The effect of temperature on embryonic and yolk-sac larval development in the burbot Lota lota

The present study investigated the effect of various temperature regimes on embryonic and yolk-sac larval development of the burbot Lota lota. At constant temperature regimes a high percentage of ready-to-hatch embryos, hatched larvae and normally shaped larvae was observed at the lowest temperature (2° C), which significantly decreased with increasing temperatures (4 and 6° C). No larvae hatched at 9° C. The stream temperature regime had no effect on the percentage of ready-to-hatch embryos, but significantly decreased the percentage of hatched larvae and of normally shaped larvae. The lake temperature regime did not affect the viability variables. Also an abrupt temperature increase from 2 to 4° C after 8 days and from 2 to 9° C after 48 days had no effect on the evaluated viability variables. For yolk-sac larvae no temperature related mortalities or abnormalities were observed between 2 and 9° C.