S. Australian Marine Site Sees 1,000s (Sometimes100X More) Of Giant Cuttlefish Most Years; In 2026, "A Few Dozen"

[hatrack]

Mid-June is usually the peak time for giant Australian cuttlefish to gather near Whyalla, in South Australia’s Spencer Gulf. Nearly every year, they come in their thousands – and sometimes hundreds of thousands – to assemble in the shallows to breed. It’s a globally unique natural phenomenon, celebrated locally as “Cuttlefest”. But so far this year, only a few dozen have turned up.

Associate professor Zoe Doubleday, a marine ecologist at Adelaide University, says it’s “something we haven’t seen before”. While it is difficult to know for certain the cause of such a meagre turnout, on “the balance of probabilities it is likely to do with the [algal] bloom”, Doubleday says. This could be due to direct exposure, or exacerbated by a decline in their food source.

Australia’s 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 is the largest and most destructive algal bloom in the nation’s history. “We know the effect of Karenia on cephalopods is swift and fatal,” says Doubleday, who is researching the impact of the bloom on the group, which includes cuttlefish, squids, octopuses and nautiluses.

EDIT

Giant Australian cuttlefish are the largest in the world. The breeding event in South Australia is so exceptional that the stretch of coastline 15km north-east of Whyalla was added to the National Heritage List in 2023. Formal surveys would be conducted in coming weeks. However, a spokesperson for the state’s department of primary industries says government researchers are “anecdotally receiving reports that population numbers of giant Australian cuttlefish in northern Spencer Gulf seem relatively low”.

EDIT

https://www.theguardian.com/environment/2026/jun/22/south-australia-sa-algal-bloom-whyalla-cuttlefish

[efhmc]

1. Are humans determined to destroy our planet?