Updating New Zealand’s bycatch extrapolation and risk assessment - including 2013-14

This paper summarises the updates to the time series of New Zealand’s estimates of total seabird bycatch and recent modifications of the extrapolations method used. The paper also summarises changes to the quantitative risk assessment and its underlying methods.
Bycatch extrapolations have been continued and now extend to include the 2013/14 fishing year. Up until 2014, New Zealand’s extrapolation of seabird bycatch was increasingly complex with up to 35 different statistical models being used in order to maximise the accuracy of the results. However the increased complexity meant that the resulting modelled uncertainties were not directly comparable.
The most recent set of extrapolations have utilised a simplified extrapolation (strata-based ratio) method that is consistent across all seabird species. This approach is stratified by areas and allows for a random year effect for larger vessels (as these have been observed at a higher rate). These in general compared reasonably well with previous estimates and the quantitative seabird risk assessment.
New Zealand’s quantitative risk assessment which underpins New Zealand’s NPOA- Seabirds was rerun in 2015. Currently some aspects of the methods are being reconsidered; such as whether population trend can be included, and then the risk assessment will be rerun in 2016.
New Zealand is looking to conduct a quantitative seabird risk assessment, including all relevant ACAP species, across the southern hemisphere building on the approach taken for the New Zealand’s commercial fishing. The current proposal is to iteratively repeat and improve the risk assessment as further data becomes available. The first iteration will be based on coarse observer and fishery effort data that is publically available.