Large-scale fishing in the Southern Ocean began in the 1960s. During the first few decades, fishing was largely unregulated. This resulted in several species of fishes, (such as the marbled rock cod (Notothenia rossi)) being driven to such low numbers that they can no longer be commercially fished.
Many countries that fish in the Southern Ocean, including Australia, are now members of treaties such as CCAMLR (the Convention for the Conservation of Antarctic Marine Living Resources). CCAMLR aims to prevent unregulated fishing in the Southern Ocean. Permitted fishing is managed using all available scientific knowledge to minimise the risk of fishing causing further damage to fish stocks and the ecosystem.
The Australian fishery catches toothfish around Macquarie Island. Both toothfish and mackerel icefish are fished around Heard Island and McDonald islands (HIMI). Patagonian toothfish are caught using trawl nets or hooked on longlines, while icefish are caught exclusively using trawl nets.
The Australian Antarctic Division works closely with the Australian Fisheries Management Authority (AFMA) to collect data on fishing activity and catches in waters around Australian Territories in the Southern Ocean. Scientific observers are present on all Australian fishing vessels and collect data including:
- where fish are caught
- how many fish are caught
Observers also tag toothfish and look for any recaptured fish, which provide information on movement and growth of toothfish. Our research shows that several toothfish tagged around the Heard and McDonald islands have been recaptured thousands of kilometres to the northwest, by French vessels fishing around Île Crozet.
Observers collect otoliths (ear bones) from toothfish. At the Australian Antarctic Division we prepare and analyse these ear bones to work out how old each toothfish is and how fast it has grown. Each ear bone grows in a series of layers, which appear as rings in slices cut from each otolith – just like the growth rings in a tree.
All the data collected, is used to better understand the biology and population cycles of fishes, their linkages to other species in the ecosystem, and how many fish can be taken in each season by the fishery.
Fisheries research reports
- An assessment of the vulnerability of benthic habitats to impact by demersal gears (2014) PDF
- The spawning dynamics of patagonian toothfish in the Australian EEZ at HIMI and their importance to spawning activity across the Kerguelen Plateau (2012) PDF
- Robust characterisation of the age structure, growth and recruitment of toothfish in the Macquarie Island and HIMI fisheries (2012) PDF
- Evaluating gear and season specific age-length keys to improve the precision of stock assessments for patagonian toothfish at HIMI (2009) PDF