DOI: 10.5061/dryad.7ts26
title: Data from: Multiple stressors in a top predator seabird: potential ecological consequences of environmental contaminants, population health and breeding conditions

description: Environmental contaminants may have impacts on reproduction and survival
 in wildlife populations suffering from multiple stressors. This study
 examined whether adverse effects of persistent organic pollutants (POPs)
 increased with poor population health and breeding conditions in three
 colonies (60–74°N) of great skua (Stercorarius skua) in the north-eastern
 Atlantic (Shetland, Iceland and Bjørnøya [Bear Island]). POPs
 (organochlorines [OCs] and polybrominated diphenyl ethers [BDEs]) were
 measured in plasma of incubating birds (n = 222), concentrations differing
 nearly tenfold among colonies: Bjørnøya (2009) &gt; Bjørnøya (2010)
 &gt; Iceland (2009) &gt; Shetland (2009). Reproductive success
 (hatching success and chick survival) showed that breeding conditions were
 favourable in Shetland and at Bjørnøya (2010), but were very poor in
 Iceland and at Bjørnøya (2009). Biomarkers indicated that health was poor
 in the Shetland population compared to the other populations. Females
 whose chicks hatched late had high POP concentrations in all colonies
 except at Bjørnøya (2010), and females losing their eggs at Bjørnøya
 (2009) tended to have higher concentrations than those hatching. Moreover,
 there was a negative relationship between female POP concentrations and
 chick body condition at hatching in Iceland and at Bjørnøya (2010).
 Supplementary feeding experiments were conducted, and in Iceland where
 feeding conditions were poor, significant negative relationships were
 found between female POP concentrations and daily growth-rate in
 first-hatched chicks of control nests, but not in food supplemented nests.
 This suggests that negative impacts of POPs were mitigated by improved
 feeding conditions. For second-chicks, there was a strong negative
 relationship between the female POP concentrations and growth-rate, but no
 effects of supplementary feeding. Lowered adult return-rate between
 breeding seasons with increasing POP loads were found both at Bjørnøya
 (2009) and in Shetland, especially related to BDEs. This indicates
 stronger fitness consequences of POPs following seasons with very poor
 breeding conditions and/or high reproductive effort. This study suggests
 that the impacts of POPs may differ depending on population health and
 breeding conditions, and that even low concentrations of POPs could have
 ecological consequences during adverse circumstances. This is important
 with regard to risk assessment of biomagnifying contaminants in marine
 ecosystems.
description: Data from: Multiple
 stressors in a top predator seabird: potential ecological consequences of
 environmental contaminants, population health and breeding
 conditionsThe file contains data
 on individual female (F) and male (M) great skuas from different colonies
 in the Northeast Atlantic: Shetland (S), Iceland (I) and Bjørnøya (Bear
 Island, BI). The file includes measures on reproductive performance
 (hatching date, chick hatching condition and chick growth) in females, and
 return rate between years for both sexes. Individual levels of pollutants
 are also included.FileSKUA PLOS
 One.csv