Bathypelagic percid fry, a strongly predominating fry community in a deep European reservoir

0470179 - BC 2017 RIV NL eng J - Článek v odborném periodiku
Sajdlová, Zuzana - Jůza, Tomáš - Frouzová, Jaroslava - Seďa, Jaromír - Čech, Martin
Bathypelagic percid fry, a strongly predominating fry community in a deep European reservoir.
Hydrobiologia. Roč. 787, č. 1 (2017), s. 341-352. ISSN 0018-8158. E-ISSN 1573-5117
Grant CEP: GA ČR GP206/09/P266; GA MŠMT(CZ) EE2.3.20.0204; GA MŠMT(CZ) 7F14316
Institucionální podpora: RVO:60077344
Klíčová slova: echosounder * fry trawling * Gymnocephalus cernua * Perca fluviatilis * Sander lucioperca * shoals
Obor OECD: Ecology
Impakt faktor: 2.165, rok: 2017

The distribution, species composition, abundance and shoaling behaviour of young-of-year fish were studied in the canyon-shaped Vir Reservoir (Czech Republic) in mid-June 2010. Using the SIMRAD EK60 echosounder (frequency 120 kHz), fry were acoustically sampled along the longitudinal profile of the reservoir. A framed trawl was used simultaneously to collect fry in the open water. Apparent differences were found in the density of fry between the epipelagic, littoral and bathypelagic zones. Bathypelagic fry strongly predominated in the total fry community creating 95.3% while epipelagic and littoral fry contributed only 4.7%. The bathypelagic fry were represented by perch Perca fluviatilis (84.8%), zander Sander lucioperca (14.9%) and ruffe Gymnocephalus cernua (0.15%) and were observed all along the longitudinal profile of the reservoir creating a distinct layer on the echogram. The layer, composed of shoaling and non-shoaling fry individuals, reached its greatest depth in the Bay part of the reservoir (7.5-14.5 m) and it was rising in the water column towards the tributary. The situation that the bathypelagic percid fry predominate in the reservoir is absolutely unique and it is completely different from published observations from other canyon-shaped reservoirs where epipelagic percid fry prevailed.
Trvalý link: http://hdl.handle.net/11104/0267920