Burbot (Lota lota L.) in Lake Constance change their habitat several times during ontogeny. The adults live in the cold profundal zone and spawn in winter from January to March. The larvae hatch at the end of April, first ascend to the pelagial and then, in August of the same year, migrate into littoral habitats. Based on analyses of otolith microstructure it has been suggested that the migration of the pelagic larvae to the littoral does not take place through the warm epilimnion, as observed in other fish species, but rather through cold, hypolimnetic water layers. The aim of this study is to test this hypothesis by a horizontally and vertically stratified sampling of larvae in the pelagic zone, combined with a growth analysis of the larvae caught at different depths and distances from the shore.
