Marine biologists from The University of Western Australia have recommended protection measures for a humpback whale nursery ground in the Exmouth Gulf in Western Australia’s Pilbara region.

Dr Kate Sprogis, from UWA’s Oceans Institute and School of Biological Sciences, was lead author of the paper published in the Australian Journal of Zoology. 

“Humpback whales migrate from their Antarctic feeding grounds to their north-west Australian breeding grounds,” Dr Sprogis said.

“Nursery areas, such Exmouth Gulf, are important for lactating humpback whale mothers, as they carry the highest energy demands in the population.”

The study examined a long-term aerial survey dataset from flights conducted from 2000 to 2010 across the North West Cape, Pilbara coast and Exmouth Gulf in north-western WA.

Analysis of the aerial data found the largest density hotspot of humpback whales was in the Exmouth Gulf.

“The highest encounter rate of mother and calf pairs was in October in Exmouth Gulf, and this was significantly higher compared to the North West Cape and Pilbara coast,” Dr Sprogis said.

“The comparison of the three regions confirms and quantifies Exmouth Gulf as an important nursery area for humpback whales.”

The study helps inform conservation plans so nursery areas can remain relatively undisturbed from human pressures, allowing mothers to rest, conserve energy and nurse their young.

“The humpback whale high-density area on the western side of Exmouth Gulf is of importance as the waters are shallow,” Dr Sprogis said.

“If there is further industrialisation in these shallow waters, such as a deep-water port,  there will be an increase in underwater noise from ships and boats and more chances of ship strikes on whales.”