A scientist from Nelson spent Christmas in Antarctica in order to understand what effects climate change and commercial fishing have on the continent's top predators.
Cawthron Institute senior scientist Jonathan Banks is studying the diets of killer whales, Weddell seals and penguins.
He and his team visited seal and penguin colonies, collecting their faecal matter, from which DNA was extracted and brought back to Nelson for analysis.
Dr Banks says it's a collaborative effort.
"People who are good at maths will be able to model the nutritional value of the food, what they're exactly eating and from that we can work out what effects climate change or increased fishing pressure or any of those other factors that effect the prey will have on the seals."
Dr Banks works with councils throughout New Zealand identifying faecal contamination in marine and freshwater environments.
He says his methods are so precise that, through DNA testing, he is able to trace the source of contamination to the species responsible.