Losing Paradise – The threatened aquatic biodiversity of Corfu

Does the Mediterranean Killifish Aphanius fasciatus have a future at Erimitis?

The Erimitis coast is an area of outstanding natural beauty in Corfu. It was long considered to be a protected site that would remain undeveloped and unspoilt for future generations to enjoy. A large area of the Erimitis coast has now been sold to the tourist industry and this development threatens an important population of the Mediterranean Killifish Aphanius fasciatus in one of the lakes.

The brackish, freshwater, marine and terrestrial habitats of Erimitis support a flora and fauna of regional and international importance. To take one example, Neptune grass Posidonia oceanica seabeds provide vital ecosystem services, from the nurseries that nurture developing juvenile fishes and crustaceans, upon which many other organisms (and commercial fisheries) rely, to the stabilisation of sediment that provides the water quality and clarity associated with popular tourist destinations. The Neptune grass seabeds of Erimitis, which elsewhere, are routinely protected through legal designation e.g. as Natura 2000 sites, are now threatened directly, through the proposed construction of a marina, and indirectly, through the associated input of nutrients into this marine environment.

There are three lakes in this region: Savoura Marsh, Akoli (Figure 7) and Vromolimni (Figure 8), each of which has its own distinct natural history in accordance with observed levels of salinity.

The most southerly lake, Vromolimni, which forms part of the area sold for development, holds a population of the Mediterranean Killifish. This species is a Mediterranean basin endemic and is listed for protection in Annex II of the Habitats Directive and the Bern Convention. Zogaris (2017) writes: “Although assessed as “Least Concern” in the IUCN red list it is locally threatened in many parts of its range; relatively few island populations exist, and in many places, they have become locally extirpated.”

Figure 7. European Pond Terrapin Emys orbicularis at the middle lake, Akoli, at Erimitis. This lake supports a thriving community of aquatic crustaceans and other invertebrates such as the Small Red-eyed Damselfly Erythromma viridulum and the Blue-eyed Damselfly Lindenia erythromma. These provide food for the European Pond Terrapin and other inhabitants, and make the area an important stopover point for migrating birds.

It is possible that the Mediterranean Killifish may once have been present in all three lakes, but as with the Corfu Toothcarp, the introduction of the Eastern Mosquitofish in the Savoura Marsh and Akoli lakes is likely to be the cause of its disappearance. It is also likely that the Mediterranean Killifish continues to survive in the third lake because it has a level of salinity that the Eastern Mosquitofish cannot tolerate.

Figure 8. The Erimitis Coast is an area of outstanding natural beauty whose varied terrestrial, fresh and brackish water, and marine habitats collectively support an internationally important flora and fauna (top left). Delegates from the Gerald Durrell Week (top right) observe schools of Mediterranean Killifish Aphanius fasciatus (bottom left) in the brackish water lake, Vromolimni, which is threatened by commercial development. A flamboyant male Mediterranean Killifish in breeding colours (bottom right).

The commercial development of the Erimitis coastline has already caused local damage to the area and may lead to the disappearance of the Mediterranean Killifish at this site (Figure 9).

Figure 9. The development of the Erimitis Coast has already caused damage to the brackish water lake,Vromolimni. (Photographs: © Xenia Tombrou)