Assessment of the risk of commercial fisheries to New Zealand seabirds, 2006–07 to 2014–15

Seabirds are incidentally captured during commercial fishing operations, but assessing the impact of fishing mortalities on seabird populations is hampered by a lack of information. Seabird bycatch is not fully known, and understanding of seabird populations is limited. To manage the effects of fisheries on seabird populations, risk-based approaches are used to assess the population impacts of commercial fisheries on seabirds. In New Zealand, assessments of the risk to seabird populations from fisheries bycatch have been based on a comparison of the ratio between estimates of incidental captures and estimates of seabird population productivity, following the Spatially Explicit Fisheries Risk Assessment framework. This report presents an update of the previous assessment of the risk of commercial fisheries in New Zealand, for 71 seabird taxa that breed in the New Zealand region.
In this risk assessment, estimates of incidental captures were derived from the captures of seabirds recorded by government observers onboard fishing vessels and from data on fishing effort between 2006–07 and 2014–15, and the risk was calculated using annual average fishing effort for the period from 2012–13 to 2014–15. A Population Sustainability Threshold (PST) was used for seabird population productivity, a generalisation of the Potential Biological Removal (PBR) index, based on the total number of breeding pairs, and including the uncertainty in all demographic parameters explicitly...