Rapid population collapse of<br /> the critically endangered Valencia letourneuxi in Kalamas basin of Northwest Greece.
Journal Title: Aquaculture, Aquarium, Conservation & Legislation - International Journal of the Bioflux Society - Year 2010, Vol 3, Issue 2
Abstract
In order to assess the current status of the critically endangered Valencia letourneuxi in Kalamas River basin, an extensive field survey including twelve sampling stations was undertaken using back-pack electrofishing device, D-shaped frame net and small mesh size nets in October 2008. In total, 552 fish specimens were collected, belonging to ten freshwater fish species, plus mullets (collectively grouped as Mugil spp.). V. letourneuxi was found at one station (Anakoli ditch) (8.3% of sampling stations), at very low relative density (0.95%), where it co-occurred with the loach Cobitis hellenica, the goby Economidichthys pygmaeus and the introduced Eastern mosquitofish Gambusia holbrooki, with the last at very high relative densities. Moreover, water samples from selected stations were phasmatophotometrically analysed for ΝΗ3-Ν, ΝΗ3, ΝΗ4, ΝΟ2-Ν, ΝΟ2, ΝaΝΟ2, NO3-N, NO3, PO4, P and P2O5. Overall, V. letourneuxi was extirpated from one of its two previously known populations in this basin and its single surviving population was characterized by low local relative density and steep decline in relation to recent records (2005). Moreover, the presence at very high densities of the G. holbrooki as well as the increased eutrophication (due to high ammonia and phosphorus inputs) in its highly modified habitat, suggest a rapid population collapse with significant risk of extirpation from Kalamas basin in the near future. The necessary conservation measures are outlined.
Authors and Affiliations
Costas Perdikaris, Ioannis Paschos, Evangelia Gouva, Evangelos Pappas, Eleni Kalogianni
Keywords
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