Forms of whitefish, Coregonus lavaretus (L.) in Lake Miedwie

Abstract

The whitefish (Coregonus lavaretus) of the Lake Miedwie was studied. Based on gill raker counts, three f onns of the species are discerned: lavaretus, maraena, and generosus. The maraena fonn individuals showed the highest growth rate. The other two forms grew more slowly, their growth rates being similar to each other. The maraena andgenerosus fonns fed on both plankton and benthos, while lavaretus consumed betnhos only;

Food selection of Coregonus lavaretus in a brackish water ecosystem

“…The present study supports results of previous investigations, indicating that the diet of benthic C. lavaretus is dominated by macrozoobenthos, but differences in consumption of different food taxa were found. Most studies suggest that in the freshwater lakes of the Baltic Sea basin the food choice of C. lavaretus shows little selectivity and fishes can adapt their diet in relation to the availability of different food taxa (Hessen et al , 1986; Svärdson et al , 1988; Trzebiatowski et al , 1988; Miinalainen & Heikinheimo, 1998; Kahilainen et al , 2004; Kahilainen & Østbye, 2006). In warmer Polish and Belgian lakes, C. lavaretus shows a broader diet spectrum (Trzebiatowski et al , 1988; Malbrouck et al , 2005).…”

“…Most studies suggest that in the freshwater lakes of the Baltic Sea basin the food choice of C. lavaretus shows little selectivity and fishes can adapt their diet in relation to the availability of different food taxa (Hessen et al , 1986; Svärdson et al , 1988; Trzebiatowski et al , 1988; Miinalainen & Heikinheimo, 1998; Kahilainen et al , 2004; Kahilainen & Østbye, 2006). In warmer Polish and Belgian lakes, C. lavaretus shows a broader diet spectrum (Trzebiatowski et al , 1988; Malbrouck et al , 2005). The most important food items have been shown to be insect larvae and molluscs and to a lesser extent benthic cladocerans, ostracods, isopods, gammarid amphipods, fishes, fish eggs and surface insects (Hessen et al , 1986; Svärdson et al , 1988; Trzebiatowski et al , 1988; Tolonen, 1997; Miinalainen & Heikinheimo, 1998; Kahilainen et al , 2004; Malbrouck et al , 2005; Kahilainen & Østbye, 2006).…”

“…In warmer Polish and Belgian lakes, C. lavaretus shows a broader diet spectrum (Trzebiatowski et al , 1988; Malbrouck et al , 2005). The most important food items have been shown to be insect larvae and molluscs and to a lesser extent benthic cladocerans, ostracods, isopods, gammarid amphipods, fishes, fish eggs and surface insects (Hessen et al , 1986; Svärdson et al , 1988; Trzebiatowski et al , 1988; Tolonen, 1997; Miinalainen & Heikinheimo, 1998; Kahilainen et al , 2004; Malbrouck et al , 2005; Kahilainen & Østbye, 2006).…”

Zoosporic fungi growing on the eggs of Coregonus lavaretus maraena (Bloch, 1779) from Lake Miedwie in Pomerania

“…According to our recent studies, bottom crustaceans and shellfish, both in cluded in the food ofwhitefish (G3c. sowska 1965;Trzebiatowski et al 1988), are vectors of parasitic zoosporic fungi for fish. Such three dangerous species as Saprolegnia delica, Sap rolegnia ferro;; and Saprolegnia parasitica, causing great fish losses, can be found on Asellus aquaticus, Pallasiola quadrispinosa and on the three species of the genus Gamma rus examined (Czeczuga et al 1999).…”

“…Moreover, Heese (1992) describes peipus whitefish (C. lavaretus maraenoides (Poljakow, 1874)) from Goldapiwo Lake in Masuria, which according to some investigators is a subspecies of the noble whitefish (Falkowski 1992;Szczerbowski 1993). As hydrochemical conditions deteriorated in the 80s the Miedwie whitefish was thought to be extinct in Lake Miedwie (Trzebiatowski et al 1988;Heese 1990). However, in the 90s the water purity in this lake improved and the autochtonic population of the whitefish was restored (Pietrucha 1999).…”