The Little Penguin (Eudyptula minor) as an effective and accurate indicator of coastal trace metal pollution

A better understanding of the toxicology of the St Kilda Little Penguin (Eudyptula minor) population is important for the management and conservation of the species while also providing valuable insights into the health of... [ view full abstract ]

A better understanding of the toxicology of the St Kilda Little Penguin (Eudyptula minor) population is important for the management and conservation of the species while also providing valuable insights into the health of Port Phillip Bay - a semi-enclosed ecosystem impacted by industrial run-offs, dredge works and commercial fishing. We conducted a comprehensive, non-destructive sampling program over three years (blood, feathers and faeces) to determine the trace metal body burden of this resident urban top predator, as well as of conspecifics at less industrialised settings, and investigated the factors determining long- and short-term variation in trace metal concentrations. Colony location had the most significant effect on trace metal concentrations in the blood and feathers of adult Little Penguins. In particular, the non-essential metals arsenic, mercury and lead followed a distinct pollution gradient. While we found significant differences between sexes for some trace metals at some locations and over some sampling periods; overall, sex had no significant multivariate effect on penguin trace metal concentrations. Blood mercury levels showed an increasing annual trend at St Kilda, while decreasing at Phillip Island over the same time period. Trace metal concentrations in feathers were largely within safe limits. As this is the first study of trace metals in the blood of any penguin species, and few adverse-effect-levels have been established for metals in other seabirds, the potential impacts on a population level are yet to be established. To date there is no evidence of any colony-level deleterious effects of the increased contaminant load at St Kilda. However, in light of the patterns detected by this study, we recommend more detailed coordinated monitoring of the St Kilda and Phillip Island populations. Based on this research, we advocate that the Little Penguin may be utilised as an effective and accurate indicator of coastal trace metal pollution, which will also aid the management and conservation of this iconic species at St Kilda in particular.