No relationship between gastrointestinal parasite intensities or mercury burdens on fluctuating asymmetry in Common Eider (Somateria mollissima) mandibles

Abstract

Mercury (Hg) emissions have increased since 1950 and biomagnification in Arctic ecosystems can affect animals, particularly at higher trophic levels. Exposure to Hg can negatively affect young developing animals, resulting in altered morphology and ultimately, lower fitness. We examined the relationship of mandible fluctuating asymmetry (FA) with gastrointestinal helminth intensity and breast muscle Hg concentration in Common Eider (Somateria mollissima borealis). Procrustes analysis of variance indicated significant FA but relatively high measurement error. Based on multiple linear regression modelling, there was no significant relationship between FA and Hg concentration or parasite burden. There may be a mismatch in trying to relate amount of Hg and parasite intensity in adults to FA that would have occurred early in life during skeletal development.