AUSOCEAN UPDATE

The Sustainability of

in Australia

The Demand Compared to some parts of the world Australians don’t consume cephalopods (octopus, squid, and cuttlefish) very much. The majority of consumption consists of squid as calamari which has quickly become a pub favorite but recently the demand for octopus has increased leading to full, functioning fisheries in Tasmania, West Australia and developing ones in Victoria and South Australia. Octopus, squid, and cuttlefish are excellent examples of sustainable seafood options mainly due to their rapid growth, short lifespan (1-2 years) and quick maturity as opposed to fish who have slower maturity and much longer lifespans, not unusually reaching several decades. This means populations can recover from fishing quickly and sustain themselves whereas long lived species take longer to recover from overfishing. The switch to more sustainable options has even been observed in South Australian waters. Many marine scalefish fishers have been switching their fishing efforts from slow growing fish like snapper and King George whiting to southern calamari since 2011 but even more so since the snapper fishery closed in 2019. So far this increase in calamari catch has caused some concern in some regions such as southern Spencer Gulf where estimated abundance (catch per unit effort) has declined since 2013.

The Plan As the demand for cephalopods grows, management plans need to be developed to protect our wild stocks so that they keep being productive. But because cephalopods as a food source are not as popular as other seafood like fish, not as much is known about basic information such as how long they live and how they respond to their environment. These data are species specific and a lot of the data in Australia is lacking. That’s where I come in! Hi! My name is Erica and I’m a PhD student at the University of South Australia. I love learning about cephalopods and am very passionate about sustainable food. Therefore the overall goal of my research is to help gather more information on the life histories of cephalopods in southern Australia that can then be further used for proper management of wild stocks. One part will be ageing the southern keeled octopus, Octopus berrima, which comprises 97% of the catch in the active octopus fishery in South Australia. Another part will be using microchemistry of the hard parts in southern calamari, Sepioteuthis australis, for seafood provenance (tracing back seafood from where they came from). This also has implications to study population structure. I will also be measuring stable isotopes from Australian giant cuttlefish cuttlebones across a 100+ year time scale to determine if we can use concentrations of carbon isotopes in cuttlebones to measure atmospheric carbon. This study has implications for modern cuttlefish ecology studies as well as paleontology. Additionally, if all goes well, I may even try to raise octopus in captivity to study how stable isotopes in different octopus tissues compare to stable isotopes in the ocean and the food that they eat. This last study will also aid knowledge on how to raise holobenthic octopus (hatchlings hatch out as benthic juveniles as opposed to merobenthic in which they have a planktonic larva stage) for aquaculture. It’s all very exciting stuff and will hopefully add to our wealth of cephalopod knowledge to manage and conserve local cephalopod species.

Erica Durante PhD student UniSA

To find out more visit: www.ausocean.org/