Marine Stewardship Council Risk-Based Score

A qualitative risk analysis was conducted for each species, following protocols by the Marine Stewardship Council (MSC) based on an approach established by the CSIRO (Hobday et al. 2011). The Risk-Based Framework (RBF) described within the MSC Standard is suitable for assessing fisheries with limited data and for which primary indicators may be unavailable or problematic.  The RBF process is described in detail here. The RBF is used to assess the risk of recruitment impairment and stock damage for each of the three octopus species, with the susceptibility component of the Productivity Susceptibility Analysis based on the fisheries that retained the highest catch of each species in 2020/21: the Tasmanian Octopus Fishery (TOF) for Pale Octopus, the Rock Lobster Fishery for Māori Octopus, and the TOF for Gloomy Octopus.

Pale Octopus – Risk-based Framework

<60: Fail – High Risk

The Pale Octopus Fishery within the Tasmanian Octopus Fishery (TOF) scored < 60 in the Marine Stewardship Council – Risk Based Framework (MSC-RBF) analysis, failing assessment with high risk of stock damage. The Productivity Susceptibility Analysis score was based on the assumption that Pale Octopus is a moderately productive secondary consumer, with a short generation time (< 1 year), and a relatively energy-intense reproductive strategy whereby females actively brood egg clutches. Pale Octopus is highly susceptible to capture and the stock susceptible to damage by the fishery. Fishing effort overlaps with > 30% of the stock distribution in Tasmania, suggesting that the stock is readily available to the fishery. The major risk factor identified by the analysis was the high probability of individual octopus encountering and being captured by fishing gear, given that octopus actively seek out fishing gear (pots) as refugia. This risk is exacerbated by the behaviour of female octopus, which use pots as sheltered habitats to lay and brood eggs, and the fact that fishing effort is concentrated in peak brooding season (autumn).

In consequence, commercial fishery CPUE and other catch data (e.g., sex ratio) are unreliable metrics of stock status over time, as octopus might be effectively caught largely regardless of population density. That is, population depletion might occur even if only minor or no declines in CPUE are evident. Furthermore, the attraction of brooding females to fishing gear indicates a high likelihood of damage to recruitment. The Consequence Analysis indicated full exploitation of the stock, with population size representing the most vulnerable subcomponent. Although there is no clear evidence of damage to recruitment, the frequent capture of brooding females suggests that without suitable management there is a high risk of stock damage and recruitment impairment by this fishery.

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Māori Octopus – Risk-based Framework

60 – 80: Pass – Medium Risk

The Māori Octopus fishery within the Tasmania Rock Lobster Fishery scored 60 – 80 in the Marine Stewardship Council – Risk Based Framework (MSC-RBF) analysis, passing assessment with medium risk to stock damage. The Productivity Susceptibility Analysis scores were based on the assumption that this species is a moderately productive secondary consumer with short generation time (< 3 years) and a relatively energy intense reproductive strategy whereby females actively brood large clutches of eggs. Māori Octopus are highly susceptible to capture as catches overlap with >30% of stock distribution in Tasmanian waters, and there is a high risk of juveniles being retained by fishing gear. The Consequence Analysi showed no evidence of impact to any subcomponent, meaning recruitment impairment is unlikely.

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Gloomy Octopus – Risk-based Framework

60 – 80: Pass – Medium Risk

The Gloomy Octopus fishery within the Tasmanian Octopus Fishery (TOF) scored 60 – 80 in the Marine Stewardship Council – Risk Based Framework (MSC-RBF) analysis, passing assessment with medium risk to stock damage. The Productivity Susceptibility Analysis scores were based on the assumption that this species is a moderately productive secondary consumer with short generation time (<1 year) and a relatively energy intense reproductive strategy whereby females actively brood large clutches of eggs. Gloomy Octopus are highly susceptible to capture as catches overlap with >30% of stock distribution in Tasmanian waters, and there is a high risk of juveniles being retained by fishing gear. The Consequence Analysis showed no evidence of impact to any subcomponent, meaning recruitment impairment is unlikely.