R. A. Dunlop, M. J. Noad, D. H. Cato, and D. Stokes, “, The social vocalization repertoire of east Australian migrating humpback whales (, 9. You have to find your whale first. Within a season the Portland site did not show consistency of EIO PB whale presence or number of calling individuals, but when the number of calling individuals was integrated across a season and correlated with an upwelling index of seasonally integrated seabed water temperature across seven seasons, the upwelling index predicted 83% of the seasonal variance in whale presence. The reason the whales come to this area from February to April is for the great seafood. Project manager Dr Rob McCauley says these mysterious calls are too low for the human ear and need to be sped up four times to become audible. This nutrient rich water provides food for millions of krill, the perfect summer snack for whales.

(Source: Centre for Whale Research (WA)). B. Wursig, E. M. Dorsey, M. A. Fraker, R. S. Payne, and W. J. Richardson, “, K. M. Stafford, E. Chapp, D. R. Bohnenstiel, and M. Tolstoy, “, A. N. Gavrilov, R. D. McCauley, C. Salgado Kent, J. Tripovich, and C. Burton, “, E. M. Oleson, J. Calambokidis, W. C. Burguess, M. A. McDonald, C. A. LeDuc, and J. Scientists estimate up to 100 whales come to feed here between December and May each year, and that number seems to be growing. One favourite feeding area is the Rottnest Trench, a huge 1300 metre deep canyon cut into the edge of the continental shelf off south west Western Australia. What's amazing about the pygmy blue whale is how much researchers DON'T know about this mammal. The Jenners are also taking biopsy samples of whale skin, by shooting a small hollow arrow into the blubber to collect tissue. The question now, is, with such a history, will the population recover? One technique is to monitor the calls of pygmy blue whales. "Last year when we were out there, I felt like I was walking through the forest, and I was sniffing the air, I was looking at the leaves, I was looking for a bear that had walked through the forest and I was looking for it's spoor, where it had stood, where it had bent the leaves, where it had weed — we were trying to look for any clues as to why it was here, what it was doing here, how long it was staying here.". A. Hildebrand, “, Behavioral context of call production by eastern North Pacific blue whales, 4.

Passive acoustic recorders set around Australia since 2004 have been used to study blue whales. The pygmy blue whale song type is variable with different song types or perhaps "dialects" produced by geographically separated "sub-populations".

Ljungblad et al., 1997, Ljungblad et al., 1998 were the first to differentiate the "z" shaped call of the Antarctic blue whale from the Indian Ocean pygmy blue whale … The EIO PB shows three migratory stages: "southbound" from November to January during which whales travel down the Western Australian coast; "southern Australian" where animals spread across the Indian and Southern Oceans spanning longitudes from 74° to 146° E down to at least a latitude of 55° S searching for food and feeding; then a northern migration where they return north to Indonesian waters post April-August.

But are these numbers increasing? A. N. Gavrilov, R. D. McCauley, C. Salgado Kent, J. Tripovich, and C. Burton, “, Vocal characteristics of pygmy blue whales and their change over time, 3. Passive acoustic recorders set around Australia since 2004 have been used to study blue whales.

E. M. Oleson, S. M. Wiggins, and J. The Jenners are working with the WA Museum, Curtin University, and the University of WA on a whale project funded by the Department of Defence. "They make a very long moan — there are three different types of sound, which is structured into a song about 120 seconds long, which is then repeated every few minutes for up to six hours. A “provisional” estimate of 10,000 pygmy blue whales existed prior to 1961; however, as the species have been extensively hunted since then, their actual population size is impossible to determine.