This study provides an assessment of the impact of fishing-related fatalities on the populations of 35
marine mammal (sub)species that inhabit New Zealand waters. The assessment included mortalities
caused by trawl, longline, set-net and purse-seine fisheries within New Zealand’s Exclusive Economic
Zone (EEZ). The risk assessment was an implementation of the Spatially Explicit Fisheries Risk Assessment
(SEFRA) method. Risk was defined as the ratio of Annual Potential Fatalities (APF; an estimate of
the number of marine mammals killed in fisheries each year) to the Population Sustainability Threshold
(PST; a measure of the population productivity). A risk index higher than one indicates that fisheries
mortalities are at a level that may prevent the population increasing to, or remaining above, half the
carrying capacity in the long term.

Commercial fisheries in New Zealand waters interact with non-target species, with some of these interactions resulting in incidental captures and mortality. Captures of protected species are documented by fisheries observers, providing an independent record of the number and identify of the species captured in New Zealand’s Exclusive Economic Zone (EEZ). For species with sufficient numbers of observed captures, the observer records and fishing effort data are used to develop statistical models to estimate the total number of captures across species and fisheries in New Zealand waters. This study presents total capture estimates of marine mammals and sea turtles in trawl and longline fisheries for the period between the 1995–96 and 2014–15 fishing years (a fishing year runs from 1 October to 30 September).

Trawl fisheries have direct impacts on seabed habitats and fauna that are likely to alter ecosystem function over time. We used towed cameras and corers to study changes in benthic community composition across gradients of cumulative trawling pressure in two areas on Chatham Rise. We found that trawling accounted for up to 17 % of variation in benthic epifaunal communities. Our results indicate that trawling modifies the structure and functional composition of epifaunal communities, with reduction in the density of sensitive taxa and overall evenness and diversity.

The seabird risk assessment provides risk rankings for seabirds in commercial fisheries in New Zealand waters. This study used simulated fishing effort and observer data to test the sensitivity of the seabird risk assessment to a reduction in observed captures. The results indicate that, because of low observer coverage, the government will be unable to demonstrate that seabird risk reduction goals have been met, even if no seabird captures are reported by observers for three years.

This report provides the fourth iteration of the plan to provide a list of all fish and invertebrate bycatch species in New Zealand deepwater fisheries, with estimates of annual catch weights, that can be relatively rapidly produced and regularly updated.

Dedicated and opportunistic studies on the effects of fishing on the seabed have been collated across a range of New Zealand habitats, to determine the most useful approaches, and effects at the scale of the fishery. The magnitude of the effects varied with effort gradient, were greater for epifauna, and were greater for dedicated sampling studies. Effects included reduced diversity and number of taxa. Species that stand erect of the seabed or live on the sediment surface were most vulnerable.

We analyse the distribution of bottom contact trawling between 89/90 and 12/13 using TCEPR data. Eleven target species and an aggregate of all tier 1 and 2 species are analysed. Statistics for the footprint and effort per 5 x 5km cell in relation to depth zones, fishable area, habitat and preferred habitat of each species are provided. The footprint for all tier 1 and 2 species is estimated at 347 290km2 (~ 8% of the EEZ & TS), the cumulative area of tows is 175 204km2 (~ 24% of EEZ& TS cells).

This report describes population modelling of the Hooker’s sea lion (Phocarctos hookeri) population and evaluating bycatch control rules for the SQU 6T fishery. The model is integrated, Bayesian and age-structured, and used population data, bycatch estimates and fishing effort. The posterior distribution of parameters, estimated with McMC, was the basis of an operating model used to evaluate alternative bycatch control rules. Additional results from an external review in 2013 are also presented.