Eastern Indian Ocean Blue Whale Migratory Route IMMA

Size in Square Kilometres

1,101,394 km2

Qualifying Species and Criteria

Pygmy blue whale – Balaenoptera musculus brevicauda

Criterion A; C (ii, iii)

Marine Mammal Diversity 

Balaenoptera musculus intermedia


Within this area pygmy blue whales migrate from one of their known foraging grounds reported in the published literature: the Perth Canyon and surrounds (from the Houtman Abrolhos Islands down to the very south of WA) (Rennie et al., 2009). The Perth canyon promotes localised upwelling, enhancing productivity and allowing plankton to bloom and thus attracting the whales (Rennie et al., 2009). The Perth Canyon is thought to be used by both pygmy blue and Antarctic blue whales for feeding (Commonwealth of Australia, 2015), but published evidence of the latter is lacking. Evidence of feeding pygmy blue whales comes from the analysis of the movement behaviour of pygmy blue whales tagged at Perth Canyon where milling behaviour was identified, and high levels of occupancy occurred in Perth Canyon/Naturalist Plateau and also Ningaloo Reef.

Pygmy blue whales are income breeders and are thus adapted to exploit widely dispersed and ephemeral food sources. Given this, they likely feed at many points along their migratory path and that is why we combine the migration and foraging of pygmy blue whales in this IMMA.This area is based on the Australian Biologically Important Area (BIA) for migration designated by the Australian Government’s Conservation Values Atlas (CVA) for the pygmy blue whale migration route (http://www.environment.gov.au/webgis-framework/apps/ncva/ncva.jsf) and adds an area to the west and north-west based on the migratory movements of tagged whales (Double et al., 2014) and the finding by McCauley (2011), that only 6-40% of pygmy blue whales which pass by the northern end of the Monte Bello Islands were estimated to pass by Scott Reef, suggesting many pygmy blue whales may also migrate further west of the shelf edge. In addition, it also includes the Exmouth Plateau as acoustic data collected in this area found that pygmy blue whales travel up to 400 km from shore (Gavrilov et al., 2018). The IMMA also includes Geographe Bay, in southern Western Australia, as relatively large numbers (~450 in ~25 d survey) of pygmy blue whales with calves (and potentially Antarctic blue whales) use Geographe Bay and the Naturaliste Plateau as a narrow transit corridor (Recalde-Salas et al., 2014, Salgado-Kent et al., 2014).

Description of Qualifying Criteria

Criterion A – Species or Population Vulnerability

The total eastern Indian Ocean blue whale population was estimated at 662-1559 in 2010 (McCauley and Jenner, 2010). Blue whales are Red Listed by the IUCN as Endangered (EN) though the pygmy blue whale (Balaenoptera musculus brevicauda subspecies) has not yet been evaluated (dx.doi.org/10.2305/IUCN.UK.2018-2.RLTS.T2477A156923585.en).

Criterion C: Key Life Cycle Activities

Sub-criterion Cii: Feeding Areas

The application of time in area spatial analysis of satellite tracking data from pygmy blue whales from the Perth Canyon (Double et al., 2014) show areas of high occupancy along and within the migratory path. Lunge feeding behaviour was recorded by a lander tag which recorded dive data as well as location data (Owen et al., 2016). Double et al. (2014) identify Perth Canyon/Naturalist Plateau and also Ningaloo Reef as the main regions of high occupancy. Areas where animals have high occupancy are usually considered important and are often indicative of foraging behaviour (Kareiva and Odell, 1987) but also resting and breeding (Bailey et al., 2009). It was suggested that the high occupancy reported at Ningaloo Reef may be attributed to the fact that the whales were following the shelf as it narrows around North-West Cape area (Double et al., 2014), however the fact that milling was also reported (Double et al., 2014) and that lunge feeding behaviour is commonly observed in this area (Michele Thums, Curt Jenner, Tiffany Klein pers comm), suggests that Ningaloo is in fact a feeding area. The Australian Government’s Conservation Management Plan for Blue Whales identifies the Perth Canyon/Naturaliste Plateau as “known foraging” and the area off Exmouth (Ningaloo) and Scott Reef as “Possible Foraging” areas which are protected under the Environment Protection and Biodiversity Conservation (EPBC) Act 1999, (Commonwealth of Australia, 2015). All these areas are considered “known foraging” in the Australian Government’s CVA (Figure 1), although not defined under the EPBC Act. Although there are anecdotal reports of pygmy blue whales feeding at Scott Reef, no published evidence could be found. But note that the IMMA encompasses all the known and possible foraging areas identified by the Australian Government and CVA and others that might be used by pygmy blue whales along their migration. The identified foraging areas can be considered important to the survival of blue whales as they seasonally support highly productive ecosystem processes on which significant aggregations of whales rely (Commonwealth of Australia, 2015). Antarctic blue whale calls have also been recorded in the Perth Canyon (Balcazar et al., 2015) but use of the Canyon by the species is not well documented.

Sub-criterion Ciii: Migration Routes

Satellite tracking data from pygmy blue whales consisting of 11 tagged in the Perth Canyon, Western Australia (Double et al., 2014), 13 tagged in the Bonney Upwelling, South Australia (Moller et al., 2015), one of which migrated along the WA coast, 1 tagged 35 km north of the Perth Canyon (Owen et al., 2016) and 1 tagged at NW Cape (AMS, 2009) have identified the area from the southern tip of Australia up to the Banda and Molucca Seas as the migratory pathway of pygmy blue whales.

Supporting Information

AIMS. 2009. North West Shoals To Shore Research Program. Australian Institute of Marine Science, December 2019. 4pp.

Bailey, H., Mate, B., Palacios, D. M., Irvine, L., Bograd, S. J. & Costa, D. P. 2009. Behavioural Estimation Of Blue Whale Movements In The Northeast Pacific From State-Space Model Analysis Of Satellite Tracks. Endangered Species Research, 10, 93-106.

Balcazar, N. E., Tripovich, J. S., Klinck, H., Nieukirk, S. L., Mellinger, D. K., Dziak, R. P. & Rogers, T. L. 2015. Calls Reveal Population Structure Of Blue Whales Across The Southeast Indian Ocean And The Southwest Pacific Ocean. Journal Of Mammalogy, 96, 1184-1193.

Commonwealth Of Australia 2015. Conservation Management Plan For The Blue Whale – A Recovery Plan Under The Environment Protection And Biodiversity Conservation Act 1999.

Double, M. C., Andrews-Goff, V., Jenner, K. C. S., Jenner, M.-N., Laverick, S. M., Branch, T. A. & Gales, N. J. 2014. Migratory Movements Of Pygmy Blue Whales (Balaenoptera Musculus Brevicauda) Between Australia And Indonesia As Revealed By Satellite Telemetry. Plos One, 9, E93578.

Gavrilov, A., Mccauley, R., Paskos, G. & Goncharov, A. 2018. Southbound Migration Corridor Of Pygmy Blue Whales Off The Northwest Coast Of Australia Based On Data From Ocean Bottom Seismographs. The Journal Of The Acoustical Society Of America, 144, El281-El285.

Kareiva, P. & Odell, G. 1987. Swarms Of Predators Exhibit Prey Taxis If Individual Predators Use Area-Restricted Search. American Naturalist, 130, 233-270.

Mccauley, R. 2011. Woodside Kimberley Sea Noise Logger Program, September 2006 To June 2009: Whales, Fish And Man Made Noise. Report To Woodside.

Mccauley, R. & Jenner, K. 2010. Migratory Patterns And Estimated Population Size Of Pygmy Blue Whales (Balaenoptera Musculus Brevicauda) Traversing The Western Australian Coast Based On ….

Moller, L., Attard, C., Double, M. C., Paton, D. & Bilgmann, K. 2015. Satellite Tagging Of Blue Whales In Southern Australian Waters: Examining Movements And Occupancy Patterns To Inform Management Decision-Making. Australian Marine Mammal Centre Final Report.

Owen, K., Jenner, C. S., Jenner, M.-N. M. & Andrews, R. D. 2016. A Week In The Life Of A Pygmy Blue Whale: Migratory Dive Depth Overlaps With Large Vessel Drafts. Animal Biotelemetry, 4, 17.

Recalde-Salas, A., Salgado Kent, C. P., Parsons, M. J., Marley, S. A. & Mccauley, R. D. 2014. Non-Song Vocalizations Of Pygmy Blue Whales In Geographe Bay, Western Australia. J Acoust Soc Am, 135, El213-8.

Rennie, S., Hanson, C. E., Mccauley, R. D., Pattiaratchi, C., Burton, C., Bannister, J., Jenner, C. & Jenner, M. N. 2009. Physical Properties And Processes In The Perth Canyon, Western Australia: Links To Water Column Production And Seasonal Pygmy Blue Whale Abundance. Journal Of Marine Systems, 77, 21-44.

Salgado-Kent, C. P., Burton, C., Recalde-Salas, A., Marley, S. & Kniest, E. 2014. Defining The Significance Of Resting And Migratory Areas In A Key Habitat In Australia’s Southwest For Baleen Whales. Project Centre For Marine Science And Technology 1199. Presented To Ifaw. 58 Pp.


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