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The Western Australian Rock Octopus, or Octopus djinda, is endemic to the temperate waters of WA from Shark Bay to Esperance. The species is captured in specialised traps, and the stock is classified as sustainable.

Photo, Anthony Hart, Department of Primary Industries and Regional Development, Western Australia.

OcOctopus djinda (Subfamily Octopodinae), or the Western Rock Octopus, is endemic to the temperate waters of Western Australia from Shark Bay to Esperance. It is closely related to the cosmopolitan Octopus vulgaris species complex, and to Octopus tetricus on the east coast of Australia and New Zealand, but has been conclusively identified as a separate species through genetic and morphometric studies [Amor and Hart, 2021; Amor et al. 2014]. Here, assessment of stock status is presented at the biological stock level for Western Rock Octopus—Western Australia.

Western Australia

Harvest of Western Rock Octopus in Western Australia is managed by a formal harvest strategy, as defined in the Octopus Resource of Western Australia Harvest Strategy 2018–22 [DPIRD 2018]. The main index of abundance is standardised catch per unit effort (CPUE) based on the catch rate of octopus from specialised traps [Hart et al. 2019]. The standardised catch per unit effort (CPUE) in the Western Rock Octopus fishery in 2022 was 0.73 kg/trap, which was 50% above the target of 0.48 kg/trap. Western Rock Octopus was subject to a comprehensive resource assessment which addressed biology, fishing efficiency and stock abundance and distribution [Hart et al. 2018]. The overall conclusion was that the stock is highly productive, with a maximum age of 1.5 years, as well as abundant and widely distributed along the west and south coast of Western Australia. The estimated area of fished habitat in 2022 was 3,572 km² and this was estimated to be around 18% of the habitat area on the West Coast of 20,073 km² [Hart et al. 2019]. The above evidence indicates that the biomass of this stock is unlikely to be depleted and that recruitment is unlikely to be impaired. The above evidence also indicates that the current level of fishing mortality is unlikely to cause the stock to become recruitment impaired.

Based on the evidence provided above, the Western Australian Western Rock Octopus management unit is classified as a sustainable stock.

Octopus djinda (Subfamily Octopodinae), or the Western Rock Octopus, is endemic to the temperate waters of Western Australia from Shark Bay to Esperance. It is closely related to the cosmopolitan Octopus vulgaris species complex, and to Octopus tetricus on the east coast of Australia and New Zealand, but has been conclusively identified as a separate species through genetic and morphometric studies [Amor and Hart, 2021; Amor et al. 2014]. Here, assessment of stock status is presented at the biological stock level for Western Rock Octopus—Western Australia.

Distribution of reported commercial catch of Western Rock Octopus.

Western Australia - Recreational (Catch Volume) [Ryan et al. 2022].

Commercial catch of Western Rock Octopus - note confidential catch not shown.

1. Amor, MD and Hart, AM 2021, Octopus djinda (Cephalopoda: Octopodidae): a new member of the Octopus vulgaris group from southwest Australia. Zootaxa, 5061(1): 145-156
2. Amor, MD, Norman, MD, Cameron, HE and Strugnell, JM 2014, Allopatric speciation within a cryptic species complex of Australasian octopuses. PLoS One, 9: e98982–13.
3. Department of Primary Industries and Regional Development 2018, Octopus resource of Western Australia harvest strategy 2018–2022. Fisheries Management Paper No. 286. Department of Primary Industries and Regional Development, Western Australia, Perth. 31pp.
4. Hart, AM, Murphy, D, Hesp, SA and Leporati, S 2019, Biomass estimates and harvest strategies for the Western Australian Octopus aff. tetricus fishery. ICES Journal of Marine Science, 76(7), 2205-2217.
5. Hart, AM, Murphy, DM, Harry, AV and Fisher, EA 2018, Western Australian Marine Stewardship Council Report Series No. 14: Resource Assessment Report Western Australian Octopus Resource. Department of Primary Industries and Regional Development, Western Australia. 114pp.
6. Leporati, SC and Hart, AM 2015, Stylet weight as a proxy for age in a merobenthic octopus population. Fisheries Research. 161: 235-243
7. Leporati, SC, Hart, AM, Larsen, R, Franken, LE and De Graaf, MD 2015, Octopus life history relative to age, in a multi-geared developmental fishery. Fisheries Research 165: 28-41
8. Ryan, KL, Lai, EKM and Smallwood, CB 2022, Boat-based recreational fishing in Western Australia 2020/21, Fisheries Research Report No. 327 Department of Primary Industries and Regional Development, Western Australia. 221pp.