*

The Hammer Octopus occurs along the east coast of Australia from central Queensland to southern NSW. While stock structure is unknown, the species has biological traits that suggest a single biological stock is unlikely. Additionally, no joint stock assessment covering both Queensland and NSW is available. Consequently, stock status is assessed here at the jurisdictional level. Hammer Octopus is classified as undefined in Queensland and sustainable in NSW. 

The Hammer Octopus is distributed along the east coast of Australia from central Queensland to southern New South Wales [Reid 2016]. The stock structure of Hammer Octopus is currently unknown. However, on the basis of the relatively large size of mature eggs (8–12 mm, equating to 13.7–21.4% of dorsal mantle length), the species is likely to be holobenthic [Boletzky 1974; Stranks and Norman 1992]. Holobenthic octopuses typically have large benthic rather than pelagic hatchlings, with limited dispersal capacity, and show finer scale population structuring across their distributions [e.g., Pale Octopus, Doubleday et al. 2008; Higgins et al. 2013]. Therefore, it is unlikely that Hammer Octopus forms a single biological stock across its geographic distribution. Furthermore, there is no joint stock assessment for this species, so stock status is reported here at the jurisdictional level - Queensland and New South Wales.

Queensland

In Queensland, Hammer Octopus is taken as a permitted by-product species in the East Coast Trawl Fishery. The take of Hammer Octopus is not reported specifically in logbooks, however the species is one of the more common octopus species encountered in the fishery [Courtney et al. 2007]. Commercial harvest of all octopus species reached a peak of 42 t in 1997–98. Catches of all octopus species have been relatively stable since this peak, averaging about 18 t over the last decade to 2021–22. An ecological risk assessment of the East Coast Trawl Fishery identified Hammer Octopus to be at a low to intermediate risk from fishing impacts [Jacobsen et al. 2018]. There is no estimate of recreational harvest of Hammer Octopus in Queensland. 

There are no sustainability concerns for Hammer Octopus given the low catches and low to intermediate ecological risk profile, however there is insufficient evidence to confidently classify the status of this stock. On the basis of the evidence provided above, Hammer Octopus in Queensland is classified as an undefined stock.

[Nuttall 2009]

Distribution of reported commercial catch for Hammer Octopus.

New South Wales – Recreational (Catch). Estimate from Murphy et al. [2022], based on a survey of Recreational Fishing Licence households. Note, estimates for octopus are highly uncertain, with a relative standard error of greater than 30% and based on survey data from fewer than 20 households.

New South Wales – Indigenous (Management Methods). Information is available at: https://www.dpi.nsw.gov.au/fishing/aboriginal-fishing)

Queensland – Indigenous (Management Methods). For more information see: https://www.daf.qld.gov.au/business-priorities/fisheries/traditional-fishing

Queensland – Recreational Fishing (Catch). Data with high uncertainty (Residual Error >50 %) has been excluded and listed as unknown. More information available at: https://www.daf.qld.gov.au/business-priorities/fisheries/monitoring-research/monitoring-reporting/statewide-recreational-fishing-surveys  

Queensland – Commercial (Catch). Queensland commercial and charter data has been sourced from the commercial fisheries logbook program. Further information available through the Queensland Fisheries Summary Report https://www.daf.qld.gov.au/business-priorities/fisheries/monitoring-research/data/queensland-fisheries-summary-report 

Queensland – Commercial (Management Methods). Harvest strategies available at: https://www.daf.qld.gov.au/business-priorities/fisheries/sustainable/harvest-strategy

Commercial catch data for Hammer Octopus, provided in financial years and aligned according to end year.

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