Field study

In the frame of the EU LIFE-Nature project for gizani conservation, research was undertaken, aiming at determining the geographic distribution of the species and the current state of its populations and habitats, as well as assessing the threats to gizani survival and sampling of fish specimens to study their biology and genetic composition.

Field data were collected during 14 sampling trips that were performed on a monthly basis (between February 1999 and March 2000) at lake Apolakkia and its inflowing streams and at the streams of Loutanis and Gadouras. Additional surveys were performed in most freshwater systems of Rhodes island, to confirm in each the presence or absence of gizani populations.

The routine sampling procedure included:

1. Determination of the co-ordinates of each sampling site with GPS.

2. Measuring of the main abiotic water parameters, i.e. temperature, dissolved oxygen, conductivity and salinity, by a portable Horiba polymeter. Water samples (of one litre volume each) were obtained from each site and transferred to the laboratories of the Institute of Inland Waters of NCMR for further chemical analyses.

3. Sampling of juvenile and adult fish, with a portable electrofishing device. With this method, fish get temporarily stunned; they are collected with hand nets and transferred into a small portable water-tank. After immediately measuring their body length and weight, they are released back into the stream.

In some cases that the water volume in the stream was too large, not allowing the use of an electrofishing device, sampling was performed with scoop nets.

In each sampling, a very small number of fish was transferred to the laboratory for further analyses (concerning morphometry, nutrition, reproduction, etc).

The artificial fertilisation of gizani was also carried out in the field.