Plasticity in digestion capacity of Perch
(Perca fluviatilis)
by
Celine Colson
Eurasian perch (Perca fluviatilis) have different phenotypes according to the habitat in
which they live. The habitat specific differences in morphology of perch are related to
differences in different foraging capacities. If perch are adapted to mainly capture and
handle one type of food resource then they might also have more efficient enzymes to
digest those particular food resources. Therefore, we examined the effect of different
diets on the digestive physiology of perch. This question was evaluated in a 2x2 full
factorial design experimental set-up with 4 replicates. Some perch were raised on a diet
of Artemia brine shrimps and the others with chironomid larvae during 5 months. After
3 weeks of acclimatization in the aquaria, half of the fish were fed with the other food
resource. After feeding and a digestion period, the stomachs were flushed and their
contents weighed in order to determine the amount of digested food. The experiment
was repeated 3 times. The statistical analysis (two-way ANOVA) showed that neither
the population nor the food had an effect on the proportion of digested food. Thus,
perch did not show any adaptations to improve digestion of a certain food resource over
the 5 months rearing period.
Undergraduate Thesis in Biology, 10 p (15 ECTS), spring 2004
Evolutionary Biology Centre
Department of Limnology
Supervisor: Peter Eklöv