Pale octopus ​Octopus pallidus

Tasmania

In Tasmania, where most of the total commercial catch is taken, stock status is based on consideration of commercial catch-and-effort data, which are assessed by determining fishery performance indicators and comparing them with reference points. Commercial catch and catch per unit effort (CPUE) are used as proxies, as there are insufficient data to calculate fishing mortality or biomass. These are compared with the reference periods 2000–01 to 2009–10 for catch, and 2004–05 to 2009–10 for CPUE. Since November 2004, a 50‑pot sampling program has been conducted in the fishery. Under this program, fishers are required to collect all octopuses caught in 50 randomly selected pots from a single line, representing 10 per cent of a standard commercial line.

In the Tasmanian Octopus Fishery, catches have fluctuated around 85 (±7) tonnes (t) since 2005–06 but reached a historical high of 117 t in 2012–13. Effort also fluctuated around 299 900 (±14 250) pot-lifts between 2005–06 and 2011–12, but over the last two fishing seasons has increased to an average of 425 800 pot-lifts. The standardised CPUE, calculated from the 50‑pot random sampling program, suggests a decline in catch rate, particularly over the past three fishing seasons (2011–12 to 2013–14), to around 60 per cent of the 2004–05 reference year. This was after CPUE fluctuated at around 88 per cent over the previous five fishing seasons. The unstandardised CPUE from the 50-pot random sampling program (0.32 octopuses per pot-lift) has been less than the lowest number of octopuses per pot-lift from the historical reference period (0.39 octopuses per potlift between 2004–05 and 2009–10), therefore exceeding the trigger reference point.

Although semelparous species such as Pale Octopus have high interannual variability in catch due to seasonality, and variations in recruitment, food availability, behaviour and individual migration³, the recent decline in CPUE, coupled with an increase in fishing effort, suggests that fishing mortality could be reducing the spawning biomass and affecting recruitment. Brooding female octopuses are the most vulnerable to fishing pressure, as they use pots as shelters to deposit their eggs^4,5. Consequently, the removal of brooding females may adversely affect egg production. Scientific studies have previously found evidence of size-selective fishing in Tasmania, with female weight-at-age decreasing and growth increasing across sampling seasons, potentially impacting egg production and future recruitment to the fishery⁵. The above evidence indicates that the stock is not yet considered to be in a recruitment overfished state, but the current level of fishing pressure is likely to cause the stock to become recruitment overfished.

On the basis of the evidence provided above, Pale Octopus in Tasmania is classified as a transitional–depleting stock.

Victoria

In Victoria, octopus is a byproduct species caught across various fisheries, primarily in the Rock Lobster Fishery. During the past decade, up to 90 fishers have reported landing octopus species, but catches have remained low, averaging 27.4 t over this period. Catch in 2013 was 24.9 t. Pale Octopus is undifferentiated from other octopus species in Victoria, and therefore stock assessment methods cannot be formally employed. Insufficient information is available to confidently classify the status of this stock.

On the basis of the evidence provided above, Pale Octopus in Victoria is classified as an undefined stock.