Hammer Octopus (2020)
Date Published: June 2021
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Hammer Octopus occur along the eastern Australian coast from central QLD 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 QLD and NSW is available. Consequently, stock status is assessed here at the jurisdictional level. Hammer Octopus is classified as undefined in QLD and sustainable in NSW.
Stock Status Overview
The Hammer Octopus has a limited east coast distribution, 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 per cent 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.
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 [QFISH 2020]. Catches of all octopus species have been relatively stable since this peak, averaging about 15 t per year. 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.
|Species||Longevity / Maximum Size||Maturity (50 per cent)|
Lifespan up to 11 months in NSW waters, 49.9 cm maximum total length
No distribution data are provided for Queensland as Hammer Octopus is not separately identified in East Coast Trawl Fishery logbooks.
|Marine park closures|
New South Wales – Recreational (catch totals) Estimate from Murphy et al. , based on a survey of Recreational Fishing Licence households.
New South Wales – Indigenous (Management Methods) 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
New South Wales - Combined octopus species catches that included Hammer Octopus occurred in NSW waters prior to 2010, but are not shown in the chart. Separate species catch data for Hammer Octopus are only available since 2010.
- Boletzky, S v, 1974, The "larvae" of Cephalopoda - a review. Thalassia Jugoslavica 10:45-76.
- Courtney, A, Haddy, J, Campbell, M, Roy, D, Tonks, M, Gaddes, S, Chilcott, K, O'Neill, M, Brown, I, McLennan, M, Jebreen, J, Van der Geest, C, Rose, C, Kistle, S, Turnbull, C, Kyne, P, Bennett, M and Taylor, J 2007, Bycatch weight, composition and preliminary estimates of the impact of bycatch reduction devices in Queensland's trawl fishery, Report to the Fisheries Research and Development Corporation, Project No. 2000/170, Department of Primary Industries and Fisheries, The State of Queensland.
- Doubleday, ZA, Pecl, GT, Semmens, JM and Danyushevsky, L, 2008, Stylet elemental signatures indicate population structure in a holobenthic octopus species, Octopus pallidus. Marine Ecology Progress Series 371:1-10.
- Hall, KC, 2018, Stock status summary 2018 – Octopus (Octopus australis, Macroctopus maorum, O. tetricus and O. pallidus). NSW Department of Primary Industries, Coffs Harbour, NSW, Australia.
- Hall, KC, 2020, Status of Australian Fish Stocks 2020 - NSW Stock status summary – Hammer Octopus (Octopus australis). NSW Department of Primary Industries, Coffs Harbour, NSW, Australia.
- Higgins, KL, Semmens, JM, Doubleday, ZA and Burridge, CP 2013, Comparison of population structuring in sympatric octopus species with and without a pelagic larval stage. Marine Ecology Progress Series 486:203-212.
- Jacobsen, IP, Zeller, B, Dunning, MC, Garland, A, Courtney, AJ and Jebreen, EJ 2018, An ecological risk assessment of the southern Queensland East Coast Otter Trawl Fishery and River and Inshore Beam Trawl Fishery. Project Report. Department of Agriculture and Fisheries, Queensland.
- Murphy, JJ, Ochwada-Doyle, FA, West, LD, Stark, KE and Hughes, JM, 2020, The NSW Recreational Fisheries Monitoring Program - survey of recreational fishing, 2017/18. Fisheries Final Report Series No. 158.
- Nuttall, AM, 2009, Determining the age and growth of Octopus australis (Hoyle, 1885). University of Technology, Sydney, NSW, Australia.
- QFish, Department of Agriculture and Fisheries, www.qfish.gov.au
- Reid, A, 2016, Cephalopods of Australia and Sub-Antarctic Territories. CSIRO Publishing, Clayton South, Victoria.
- Schnierer, S and Egan, H, 2016, Composition of the Aboriginal harvest of fisheries resources in coastal New South Wales, Australia. Reviews in Fish Biology and Fisheries 26:693-709.
- Stranks, T and Norman, M, 1992, Review of the Octopus australis complex from Australia and New Zealand, with description of a new species (Mollusca: Cephalopoda). Memoirs of the Museum of Victoria 53:345-373.
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