Last week a boat strike killed a southern right whale – maybe two – in Moreton Bay. One mangled carcass of a young female finally drifted ashore on Peel Island, where rangers from Parks and Wildlife dragged it above the tide line ‘as high as possible…to allow its natural decomposition to continue.’ Another whale was seen still alive, but with propeller injuries along the length of its body. The calf travelling with the pair has not been seen since Friday, but will surely die as well.
The death of this whale is particularly sad because although the number of humpback whales is rising, and they are now a common sight – even in Sydney Harbour – the southern right whale (Eubalaena australis) continues to struggle and the species remains on the endangered list.
The reason for this lies in the evidence of that floating carcass. Unlike other whales, a dead right whale floats when dead because of its thick blubber, so to whalers, they were the right whales to catch. Not only did they yield more oil, but after harpooning, they could be tethered alongside a vessel, and processed at the whalers’ convenience. So right whales were hunted more than any other baleen whale, and their numbers dropped accordingly.
Whaling off the coast of Australia began virtually from the arrival of the first British colonists. Ships would dump their ‘cargo’ of convicts in Sydney, then head off into the Southern Ocean to hunt for whales. Sperm whales were the most valuable, because of their spermaceti oil, but like all toothed whales they were dangerous too.
Slow moving baleen whales like the humpback and right whale were much easier prey. Humpbacks breed in tropical water off the Queensland coast, but right whales seem to prefer cooler waters. In Australia, that means in calm inlets in South Australia and along the Victorian coast.
So what were these right whales doing in the warmer waters of Moreton Bay?
There are no 19th century records of right whales migrating this far north. Lack of evidence, of course, doesn’t constitute evidence of a lack of whales, but given the colonists’ enthusiasm for harvesting any marine creatures they could profitably kill, including dugong, turtle and other whales, I think someone would have mentioned it. But in the last decade or so, small family groups of right whales have begun to appear off Stradbroke Island and now – disastrously – in Moreton Bay itself.
Mike Noad, an expert on whales at the University of Queensland, has a theory that they are following an old migration route, one that pre-dates the European settlement of southeast Queensland. Early colonial whalers targeted right whales so devastatingly that the southern right whale population had already collapsed by the time the Moreton Bay settlement was founded in 1824. There were no right whales left to follow this minor breeding route northwards.
It seems plausible, though there’s probably no way we will ever know for sure. At present the whales are heading south to the Antarctic, where they will feed on krill during the southern summer. They are slow moving because they can only swim at the speed of their young calves, which were born in the last month or so. For that reason, they need to rest regularly in sheltered bays like Moreton Bay.
But Moreton Bay is no longer a reliable shelter. The bay is a busy place these days. Ferries crisscross the waters, and hydrofoils and water taxis can’t stop quickly. Perhaps they should just slow down.
Boat strikes happen too often, to turtles and dugong as well as whales. What also worries me – as a historian of whaling – is the significance of that name. How many humpbacks and other whale species have been killed by boat strikes in Moreton Bay, but because they were not ‘the right’ whales, their bodies sank to the seabed unrecorded.
See Andrew Darby, ‘Slow down, whales crossing’, Sydney Morning Herald, 2 July 2014.