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The stock structure of Hapuku in Australian waters is unknown. Hapuku stock status at the jurisdictional level is sustainable in WA, negligible in QLD and SA, and undefined in NSW and Commonwealth waters.

The stock structure of Hapuku throughout Australian waters is unknown. Life history characteristics similar to Bass Groper (Polyprion americanus) suggest mixing across broad geographic areas [Ball et al. 2000]. However, Beentjes and Francis [1999] inferred the likelihood of separate stocks within New Zealand based on tagging studies of Hapuku, despite recorded movements of up to about 1 400 km. Paul [2002] reported on the stock structure of Hapuku (and Bass Groper) in New Zealand, concluding that stock structure could not be described, and that there was insufficient data describing the life history characteristics to distinguish different stocks. Wakefield et al. [2010] described differences in aged-based demography and reproduction of Hapuku among regions of Western Australia, and likely pan-oceanic mixing of the broader Hapuku population (including Indian Ocean). No such investigations have been done on Hapuku throughout eastern and south eastern Australian waters to develop our understanding of stock structure. It is likely Hapuku in eastern and south eastern Australian waters constitute one or more stocks of a greater population and fisheries within this region access this stock or subset of stocks in support of their annual catches. Panmixia could be expected throughout the region, owing to the extended larval/juvenile phase (years) and large-scale genetic homogeneity of congener P. americanus which has similar life-history traits [Ball et al. 2000, Roberts 1996, Sedberry et al. 1996, Wakefield et al. 2010]. Evidence in support of a single biological stock, or stock structuring within broader Australian waters is limited.

Here, assessment of stock status is presented at the jurisdictional level—Commonwealth, Western Australia, Queensland, New South Wales and South Australia.

Western Australia

The Hapuku catch in Western Australia is predominantly by commercial line fishers operating along the lower west and south coasts. An age-based assessment from sampling 2005 and 2006 south coast catches estimated fishing mortality (F) to be within target and threshold levels [Wakefield et al. 2010]. More robust modelling of the same data was undertaken in 2018, assuming variable recruitment and age-based selectivity. This updated and unpublished assessment generated two spawning potential ratio estimates (± 95 per cent confidence intervals) using the per recruit and dynamic pool methods: 0.48 (0.43–0.54) and 0.44 (0.38–0.50) respectively, indicating a high likelihood that spawning potential was above the threshold reference level of 0.30. Simultaneously generated estimates of F and natural mortality M per year were 0.045 (0.04–0.05) and 0.09, respectively, giving an F/M estimate of 0.50 (0.42–0.60), well below the threshold reference level of 0.67. The new analysis shows the breeding stock was adequate and fishing mortality sustainable at the time the sample was collected. An updated age-based assessment with recent data is underway. 

On the basis of the evidence provided above, Hapuku in Western Australia is classified as a sustainable stock.

Hapuku biology [Ball et al. 2000, Paxton et al. 1989, Wakefield et al. 2010]

Distribution of reported commercial catch of Hapuku

Western Australia – Recreational (management methods) Recreational Fishing from Boat Licence is required for use of a powered boat to fish or to transport catch or fishing gear to or from a land-based fishing location.

Queensland – Indigenous (management methods) for more information see https://www.daf.qld.gov.au/business-priorities/fisheries/traditional-fishing

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

Commercial catch of Hapuku - note confidential catch not shown

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