| Abstract: | Pollan alevins and fry were collected in the open lake between March and July. Fish were measured in total length, upper (Uj) and lower (Lj) jaws and weighed. The gape-height was calculated according to two different formulae. For the examined fish the relationship between total length (Lt) and gape-height (D) was found to be D=0.092 Lt—0.306. The size of food in the gut content was measured, and this increased during fish growth, but amounted to 13.2–26.0 % of D. In the first food of pollan alevins, nauplii and copepodites dominated, but after the alevins had reached 20 mg, copepods appeared to be more frequent food items. In the middle of May, Daphnia longispina was found in the food of pollan fry with an individual weight over 45 mg. Benthic invertebrate fauna were taken after the fish weighed more than 1.4 g. Chironomus anthracinus and Chironomus sp. larvae were among the food item dominants. |
