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A Whale of a time!

A Whale of a time!

    Whales of Victoria

    There are about 90 identified species of Cetacea (whales, dolphins and porpoises) that exist worldwide, with 31 of these species recorded in Victorian coastal areas (Foord et al. 2019). That is, roughly one third of the world’s Cetacea species live in or migrate to Victorian waters, an excellent indication of the health of our local oceanic environments as well as the abundant biodiversity supported by these ecosystems. 

    There are two types of whales, toothed (Odoncetes) and baleen (Mystectes) whales. Confusingly, dolphins and porpoises also fall under the general category of ‘toothed whales’.

    Whales have a variety of important roles within ocean ecosystems, including regulating the flow of food availability, as well as maintaining  stable food chains by regulating prey species population numbers and preventing overpopulation. 

    Whale carcasses create localised ecosystems for deep sea species, namely scavengers and opportunists, with a potential to feed organisms for up to 100 years! The colder temperatures on the seafloor allow the carcass to decompose at a slower rate than at the ocean surface, providing a number of deep-sea species with food. 

    In Victoria, the most common species of whale to frequent our waters throughout the migration period from May to October are the humpback and southern right whales, which are both types of baleen whales, named for the long plates of baleen, sometimes referred to as “whalebone”, that hang from their upper jaw in place of teeth (Bannister 2009). Baleen plates are made from keratin, the same substance our hair and nails are made from (Szewciw et al. 2010)! These plates are used for straining out plankton/krill caught in large gulps of water.

    Humpback whale (Megaptera novaeangliae)

    The humpback whale has become an iconic symbol of the whale migration season here in Victoria. Known for its acrobatic prowess, humpback whales attract people from around the world to witness their incredible displays. 

    Southern hemisphere humpback whales have been known to travel more than 16,000 km annually (Shirihai & Jarrett 2006), making the journey one of the longest migrations of any mammal in the world. Humpback whales can be found all around the world, can weigh between 24-40 tonnes, and grow between 11-18m long, depending on their subpopulation (where in the world they are found), with females being around 1.5m longer than the males (Shirihai & Jarrett 2006).

    Humpback whales have long, arm-like pectoral fins that are unique to the species (Shirihai & Jarrett 2006). They have a grey to black colouration on their back, with southern-hemisphere populations having varied patterns of white on their underbelly (Shirihai & Jarrett 2006). Humpbacks also have distinctive pleats on their throats which allow the whale to open their mouths wide to gulp in the water and prey items (Simon et al. 2012). They are renowned for their aerial displays, both for their beauty and their danger; human deaths have been recorded from humpback whale breaches landing on vessels and killing those on board (Shirihai & Jarrett 2006). 

    To identify individual humpback whales, scientists use the patterning on the underside of their often barnacle-clad tail flukes, as well as the shape of the dorsal fin and small hump in front of their dorsal fin, to differentiate between animals (Shirihai & Jarrett 2006).  

    This species migrates annually from summer feeding grounds near both the North and South poles to warmer waters closer to the equator to breed in the winter. In the case of the populations that migrate along the east coast of Australia, summer feeding grounds are found in the waters surrounding Antarctica, and winter breeding grounds are found in the waters off the coast of Queensland (Rock et al. 2006). Luckily for those of use that live around Port Phillip Bay, humpbacks can be seen in the Bay during the migration period.  

    When looking out for humpbacks, it is easy to distinguish them from other whale species due to their small, bushy blow (vapour that is expelled out of the blowhole) which can reach up to 3m in height (Shirihai & Jarrett 2006). 

    Southern right whale (Eubalaena australis)

    Southern right whales are typically distinguished by the white growths on their head known as callosities (Shirihai & Jarrett 2006). These are simply thickened pieces of skin that arise from repeated contact and friction. These growths are in fact perfect for identification, as each individual possesses a unique arrangement of them (Shirihai & Jarrett 2006)

    These whales weigh around 80 tonnes and can grow up to 17m in length (Shirihai & Jarrett 2006)! They lack a dorsal fin and are quite bulky in their shape, with a rotund body and a strongly arched mouth line (Shirihai & Jarrett 2006). Southern right’s are generally dark in colour, including shades of black, dark brown, dark blue and mottled grey, with irregular white blotches on their bellies (Shirihai & Jarrett 2006). Like the humpback, they use baleen plates to trap krill for filter feeding (Shirihai & Jarrett 2006)

    Southern right whales spend the summer months in the cold waters of the Antarctic and the mid-Southern Ocean (Shirihai & Jarrett 2006). As the winter breeding season approaches, they migrate to more temperate waters off the coast of Australia (Shirihai & Jarrett 2006). They are found in the southern hemisphere, frequenting Australia, New Zealand, South American, South Africa, and some smaller islands (Shirihai & Jarrett 2006)

    Southern right’s are famously playful and are notorious for being easily identifiable both due to their distinctive shape and their inquisitive, often approachable, nature (Shirihai & Jarrett 2006). They produce an often asymmetrical V-shaped blow that can reach 5m in height, and are often observed performing acrobatics or interacting with other pinnipeds or smaller cetaceans (Shirihai & Jarrett 2006). 

    Report a sighting via trakMM

    Whilst we would love to be on the water all the time, it’s unfortunately not possible. MMFs trakMM initiative allows the community using the waterways to log sightings of marine mammals. With your help in logging sightings, our researchers can record those sightings, identify species in our watery backyard and assess areas of significance for marine mammals.

    Please note that marine mammals are protected and specific approach distances are in place to ensure our marine mammals (and your own) safety. See MMF Conservation page for specific regulation.

    Fun facts!

    HUMPBACK WHALE FUN FACTS

    • Humpbacks can hunt in groups, simultaneously blowing bubbles into the water to trap prey species. This process is called bubble-netting (Friedlaender et al. 2011). 
    • Male humpback whales sing complex songs to attract females for breeding (Smith et al. 2008), as well as produce unique social vocalisations for other communications (Dunlop & Noad 2007).
    • Female humpbacks and their calves communicate with each other through vocalisations during migration to stay close (Indeck et al. 2020). 
    • One of the only known rare white humpback whales, Migaloo, follows a migration route along the east coast of Australia and occasionally around New Zealand (Beeman 2017)
    • Usually found in pods of up to 12-15 individuals, or in mother-calf pairs (Shirihai & Jarrett 2006).
    • Humpback whale dives usually last for 3-15 minutes, though dives of up to 40 minutes have been recorded, reaching depths of up to 150m (Shirihai & Jarrett 2006). 
    • Mating and calving season is from June to October (Mann et al. 2000). 
    • These whales have a gestation period of 11-12 months and calve every 2-4 years (Mann et al. 2000).

    SOUTHERN RIGHT WHALE FUN FACTS

    • The population of southern right whales in Australian waters are genetically distinct to other populations in the southern hemisphere (Shirihai & Jarrett 2006).
    • Can be found in pods of us to 12 individuals, but usually found in groups of 2-3 (Shirihai & Jarrett 2006). 
    • Dives usually last 10-20 minutes, but there have been recordings of dives lasting up to 50 minutes to a depth of 184m (Shirihai & Jarrett 2006)!
    • Southern right whales have been extensively hunted throughout history, and it was believed in 2014 that populations had recovered less than 15% of their numbers since the cessation of their whaling in 1935 (Fretwell et al. 2014). 
    • Southern right whales can live for more than 70 years (Shirihai & Jarrett 2006)!
    • Mating and calving season is from May to August (Shirihai & Jarrett 2006).
    • These whales have a gestation period of 12-13 months and calve every 2-4 years (Shirihai & Jarrett 2006).

    Marine Mammal Foundation Publication

    Cetacean biodiversity, spatial and temporal trends based on stranding records (1920- 2016), Victoria, Australia
    Chantel Sarah Foord, Karen M. C. Rowe, Kate Robb. PLoS ONE 14(10): e0223712

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