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

Previous | Contents | Next

Field Survey of Lutra lutra on Corfu Island (Greece)

Xavier Grémillet

SOS Otters Network, Maison de la Rivière, F-29450, Sizun, France

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

Figure 1. Corfu: Distribution of Otters in 1992 (click for larger version)

1. 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?
    
2. 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).
    
3. 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).
    
4. 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

1. Breeding:
   In 1992, from direct watching and footprints, otters still regularly breed in many freshwater, brackish and coastal wetlands of Corfu island.
    
2. 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.
    
3. Spraints:
   Spraints ware mostly found on white supports (natural or artificial): limestone rock, wood, plastic bag or box, polystyrene box.
    
4. 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.
    
5. 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: .

1. uncontrolled and booming of popular tourism: partial or complete illegal infilling, illegal building, straight sewage and litter dumpings in the wetlands.
2. 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.
3. 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:
   1. 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.
   2. 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.
   3. 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").

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.

Previous | Contents | Next