Lake Aluksne fish community - it`s compotition and fish feeding habits in the summer season 2014

Bakalaura darbs izstrādāts Vides Risinājumu institūta un Alūksnes novada pašvaldības projekta „Alūksnes ezera gultnes, piekrastes zonas veģetācijas un ekosistēmas pētniecība” ietvaros. Darbā mērķis bija raksturot Alūksnes ezera zivju sabiedrības sastāvu un izpētīt dominējošo zivju sugu barošanās paradumus. Zinātniskā kontrolzveja pamatā veikta pēc Eiropas un Latvijas zivju paraugu ievākšanas standarta, izmantojot Nordic tipa daudzacu žauntīklus. Konstatēts, ka Alūksnes ezera zivju sabiedrība atbilst mērenās klimata joslas mezotrofu ezeru ihtiofaunai un ka no konkrētām zivju sugām gan pēc biomasas, gan pēc skaita dominēja asari Perca fluviatilis. Saistībā ar zivju barošanās paradumiem secināts, ka Alūksnes ezerā zivju galvenie barības objekti ir zoobentoss un zooplanktons, no kuriem zivis visbiežāk barojušās ar trīsuļodu kāpuriem un Daphnia cucullata.Bachelor thesis has been developed within the framework of the Project „The Study of Lake Aluksne: bed, costal vegetation and ecosystem” run by the Institute for Environmental Solutions and Aluksne Regional Government. The objective of the research was to describe Lake Aluksne fish community and to explore feeding habits of the dominating fish species. Scientific fishing basically was performed following the standards for collection of fish samples set by the European and Latvian authorities, using Nordic multimesh gillnets. It was found that fishes in Lake Aluksne correspond to the fish fauna characteristic in mesothropic lakes of temperate climate zone, and that perches Perca fluviatilis were the dominating species judging by biomass and quantity of the inspected fishes in the lake. With regards to feeding habits of the fishes it was concluded that the main food of fishes in Lake Aluksne is zoobenthos and zooplankton, out of which most frequently the fishes have chosen Chiromomidae larva and Daphnia cucullata