Divers fear Australia's giant cuttlefish could be in danger, as anecdotal reports suggest their numbers are declining and surviving animals are displaying strange behaviour.
Internationally, the species is listed as near threatened with extinction by the IUCN, but in NSW these docile giants of the sea can legally be speared for recreational pleasure or hauled in as bycatch. Official data in this state about their numbers is hard to find.
Giant cuttlefish don't live beyond two years, but during their short lives the creatures are highly expressive and curious of humans. Sydney snorkeler Ian Donato frequents Cabbage Tree Bay in Manly, and is determined to protect future generations of the species.
He is one of thousands who have signed a Change.org petition urging the state government to better protect them.
“There’s nothing quite like being in the water with them, they’re approachable, and they can just be there perfectly levitating above you,” Ian told Yahoo News Australia.
“They’re shapeshifters and they are expressive with their skin. Through their skin cells, they’re able to put on all sorts of displays that have to be seen to be believed.”
No sooner do you know them as individuals, you realise their time is about to end. That's part of the compelling nature of them - they're ephemeral.Ian Donato
Government believes giant cuttlefish not a priority
While divers are concerned about what they're witnessing underwater, the state government's fishing regulator, the Department of Primary Industries (DPI) is yet to declare it priority species in need of special protection.
Referring to it by its Latin name, Sepia apama, DPI told Yahoo it's unaware of any declines and said the species is not listed as threatened or endangered in NSW. "The ‘near threatened’ IUCN status is a global rating and does not indicate that a species is at risk of extinction," a spokesperson said.
The Commonwealth rejected listing the species in 2021, but it is included on international IUCN Red List because the species has declined markedly in South Australia's Spencer Gulf. Because of concerns about its numbers there, it's now protected in the Upper Spencer Gulf by the state government.
Back in NSW, DPI confirmed it hasn't recently undertaken any population assessments of the species.
"NSW DPI has no scientific evidence that Sepia apama populations are declining in NSW. Catch data is not always a proxy for population numbers," it said. "As Sepia apama is not a priority species, regular stock assessments are not conducted."
Fast facts about giant cuttlefish
Males can grow up to one metre long.
They have more colour resolution than your mobile phone.
Like the octopus, cuttlefish belong to the cephalopod family.
What weird behaviour are the giant cuttlefish displaying?
The woman behind the Change.org petition is diver Dr Kate Ahmad who is particularly concerned about the impact recreational fishing is having on Sydney's beloved giant cuttlefish. It’s attracted almost 10,000 signatures since it was launched a week ago, calling specifically for a ban on spearing them between Palm Beach and Wollongong.
Kate compares the gentle creature’s predicament to that of the much-loved blue gropers which are now protected — spearing them can result in an $11,000 fine.
Outside of the Manly marine reserve where Kate dives, there have been reports of numerous giant cuttlefish speared. “Given the paucity of data generally about cuttlefish numbers in NSW, we started to become concerned numbers are dropping,” she said.
During twice-weekly dives, she’s been concerned the giant cuttlefish are strangely hiding in their caves. Dozens of other divers around NSW have also noticed, and they’ve been sharing their worries across online forums.
“We usually start to see them come out of their dens in around May for their breeding season, but this year they just didn’t really show up,” she told Yahoo News Australia. “The few that have been seen during this time haven’t been seen mating.”
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