Field observations and laboratory experiments on growth and lipid content of young-of-the-year perch

Abstract

Differences in growth and allocation of energy of youngof-the-year (YOY) perch (Perca fluviatilis) were studied in relation to both quantity and quality of food. Feeding on fish and Mysidacea, the mean size of YOY perch after the first growing season in Lake Pfeiffer was 152 mm. In contrast, YOY perch grew to 107 mm in Lake Speldrop and 83 mm in Lake Reeser Meer while mainly feeding on zooplankton. In correlation with food uptake and growth, the lipid content of YOY perch was significantly highest in Lake Pfeiffer and lowest in Lake Reeser Meer, assuming that YOY perch from Lake Pfeiffer should be able to survive starvation periods during their first winter better then those from Lake Speldrop and Lake Reeser. While feeding on fish, mean highest growth rates were 1.31 mmAEday )1 in the laboratory. Growth in weight started when food uptake exceeded 66 JAEg WW )1 AEday )1 , while an increase of lipid content required food input of 175 JAEg WW )1 AEday )1 . Increased growth potential associated with the availability of energetically profitable food is assumed as an important factor that could have far-reaching consequences for the fish community.

Distribution, ecology and impact of a small invasive shellfish, Hemimysis anomala in Alsatian water

“…During night dives, we observed predation of H. anomala by bullheads (Cottus gobbio), larvae of dragonflies (Calopteryx virgo) and perch (Perca fluviatilis), confirming work of Kelleher et al in 1999, who found H. anomala in the stomach of perch in the delta of the Rhine in Holland. Others have come to the same conclusion (Borcherding et al 2007;Hermasch and Murawski 2007). The light of our projectors certainly disturbs the behavior of the animals and facilitates detection of H. anomala by predators, but it also makes it possible to highlight that many species eat this small shellfish.…”

Selective zooplanktivory of an invasive Ponto-Caspian mysid and possible consequences for the zooplankton community structure of invaded habitats

“…For this experiment, daphnids (D. galeata and D. hyalina) as well as L. benedeni were collected from Lake Speldrop, a small gravel pit lake near the Ecological Field Station in Rees-Grietherbusch (Borcherding et al 2007). In contrast to Lake Reeserward II, this lake is not connected to the River Rhine.…”

Energy allocation strategy modifies growth–survival trade-offs in juvenile fish across ecological and environmental gradients

“…Organisms distributed across geographical gradients experience variation in stored energy requirements and patterns of higher storage in areas with harsher winters have been observed along latitudinal (Schultz and Conover 1997;Berg et al 2009;Jönsson et al 2009;Finstad et al 2010) and altitudinal gradients (Tracy 1999;Takahashi and Pauley 2010). Other factors that affect energy allocation include body size (Deegan 1986;Henderson et al 1988;Heulett et al 1995;Lampo and Medialdea 1996;Post and Parkinson 2001;Scott et al 2007), life history Jonsson 1998, 2003;Rikardsen and Elliott 2000;Morgan et al 2002), and food availability and quality (Heulett et al 1995;Garvey and Marschall 2003;Sogard and Spencer 2004;Borcherding et al 2007).…”