Mid-June is usually the peak time for giant Australian cuttlefish to gather near Whyalla, in South Australia\u2019s Spencer gulf.<\/p>\n
Nearly every year, they come in their thousands \u2013 and sometimes hundreds of thousands \u2013 to assemble in the shallows to breed. It\u2019s a globally unique natural phenomenon, celebrated locally as \u201cCuttlefest\u201d.<\/p>\n
But so far this year, only a few dozen have turned up.<\/p>\n
Associate professor Zoe Doubleday, a marine ecologist at Adelaide University, says it\u2019s \u201csomething we haven\u2019t seen before\u201d.<\/p>\n
While it is difficult to know for certain the cause of such a meagre turnout, on \u201cthe balance of probabilities it is likely to do with the [algal] bloom\u201d, Doubleday says. This could be due to direct exposure, or exacerbated by a decline in their food source.<\/p>\n
Australia\u2019s first bloom of toxic Karenia cristata algae, which began in March last year, is still present along the South Australian coastline, including parts of the Spencer gulf. It\u2019s the largest and most destructive algal bloom<\/a> in the nation\u2019s history.<\/p>\n \u201cWe know the effect of Karenia on cephalopods is swift and fatal,\u201d says Doubleday, who is researching the impact of the bloom on the group, which includes cuttlefishes, squids, octopuses and nautiluses.<\/p>\n Sign up for the Breaking News Australia email<\/a><\/p>\n The latest testing results show elevated levels of Karenia algae at eight out of 32 testing sites on the southern Eyre peninsula and in southern Spencer Gulf, with the highest concentrations of 432,899 cells-per-litre at Proper Bay. The government considers levels above 10,000 per litre<\/a> as \u201celevated\u201d, with higher counts suggesting a bloom could be under way.<\/p>\n When Guardian Australia spoke to Manny Katz, from the Whyalla Dive Shop, a few weeks ago, he was feeling nervous but hopeful<\/a>.<\/p>\n Normally by this point in the season, with water temperatures dipping below 17C, there ought to be thousands of cephalopods spread out along the entire Cuttlefish Coast<\/a>, he says.<\/p>\n Cuttlefish numbers have varied year-to-year since surveys began in 1998, from a low of 13,500 in 2013 to 247,000 in 2020. Photograph: Manny Katz<\/p>\n Instead, divers<\/a> have observed a \u201ccouple of dozen hanging around, at a couple of different spots \u2013 that\u2019s pretty much it\u201d. The animals that had turned up were \u201cextremely skittish\u201d and hiding underneath rocks.<\/p>\n \u201cWe\u2019re at this point where, the longer time goes by, the more we\u2019re worried about it,\u201d he says. \u201cThe cuttlefish should be here by now.\u201d<\/p>\n It\u2019s also a big impost on tourism for the town. The Whyalla Dive Shop, which runs dive tours and rents gear, has been keeping people informed in advance of the situation. The business turned away $50,000 worth of bookings for the June long weekend, when the cuttlefish failed to show. But the greater fear is the risk of losing the aggregation, Katz says.<\/p>\n \u201cThis is a world-renowned dive site. A natural phenomenon that we get to experience. And to not have that is really sad,\u201d Katz says. \u201cFrom an environmental point of view, this is catastrophic.\u201d<\/p>\n Special guests a no-show<\/p>\n Cuttlefish numbers have varied year-to-year since surveys began in 1998, from a low of 13,500 in 2013 to 247,000 in 2020.<\/p>\n