TITLE:
Shifts in Prey Selection and Growth of Juvenile Pikeperch (Sander lucioperca) over Half a Century in a Changing Lake Võrtsjärv
AUTHORS:
Kai Ginter, Külli Kangur, Andu Kangur, Peeter Kangur, Marina Haldna
KEYWORDS:
Climate Change; Eutrophication; YOY Pikeperch; Long-Term Changes; Diet Shift; Stomach Content Analysis
JOURNAL NAME:
Open Journal of Applied Sciences,
Vol.2 No.3,
September
28,
2012
ABSTRACT: Analysis of historical and recent data is essential to understand how eutrophication and/or climate change might trigger shifts in the feeding mode of fish and trophic dynamics of shallow lakes. To assess long-term changes in the diet and growth of juvenile pikeperch (Sander lucioperca), the prey selection and growth of pikeperch fry from Lake Võrtsjärv was investigated in 2007 - 2010 and compared with data from 1920 to 1970. Over the observed period, larger cladocerans have become less frequent in the diet as eutrophication has altered the zooplankton community. Furthermore, climate change has triggered a mismatch between the predator and its prey: the smelt population has collapsed but other fish fries are too large for YOY (young-of-the-year) pikeperch. However, the mean length of fish has decreased mainly due to the postponed diet shift.