Spanner Crab Ranina ranina

East coast biological stock

The East Coast Spanner Crab stock is shared between Queensland and New South Wales, with Queensland accounting for the largest harvest (90 per cent, based on the reported harvest in 2013).

Total catch of Spanner Crabs has decreased significantly since 2000 (Figure 2). The reduction in catch can be attributed to large reductions in fishing effort (for Queensland, 2.7 million pot-lifts in 2000 compared with 880 000 pot-lifts in 2013), caused by changes in fishery economics, social factors, and creation of marine parks in north-east New South Wales, which led to loss of fishing area and removal of endorsements.

The standardised catch rate of Spanner Crabs from annual fishery-independent surveys (from 2000 to 2013 in Queensland, and 2006 to 2013 in New South Wales) has increased since 2000². In 2013, the survey catch rate was above the target reference point. The survey also shows consistent numbers of small crabs (below the minimum legal size), indicating continued recruitment to the fishery². These fishery-independent indictors are positive in relation to Spanner Crab biomass.

In Queensland, the 2013 commercial fishery standardised catch rate was below the target reference point, but similar to the value calculated for 2000 to 2003². Large reductions in catch and effort between 2000 and 2013 have contributed to this result. The nominal catch rate from the New South Wales commercial fishery in the 2011–12 financial year was within historical levels².

The above evidence indicates that the biomass of both the Queensland and New South Wales parts of the stock are unlikely to be recruitment overfished.

Fishing pressure in Queensland is controlled through a total allowable commercial catch (TACC). The TACC is set biennially, using an empirical model based on fishery catch rates (Queensland) and fishery-independent catch rates (Queensland and New South Wales)³. In 2013, the pooled index (the arithmetic mean of the commercial and survey indices) recommended a reduction in the commercial quota to the base level (1631 tonnes).

In New South Wales, fishing mortality is controlled through input controls (limited entry, zoning, gear limits). Given the small number of licences, and the overall take compared with the take in Queensland, it is unlikely that fishing of the New South Wales part of the stock is having a detrimental effect on the entire east coast stock⁴.

Fishing pressure from the recreational sector is negligible. The estimated harvest by recreational fishers in Queensland and New South Wales is less than 1 per cent of reported commercial harvest in both jurisdictions (Table 3)⁵.

The spawning biomass of the east coast stock is protected through minimum size limits, which aim to allow mature individuals to spawn at least once, and temporal (spawning) closures to protect spawning animals. Egg-bearing females are rarely caught and cannot be retained. These regulations apply to both commercial and recreational fishers. Spanner Crabs are caught through entanglement, and there is evidence that limb damage during removal from the fishing gear leads to increased mortality of discarded crabs⁶, which may offset the benefits of the minimum legal size. Current fishing practices in New South Wales and Queensland aim to minimise damage to discarded crabs to limit such post-release mortality^5,6.

The above evidence indicates that the current levels of fishing pressure in both the Queensland and New South Wales parts of the stock are unlikely to cause the stock to become recruitment overfished.

On the basis of the evidence provided above, the entire biological stock is classified as a sustainable stock.