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Ljunggren, Lars
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Publications (3 of 3) Show all publications
Ljunggren, L. & Sandström, A. (2007). Influence of visual conditions on foraging and growth of juvenile fishes with dissimilar sensory physiology. Journal of Fish Biology, 70(5), 1319-1334
Open this publication in new window or tab >>Influence of visual conditions on foraging and growth of juvenile fishes with dissimilar sensory physiology
2007 (English)In: Journal of Fish Biology, ISSN 0022-1112, E-ISSN 1095-8649, Vol. 70, no 5, p. 1319-1334Article in journal (Refereed) Published
Abstract [en]

The influence of turbidity on foraging and growth of young-of-the-year (YOY) of two percid species with relatively dissimilar sensory physiology, perch Perca fluviatilis and pikeperch Sander lucioperca was tested. A littoral mysid, Neomysis integer, was used as prey. Functional response was investigated indoors at two levels of turbidity, 3 NTU (clear) and 25 NTU (turbid). Growth and consumption rate were studied both during day and night in outdoor experiments at similar turbidity levels. Pikeperch were not affected by turbid conditions in either of the experiments. Foraging of perch, on the other hand, was significantly negatively affected by higher turbidity in the functional response experiments and during the night-time in the outdoor experiments. As opposed to pikeperch, consumption rates of perch decreased markedly during nights. Perch also grew more slowly in the treatments with turbid water. The dissimilar reactions of the two species indicate that sensory physiological adaptations and foraging behaviour are important factors that partly can explain disparate reactions of YOY fishes to the level of turbidity.

Keywords
Foraging, Growth, Perch, Pikeperch, Turbidity, Visual
National Category
Biological Sciences
Identifiers
urn:nbn:se:miun:diva-8465 (URN)10.1111/j.1095-8649.2007.01412.x (DOI)000245813000001 ()2-s2.0-34247389685 (Scopus ID)
Available from: 2009-01-26 Created: 2009-01-26 Last updated: 2017-12-14Bibliographically approved
Ljunggren, L., Staffan, F., Falk, S., Linden, B. & Mendes, J. (2003). Weaning of juvenile pikeperch (Stizostedion lucioperca (L.)) and perch (Perca fluviatilis (L.)) to formulated feed.. Aquaculture Research, 34(4), 281-287
Open this publication in new window or tab >>Weaning of juvenile pikeperch (Stizostedion lucioperca (L.)) and perch (Perca fluviatilis (L.)) to formulated feed.
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2003 (English)In: Aquaculture Research, ISSN 1355-557X, Vol. 34, no 4, p. 281-287Article in journal (Refereed) Published
Abstract [en]

Weaning success of pond-cultured pikeperch and wild-caught perch (mean length 51 and 48 mm respectively) was evaluated using different weaning techniques and different formulated feeds. Juveniles that were fed formulated feed grew as well as or better than juveniles that were weaned successively using zooplankton or yolk. Four different formulated feeds (agglomerated marine larvae feed, marine larvae feed, trout feed and a semi-moist feed) were evaluated regarding specific growth rate (SGR), condition factor and a subjective stomach fullness estimate. The agglomerated marine larvae feed gave significantly better weaning performance than the other feeds regarding all parameters (SGR = 7.3% day(-1) and 3.4% day(-1) for pikeperch and perch respectively).

Keywords
Pike, perch, juvenile, formulated feed, growth, survival
National Category
Biological Sciences
Identifiers
urn:nbn:se:miun:diva-2664 (URN)000181398000002 ()2-s2.0-0037466108 (Scopus ID)2069 (Local ID)2069 (Archive number)2069 (OAI)
Available from: 2008-09-30 Created: 2008-09-30 Last updated: 2016-10-24Bibliographically approved
Ljunggren, L. (2002). Growth response of pikeperch larvae in relation to body size and zooplankton abundance. Journal of Fish Biology, 60(2), 405-414
Open this publication in new window or tab >>Growth response of pikeperch larvae in relation to body size and zooplankton abundance
2002 (English)In: Journal of Fish Biology, ISSN 0022-1112, E-ISSN 1095-8649, Vol. 60, no 2, p. 405-414Article in journal (Refereed) Published
Abstract [en]

The most critical period at onset of feeding in pikeperch Stizostedion luc\ioperca is short (<5 days at 20degreesC). The larvae are sensitive to prey density during the first week of exogenous feeding. First-feeding larvae of 6.5 mm total length (L-T) needed prey densities of >585 prey l(-1) to maintain mass (C-maint), whereas 5 days older larvae of 7 mm L-T C-maint=55 prey l(-1) and for 11 mm L-T larvae C-maint <10 prey l(-1). Changes in specific growth rates for larvae of 7 and 11 mm were similar to a type-II functional response curve reaching a specific growth rate of 26 and 30% day(-1), respectively, at 1000 prey l(-1), whereas the 6.5 mm larvae showed a linear growth response reaching a specific growth rate of only 9% day(-1) at 1000 prey l(-1). The results suggest that prey density is a limiting factor, which might contribute to the high variation between year-class strengths.

Identifiers
urn:nbn:se:miun:diva-13663 (URN)10.1006/jfbi.2001.1852 (DOI)000174505100011 ()
Available from: 2011-04-20 Created: 2011-04-20 Last updated: 2017-12-11Bibliographically approved
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