covered with a lush and
impenetrable vegetation. These sites are very suitable for otters
because they supply a lot for possibilities of food and holts. In
Melissoudi, Dasia/Daphnila and Potamos, the otters seem to be able
to bear organic pollutions from small litter dumpings and direct
domestic sewages. But the olive oil pressing units throw out water
directly into the rivers. This strong pollution appears to wipe out
the otters (e.g. in Chimaros no sign, in Mesongi few ones).
- Lagoons:
In the north, Antinioti lagoon (100 ha) shelters the most likely
important population of otters, in spite of the daily and strong
bird shooting from October to May. The reason is a huge reed bed
that provides food as well as quiet hides and holts without
pollution. In the north-east end, near Aghios Stephanos, 3 little
lagoons (each one, 2 ha) nearly free of main pollution and
disturbance are a cosy place for a coastal population. Surrounded by
Kerkya town and suburbs (30 000 inhabitants), Chalkiopoulou lagoon
still hides otters in spite of strong bird shooting, international
airport, pollution from direct sewage and large illegal infillings.
Biology/Ecology
- Breeding:
In 1992, from direct watching and footprints, otters still regularly
breed in many freshwater, brackish and coastal wetlands of Corfu
island.
- Dependence on freshwater:
The otter distribution appeared to follow the freshwater
localisation map. The lack of freshwater would seem to limit the
settling of coastal otters. Further confirmation is needed.
- Spraints:
Spraints ware mostly found on white supports (natural or
artificial): limestone rock, wood, plastic bag or box, polystyrene
box.
- Pollution and disturbance:
In Corfu, otters are able to live and bread very close to the
intense human activities in the suburbs and the crowded tourist
resorts; they often bear a heavy organic pollution. But in such a
case, otters absolutely require an easy sized and important prey
biomass, close refuges as well as the lack of chemical pollution.
- Dispersion:
Only a narrow strait (2 km) separates the large coastal wetlands of
south Albania from the most hopeful otter population of Corfu.
Presently, exchanges between these two populations are possible but
unknown
Survey among the human population
In Corfu, among the Greek population, exclusively fishermen and
hunters close to the lagoons know this animal. But only some of them can
supply some information about otters. The otters would have been
deliberately wiped out from Korission lagoon by fishermen. In the past,
they sometimes shot otters in Chalkiopoulou lagoon, and sold the pelts
in Kerkyra town.
Threats and otter conservation
In 1992, Corfu still shelters a population of otters. But this
species is really endangered. Saving otters means saving last
wetlands. This preservation requires some drastic measures. The
strongest threats are: .
- uncontrolled and booming of popular tourism: partial or complete
illegal infilling, illegal building, straight sewage and litter
dumpings in the wetlands.
- official policy of inaction: the economic expansion is free,
chaotic, without development scheme, but under the pressure of
foreign lobbies! Therefore offenders are rarely prosecuted. From
October to May, the poaching is a daily behaviour everywhere, even
within the 2 game reserves. The local administration asks for a
nature police and powerful game keepers team with real abilities and
powers.
- intensive fish farming schemes: supported by foreign lobbies, some
schemes threaten the great lagoons. The ecosystems would be
seriously altered by the discharges of droppings, the wastes of
chemical or pharmaceutical treatments and the introduction of
foreign species. The new conservation in Corfu urgently requires
three measures:
- Chalkiopoulou lagoon needs a restoration plan of the
traditional fishing ditches, the stopping of pollution and
infillings, the persecuting of the offenders; it would reconcile
the economic activities (fishing, tourism, suburb expansion)
with the requirements of the nature conservation.
- Aninioti lagoon needs a restoration of the huge reed beds to
the advantage of fishermen, birds and otters. The successful
restoration of "La Gabrière" lake in Brenne/France (Trotignon
& Williams 1990) should be an excellent example for
Antinioti.
- A nature sanctuary for the 3 little lagoons near Aghios
Stephanas. The very limited size and the lack of building,
pollution and main disturbance on this area is an opportunity to
establish a nature sanctuary ("Otter Haven").
CONCLUSION
The otter still breeds in freshwater, brackish and coastal wetlands
of Corfu. The species is therefore endangered by tourism expansion.
Otter conservation requires a real policy of conservation for the
remaining wetlands.
ACKNOWLEDGEMENTS - Lionel Lafontaine (S.O.S.
Otters Network Coordinator) made very helpful comments on early drafts
of this manuscript. I thank him for his advice.
REFERENCES
Gaethlich, M. (1988). Otters in
western Greece and Corfu. I.U.C.N.
Otter Specialist Group Bulletin, 3: 16-23.
Trotignon, J. & Williams, T. (1990).
Favoriser la vie dans les élangs. Atelier technique des espaces
naturels. 68 p.
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