Posted on 11/06/2015 by Phillip Island Nature Parks

Unravelling the mystery of the penguin reproductive cycle

Understanding how marine animals respond to environmental changes is crucial in marine studies, especially in the face of challenges such as climate change. But animals can be affected by environmental changes at local, regional or global scales. Searching for the right scale is the Holy Grail in the marine ecosystem.

In a new approach, researchers from Spain’s Doñana National Park and Phillip Island Nature Parks used continuous high-temporal resolution satellite data on ocean currents, chlorophyll levels and sea surface temperatures to examine the relationship between patterns in marine productivity and penguin egg-laying dates over 19 years (1993–2011), according to exciting new research published this week in the Proceedings of the Royal Society London.

Recent approaches based on circuit-theory allowed the researchers to trace water flow to little penguin foraging range. This information was then matched with data on chlorophyll-a levels and sea surface temperatures to determine the environmental conditions which would trigger the penguins’ breeding cycle. 

“We discovered that across these years, the levels of chlorophyll (an indicator of marine productivity and hence food availability) reached their peak approximately seven weeks after the sea surface temperatures had reached their lowest point. Phillip Island’s Little penguins are so highly attuned to changes in their marine environment, they are able to “read” these environmental cues to match their annual breeding to annual peaks in food availability”, explains Isabel Afán, Spanish researcher and the senior author of the paper. 

“This new approach also provides a new framework for researchers around the world to find out the right scale of environmental variables, enabling a much greater understanding of the effect of environmental changes on animals within a marine environment”, concludes Dr André Chiaradia, penguin biologist at the Phillip Island Nature Parks and one of the co-authors on this paper