**4.4 Hydrogeology**

Monitoring of the ground water level (GWL) of the ground water facilities (boreholes, wells) was executed occasionally (once per month) in the 12 month period (from March 2010 to February 2011). The measuring was performed using an electrical water level meter (type GTS, made in Italy) equipped with lightening and sonorous signal. In the case of the presence of artesian ground water level (which is expected in Pl3 sediments – GW6), the monitoring was executed by measuring the natural capacity [l/sec] of the well.

#### **4.5 Macrophytes**

Monitoring of macrophytes in Lake Prespa was performed in the period from April to May 2010 and from August to September 2010 on five locations along the Macedonian coastline: Stenje, Golema River, Krajnska River, Brajcinska River and Dolno Dupeni.

The macrophytes field survey methods which have been used in the biological monitoring of Lake Prespa were consistent with the Water Framework Directive: a) **characteristic zonation -** determination if all type-specific vegetation zones for this Lake; b) **preparing the lists of species present in a lake (floristic inventories) -** determination of collected plant species using different floras and keys; c) **determination of vegetation density -** which focuses on the overall abundance of macrophytes. Abundance were estimated on a fivepoint scale (Braun-Blanquet 1964) where 1 = very rare, 2 = infrequent, 3 = common, 4 = frequent and 5 = abundant. The vegetation density is the result of different pressures, such as alteration of the shoreline, artificial water level fluctuations, artificial wave action and the trophic state; d) **mapping of lake's vegetation** (phyto-littoral mapping) - according to this method, the qualitative composition and distribution of aquatic vegetation was investigated.

#### **4.6 Fish**

Fish for analyses were collected with various fishing gear in day and night time experimental fishing. A cast net was also used for day time fishing with mesh size of 13 mm, whereas the night time fishing was performed with bleak nets (mesh size from 12 mm and 13 mm), and barbell nets with mesh size of 22 mm, 24 mm, 26 mm and 28 mm. The height of each fishing gear was basically a hundred heights per each mesh and the length was about 50 metres. All nets were set between 3 and 6 pm, fished overnight and lifted between 8 and 10 am in order to ensure that the activity peaks of each fish species was included.

The location of each net was selected according to proposed sampling sites in the project and based upon the past experience of the investigator.

All captured fish were identified, and length and weight was measured. The age and sex composition of the fish population from Lake Prespa were performed with standards ichthyological methods. Analyses of the scales were used for determination of the age structure of the fish populations, as well as length and weight growth. The obtained results were statistically processed.
