"It was really special, the only way I can describe it is like when a cat offers you a mouse," she says.
Eisert has spent this Antarctic season studying Type-C killer whales in order to gain an understanding of how many there are in the region, where they live and what they eat.
Her research focuses on the Ross Sea region Marine Protected Area, and how the whales would be affected by a change in toothfish availability due to fishing.
The moment was made all the more poignant for her because of this.
"Here I am carrying out research to help protect the Ross Sea region and find out whether or not the whales eat toothfish, and one comes up showing me it does.
"Whales are highly social and there has been an instance in the past where a leopard seal offered a diver a penguin, but I've never had an experience quite like this," she says.
The research is supported by Antarctica New Zealand and the Pew Charitable Trust through a Marine Conservation Fellowship to Regina Eisert.