MLSSA member and documentary filmmaker Dan Monceaux has just announced via ForceofNature.eco that he’s working with scientists and the South Australian Museum to help complete a 172 year-old taxonomic task. He’s currently reaching out to the recreational fishing community, asking for donations of any cuttlefish caught in Gulf St Vincent. Here’s why.

The Giant Australian Cuttlefish, Sepia apama, is known to occur in temperate and sub-tropical Australian waters- from Brisbane, Queensland in the north-east, south to Tasmania and west to Shark Bay, Western Australia. Unpublished scientific study data indicates that several distinct populations of Giant Australian Cuttlefish occur across its range, and it’s also possible that some of those might even turn out to be different, yet-to-be-described species.

So why has a conspicuous animal that can grow to a maximum weight of more than 10 kilograms taken this long to be recognised as a likely species complex? Well, it doesn’t help that Giant Australian Cuttlefish can change the colour and texture of their skin in an instant, but that’s not the main reason. The problem actually dates back to when the species was first described back in 1849. You see, the British naturalist John Gray who first drew and wrote his description of Sepia apama did so from an incomplete animal… in fact, from a cuttlebone alone. The cuttlebone was collected in the Port Adelaide area, so most likely once belonged to a living member of the cuttlefish population of Gulf St Vincent.

So before other populations can be compared, the work of Gray needs to be revisited, and extended to describe the complete animal. Both male and female specimens are required for this, hence Monceaux’s call to action with a target of 10 specimens including both genders. Several options for collection methods were thought through, but in the end, reaching out to recreational fishers made the most sense. Cuttlefish occasionally appear in the photos of catches made by Gulf St Vincent fishers posted on Facebook, and that’s exactly how the first specimen, pictured in this article, was secured. The collector was keen fisherman Tony Bainbridge, who caught the animal with a lure at 20 metres depth while fishing from a boat out of Seaford. He supplied these photos, then kept the animal frozen until collection.

BUT WHAT ABOUT THE CUTTLEFISH AGGREGATION?

Before anyone squeals about this project being against the interests of protecting the cuttlefish aggregation of neighbouring upper Spencer Gulf, an explanation is due. Scientists have already concluded that there is no overlap between Giant Australian Cuttlefish in Gulf St Vincent with those of Northern Spencer Gulf. Also, the sparse distribution of Giant Australian Cuttlefish in Gulf St Vincent makes them difficult to target. If anything, this project serves to help inform the management of the northern Spencer Gulf population. Once the Gulf St Vincent population’s description is complete, a description can be made for the northern Spencer Gulf population as the two can be properly compared. After that, the northern Spencer Gulf population may be assigned a new name as a species or sub-species of its own. Much of the genetic work is already done, so what really needs comparing are the physical characteristics.

So the collection of around ten individual cuttlefish from along hundreds of kilometres of Gulf St Vincent coast will:

  1. complete the description of Sepia apama, commenced in 1849
  2. enable the comparison of cuttlefish from other populations around Australia and
  3. assist with the management of those populations from both fishing and conservation perspectives in the future.

If you know anyone who’s caught a cuttlefish in Gulf St Vincent before, please let them know about this project. Further details, including what do do when you catch one can be found here. Specimens will be donated to the South Australian Museum and Dan will arrange the collection and depositing.

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