Abstract:

Recent evidence suggests that offspring viability is related to maternal characteristics in fishes, possibly because ova quality is dependent upon these maternal traits. Provisioning of ova with particular constituents may vary with the age, size, and current condition of the female. We examined patterns of within- and among-population variation in ova concentrations of seven essential metals (Ca, Co, Cu, Fe, Mg, Mn, Zn) in four walleye (Sander vitreus) and one lake whitefish (Coregonus clupeaformis) populations. Within populations, among-female variability in ova metal concentrations was lowest for Zn (CVs 6.2-11%), and highest for Mn (CVs 26-88%). However, ova metal concentrations were not consistently related to maternal age, size, or indices of body condition. Mean ova metal concentrations varied significantly among walleye populations for five of the seven metals examined; variability was lowest for Ca and Co, and highest for Mg and Mn. Walleye and lake whitefish from the same waterbody, Lake Ontario, also differed significantly in ova metal concentrations. Lake whitefish produced ova with significantly higher concentrations of Ca, Fe, Mn, and Zn. Ova metal concentrations observed in this study were generally lower than those reported in earlier studies. Metal provisioning of ova in walleye and lake whitefish does not appear to be related to the ontogenetic or nutritional state of the female.

Notes:

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