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Consumption of crucian carp ( C arassius carassius L ., 1758) by restocked pike ( E sox lucius L ., 1758) in a lake with frequent winter hypoxia
Author(s) -
Lappalainen J.,
Vinni M.,
Malinen T.
Publication year - 2013
Publication title -
journal of applied ichthyology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.392
H-Index - 62
eISSN - 1439-0426
pISSN - 0175-8659
DOI - 10.1111/jai.12284
Subject(s) - crucian carp , esox , pike , fishery , perch , rutilus , biology , cyprinidae , fauna , zoology , ecology , fish <actinopterygii>
Summary To assess the effects of stocked pike ( E sox lucius L .) on crucian carp ( C arassius carassius L .) biomasses, the annual consumption of pike was estimated and compared with removal fishery catches. The studied lake, L ake S avijärvi, is a small (40 ha), shallow and eutrophicated lake in southern F inland with frequent algal blooms during summers and fish kills during winters. Until the 1980s, the fish fauna consisted of pike, perch ( P erca fluviatilis L .), roach [ R utilus rutilus ( L .)], crucian carp, and tench ( T inca tinca L .). Since 2003, when crucian carp were abundant in the extreme and with only a few roach and tench individuals, the lake has been biomanipulated by removal seining. To enhance the effects of seining, piscivorous pike were restocked in the spring of 2008. During the 3‐year study, the catch of crucian carp decreased from 243 to 136 kg while the catch of pike increased from 0.1 to 5.7 kg per seining hectare due to their spawning in the lake as of 2009. The total crucian carp consumption by captured pike was 588 kg during the 2008–2010 study period. When applying the number of pike estimated with the mark‐recapture method, consumption estimate increased to 917 kg, or 22.9 kg per lake hectare in 2010. Thus, pike consumption of crucian carp was about 17% of the removal catch in 2010.