ASSEMENT OF THE ECOLOGICAL STATUS OF THE CRNA RIVER
BASED
ON THE FISH FAUNA – CONTRIBUTION TO THE ESTABLISHEMENT
OF THE MONITORING SYSTEM OF RIVERS
IN R. MACEDONIA
Vasil Kostov1,
Milica Ristovska2. Dana Prelić2, Valentina
Slavevska-Stamenković2
1“Ss.
Cyril and
Methodius“ University in Skopje, Institute of Animal Science, Fisheries Department,
Bul. Ilinden 92a, 1000 Skopje, Republic of Macedonia
2Faculty of Natural Science and
Mathematics, Institute of Biology,
P.O. Box 162, 1000 Skopje, R. Macedonia
vasilkostov@yahoo.com
The purpose of this study is to assess the
longitudinal variation of species composition and the community
structure of ichthyofauna from the Crna River,
as well as
the assessment of the ecological status of
the river based on the fish fauna. The
investigation is made on 12 sampling points on the river during August,
September and October 2006 including the reservoir Tikveš. Twenty nine
species belonging to 9 families have been recorded. Among them 21 are
autochthonous (native) species and 8 are allochthonous ones. The
structure of fish community is evaluated by using structural indices of
species richness – d, diversity H’, homogeneity – J(e)
and similarity (S). Reduction of fish diversity could be noticed along
the river course. It seems that changes in the habitat condition mainly
associated with human activities are the main factors which alter the
structure of fish community. EFI values indicate a healthy, natural or
nearly natural water ecosystem or good ecological status along the river course from the source
region to the sampling point T3. After the inflow of
the River Blato, at the profile “Trojkrsti” (T4), the
ecological status deteriorates. The remaining downstream parts of the
river has a moderate ecological status, except the profile below the town
of Bitola,
which according to the EFI has a bad ecological status. Below the “Skočivir”
profile, the water quality improves toward moderate status. The use of
selected parameters of the community is found to be the effective basis
for further development of the system of the ecological status assessment
based on the fish fauna.
Keywords: fish community structure; structural
indicies; EFI; Crna
River; Rpublic of Macedonia
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