Water Quality and Fish Community Composition in the Sava Lake: The Basic Ecological Considerations

Tomislav Grozdić1, Milica Jaćimović1, Branislav Mićković1, Miroslav Nikčević1, Aleksandar Hegediš1 and Zoran Gačić1

 

1 Institute for Multidisciplinary Research, University of Belgrade, Kneza Višeslava 1, Belgrade, Serbia; E-mail: This e-mail address is being protected from spambots. You need JavaScript enabled to view it

 

Abstract

The aims of the present study are: 1) to present water quality data of the Sava Lake observed over a medium-term period; 2) to describe its fish community composition. Analyzed data were obtained from regular monitoring reports. Water quality parameters (dissolved oxygen, suspended solids, BOD, COD, total phosphorous and total nitrogen) were within the limits issued for I and II water quality classes. The Sava Lake inhabits 20 fish species from 19 genera, belonging to 8 families. Among the registered taxa, 2 families, 4 genera and 6 species are allochthonous. Calculated diversity indices were 0.143, 2.451, and 0.818 for Simpson's, Shanon-Weiner, and Evenness index, respectively. The F/C ratio was estimated as 4.18 indicating balanced community structure. Ecological classification provided information on intracommunity structure beyond the taxonomical level.

Keywords: Sava Lake, reservoir, fish community, ecological guild.

 

Introduction

On the Serbian territory, due to its geological and climatic history, there are only a few natural lakes. On the other hand, there are numerous artificial lentic water bodies (reservoirs, man-made lakes, gravel pits, ponds) and more are planned to be created. According to Čomić et al. (2003), investigations on hydrobiological characteristics of man-made water bodies in Serbia are insufficient. That is especially true concerning their fish fauna, where based on the survey data presented by the quoted authors, relevant descriptions on ichthyofauna are available for less than 10% of the total number of reservoirs in the country. Therefore, there is a need to examine all of the major man-made waters in Serbia to understand their fish community structure, especially those > 50 ha, which are recognized in Europe as being waters of substantial ecological and socio-economic significance (Launois et al., 2011).

There are several artificial lakes in the Belgrade area, which are used for recreation and angling. Among them the largest and most important is the Sava Lake. It is an urban lowland reservoir (N 44° 47' 02.28", EO 20° 23' 25.64"; 73 m a. s. l) with a surface area of approximately 90 ha, built up on the right branch of the Sava River. The lake is located approximately 4 km upstream from the Sava River confluence with the Danube.

The reservoir is slightly arched in shape and with a separate sedimentation section on its southern part (18.1 ha), from which the rest of the reservoir is supplied with water. Due to high anthropogenic influence (during summer season it hosts more than 100 000 people on a daily basis), since it was created the lake was subject to investigations concerning different aspects of its physico-chemical and biota characteristics (Čomić et al., 2003). Determination and assessment of water quality parameters give valuable information on the status, functioning and sustainability of the water body of interest. Tracking changes and status assessments of water quality parameters are a useful tool for identification of variation sources and their impacts on the functions and biodiversity of the reservoir (Mustapha, 2008). Surprisingly, the studies on its fish fauna have not been conducted so far. Recently, Hegediš et al., (2013) in the report on fishery resources in the Belgrade area provided preliminary information about the fish community of the lake. Authors stated that in the former period, lack of knowledge hindered a proper and sustainable management of fish populations in this water body. Beside this, Fishery Management Plans are additional sources on ichthyofauna of the lake. The aims of this paper are: 1) to present water quality data of the Sava Lake observed over a medium-term period; 2) to describe its fish community composition. Although of descriptive importance, the presented data might be useful in fish fauna management within proper management strategies, as well as for development of appropriate monitoring approaches. Moreover, data could be used in future studies on functioning and biodiversity of the reservoir.