Pāua management procedure: review of current state and prospects for wider application

Summary

Management procedures (MPs) are increasingly being used in fisheries management to link resource assessments to a set of rules that formalise the setting of allowable catches. In a New Zealand context, MPs have been considered for New Zealand abalone (pāua, Haliotis iris) fisheries, which are managed across different quota management areas (QMAs). For example, in all QMAs of PAU 5 (southern South Island), stakeholders agreed to a set of voluntary (non-mandatory) MPs since 2016, to manage the fisheries within the current Total Allowable Commercial Catch set by Fisheries New Zealand. The MPs have been used to set shelving levels at annual general meetings based on offset-year catch-per-unit-effort (CPUE), with discussion about trends supplementing model estimates. Corresponding decisions have been based on informal synthesis of stakeholder views and trends from data. For example, in 2018, the control rule suggested that catches be increased from 35% shelving levels due to an increase in CPUE in PAU~5D. The increase was not applied after deliberations, during which divers attributed the increased CPUE to unprecedented dive conditions that could not be standardised appropriately by the CPUE model. The overall process, therefore, retained a level of empiricism despite the introduction of the formal management framework.

Current changes in the fishery in the form of increased landing of live p=aua with limited or no length-frequency data (or labelling of landings as live or whole frozen), together with concurrent changes from paper-based reporting to electronic reporting, present a difficult challenge for the continuation of MPs in their current form. Fishing for the live and whole-frozen market led to changes in selectivity, which likely affect both CPUE and the size of fished pāua.

These changes disrupted initial plans to disregard reported CPUE and use predicted CPUE from the assessment, determined by length-frequency data, to apply the MPs and counter the anticipated disruptions to the CPUE time series from the change to electronic reporting. Given the lack of data on the live-trade pāua, this fishery cannot currently be incorporated in the assessment model. The average size of fished pāua is likely to be underestimated, because only pāua not destined for the live and whole-frozen trade are measured as part of the commercial catch-sampling length-frequency programme. Current changes led to MPs being shelved for decisions regarding the 2020–21 fishing year.

Further work is required to understand changes from electronic reporting, particularly regarding reported effort, to ensure reliable standardisation. In addition, robust data collection systems need to be established to capture data for pāua destined for the live and whole-frozen trade. This data collection is necessary to avoid that this fishery component biases information of the overall pāua catch, and to determine its effects on pāua populations. Combined with this improved data collection, it is also suggested that scales of assessment and management procedures are united with fine-scale management initiatives, such as catch-spreading and local fishing limits. This latter approach will ensure that controls are internally consistent across spatial scales of management.