Tolerance of Whitefish (Coregonus Lavaretus) Early Life Stages to Manganese Sulfate is Affected by the Parents

Abstract

European whitefish (Coregonus lavaretus) embryos and larvae were exposed to 6 different manganese sulfate (MnSO4) concentrations from fertilization to the 3-d-old larvae. The fertilization success, offspring survival, larval growth, yolk consumption, embryonic and larval Mn tissue concentrations, and transcript levels of detoxification-related genes were measured in the long-term incubation. A full factorial breeding design (4 females × 2 males) allowed examination of the significance of both female and male effects, as well as female–male interactions in conjunction with the MnSO4 exposure in terms of the observed endpoints. The MnSO4 exposure reduced the survival of the whitefish early life stages. The offspring MnSO4 tolerance also was affected by the female parent, and the female-specific mean lethal concentrations (LC50s) varied from 42.0 mg MnSO4/L to 84.6 mg MnSO4/L. The larval yolk consumption seemed slightly inhibited at the exposure concentration of 41.8 mg MnSO4/L. The MnSO4 exposure caused a significant induction of metallothionein-A (mt-a) and metallothionein-B (mt-b) in the 3-d-old larvae, and at the exposure concentration of 41.8 mg MnSO4/L the mean larval mt-a and mt-b expressions were 47.5% and 56.6% higher, respectively, than at the control treatment. These results illustrate that whitefish reproduction can be impaired in waterbodies that receive Mn and SO4 in concentrations substantially above the typical levels in boreal freshwaters, but the offspring tolerance can be significantly affected by the parents and in particular the female parent.