The structure of fish community in the river Mirna

Jakopin, Jasmina (author), Toman, Mihael Jožef (author)

Natural perturbations and human pressure increasingly affect the river ecosystems and their biological communities. Fish species are a good indicatorof the river status and one of the factors for the assessment of ecological condition by the Water Framework Directive (Directive 2000/60/EC). River Mirna, one of the larger right tributaries of the river Sava, is a good example of anthropogenic pressure on the running water ecosystem. Fish community species structure was analyzed at selected eight sampling sites located over the 28 km length of the river. Abiotic conditions were determinedby measuring the physical, chemical and hydro-morphological parameters and the influence of measured parameters on present fish community was analyzed. It has been determined, that the river Mirna is loaded with organic matter and physically changed by regulations, river beds canalizing and bank stabilization. Fish were sampled with standard electro-fishing methodto determine species diversity, biomass of the specimens and their size.29 fish species from seven families (26 native and 3 allochthonous species) were recorded along with one type of the Danubian brook lamprey (Eudontomyzon vladykovi). Only two species, Telestes souffia and Cottus gobio,were present at all eight sampling sites. The largest number of specimens (890) and the largest biomass (5697 g) per 100 m2 was recorded at the sampling site located after the town as a result of the flow of purified water from the water treatment plant and a large number of invertebrates, which are an important food source. The minimum number of specimens per 100 m2(86) and the minimum biomass of fish per 100 m2 (457 g) was measured at the relatively natural part of the channel. The most common causes for this are low temperatures, less food and a fast, turbulent flow. The study confirms that the changes in abiotic factors induced by anthropogenic activities significantly influence the structure of fish species community.

• Language: English
• Keywords: running waters, loading, anthropogenic pressure, fish community, fish biodiversity
• Work type: Not categorized
• Typology: 1.01 - Original Scientific Article
• Organization: BF - Biotechnical Faculty
• Year: 2012
• Number of pages: Str. 39-48
• Numbering: Vol. 55, št. 2
• PID: 20.500.12556/RUL-37661
• UDC: 574.5
• ISSN on article: 1408-3671
• COBISS.SI-ID: 2704207
• Publication date in RUL: 10.07.2015

Record is a part of a journal

• Title: Acta biologica slovenica
• Shortened title: Acta biol. slov.
• Publisher: Društvo biologov Slovenije
• ISSN: 1408-3671
• COBISS.SI-ID: 68526592

Secondary language

• Language: Slovenian
• Title: Struktura ribje združbe v reki Mirni

Abstract

Naravne motnje in naraščajoči vplivi človeka vedno močneje vplivajo na rečne ekosisteme in njihove življenjske združbe. Ribje vrste so dober pokazatelj stanja reke in eden od elementov za oceno ekološkega stanja po okvirni vodni direktivi (Direktiva 2000/60/ES). Reka Mirna, eden večjih desnih pritokov rekeSave, je dober primer antropogenega vpliva na ekosisteme tekoče vode. Vrstno strukturo ribje združbe smo analizirali na izbranih osmih vzorčnih mestih na dolžini 28 km reke. Z meritvami fizikalnih, kemijskih in hidromorfoloških parametrov smo ugotavljali abiotske razmere in analizirali vplive merjenih parametrov na prisotno združbo rib. Ugotovili smo, da je ACTA BIOLOGICA SLOVENICA LJUBLJANA 2012 Vol. 55, [t. 2: 39-48 40 Acta Biologica Slovenica, 55 (2), 2012 reka Mirna obremenjena z organskimi snovmi in fizično spremenjena z regulacijami, kanaliziranjem struge in utrjevanjem brežin. Ribe smo vzorčili z elektroagregatom, določili vrstno pestrost, biomaso osebkov in njihovo velikost. Evidentirali smo 29 vrst rib iz sedmih družin (26 avtohtonihin 3 alohtone vrste) in eno vrsto donavskega potočnega piškurja (Eudontomyzon vladykovi). Le dve vrsti, Cottus gobio in Telestes souffia, sta bili zastopani na vseh osmih vzorčnih mestih. Največje število osebkov na 100 m2 je bilo na vzorčnem mestu za naseljem (890), z največjo ocenjeno biomaso na100 m2 (5697 g), kar je posledica dotoka očiščenih vod iz čistilne naprave naselja in večje število nevretenčarjev, ki so pomemben vir hrane. Najmanjše število osebkov na 100 m2 (86) in najmanjšo biomaso rib na 100 m2 (457 g) smo ugotovili na izvirnem delu struge. Najpogostejši vzroki za takšno stanje so nizka temperatura, manj hrane in hiter, turbulenten tok. Potrdili smo, da spremembe abiotskih dejavnikov, ki jih sprožijo antropogene aktivnosti, signifikantno vplivajo na vrstno strukturo ribje združbe.

• Keywords: tekoče vode, obremenjevanje, antropogeni vplivi, združba rib, diverziteta ribjih vrst