Satellite tagging of pygmy blue whales off Western Australian has for the first time identified their 10,000 km migratory route to Indonesia and back.
Mike Double, Australian Antarctic Division marine mammal scientist, says the information could be used in a precautionary way to identify and manage risks such as vessel traffic, oil and gas field locations and increased ambient noise from development, shipping and fishing.
“This is particularly important, as pygmy blue whales were targeted by commercial and illegal whalers prior to the moratorium on whaling (1986), and we don’t know if the population has recovered subsequently,” Dr Double said.
Eleven pygmy blue whales were tagged in April 2009 and March 2011 within the Perth Canyon off the coast of Western Australia.
The tags transmitted to the Argos satellite system from between eight and 308 days. All the whales travelled north after tagging, except one, which remained in the tagging location for eight days before its tag failed.
Throughout the tracking period, each whale covered some 3,000 km, moving about 22 km per day.
The tagged whales travelled within about 100 km of the coastline throughout March and April,until they reached the North West Cape peninsula, about 1200 km from the Perth Canyon.
By June they were travelling through the Savu and Timor seas.
They stopped within the Banda and Molucca seas, just south of the equator, and remained there until September.
This timing suggests these seas are important feeding and calving grounds.
One tag continued to transmit intermittent location information in December and February by which time the whale had migrated to a region south of the Great Australian Bight.
Pygmy blue whales reach about 24 metres in length and are slightly smaller than their Antarctic blue whale cousins which grow to about 31 metres.
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