The trawl footprint describes how much seabed area has been contacted by trawling gear in New Zealand’s territorial sea (TS) and exclusive economic zone (EEZ), but it does not provide a measure of the effect of fishing on seabed communities.

This project used the trawl footprint information, in addition to other sources of information on impacts of contact by trawl gear on seabed fauna, to quantify the potential impacts to seabed communities and habitats.

Fishing gear types were first described and categorised, and footprints for each category of gear were produced. Two published impact assessment methods were applied to the TS and EEZ. The methods had different strengths and weaknesses and the outputs of the two methods were found to be complementary to one another.

The first method applied, the MRSP approach, combines information on gear categories, expert opinion on the vulnerability of seabed fauna to trawl gear, and the bottom contact footprint of trawl fishing. This approach does not consider how the fauna recover over time.

The second method, the relative benthic status (RBS) approach, uses information on the proportion of the seabed area swept by trawls and published information for depletion and recovery rates for seabed fauna considered to be particularly vulnerable to trawling. This method predicts a future state for the seabed fauna assuming no change to fishing effort.

This project provides outputs for both methods that can be used in conjunction with distribution data for seabed fauna to assess impacts of trawling and inform spatial planning processes.

Recognising the shortcomings of the MRSP and RBS approaches, two further approaches were explored and developed using data from the Chatham Rise. One approach aimed to enhance the RBS method by making this more relevant to local seabed fauna by using bycatch data from the Chatham Rise instead of relying on information from international sources. The results were encouraging but indicated that further method development is required.

The second approach expanded a previously applied spatio-temporal modelling approach to assess impacts to fauna thought to be useful indicators of potential trawling effects. It was found that this approach, as with the others, was limited by the available data, and further development is required to improve the utility of this approach in the future.

The Marine Ecology Research Group used detailed field surveys to assess the recovery of the inshore coastal ecosystem affected by the cataclysmic 2016 Kaikōura earthquake.

The earthquake caused seismic uplift from 0.5 to 6.4 m along 130 km of coastline and resulted in widespread die-offs of important flora and fauna and permanent losses to critical habitats.

There was much concern for the fate of diverse intertidal and subtidal communities, which include culturally and commercially important fisheries, such as pāua, and other habitat-forming species like bull kelp.

Shore-based and dive surveys tracked the abundance of over 120 marine species at 16 sites for more than six years. Findings depict major physical and ecological changes over time across sites.

The complex dynamics of recovery are described in detail in this report and clearly show that the effects from this disturbance to the Kaikōura coastal ecosystem are both significant and ongoing.

This long-term study is the first of its kind and provides a detailed data set and quantitative baselines that will help inform future coastal management decisions.

Increasingly frequent and intense extreme weather events such as Cyclone Gabrielle are likely to impact seafloor marine ecosystems by accelerating soil erosion and sediment transport to the ocean by rivers.

The objective of this project was to understand sediment impacts from the February 2023 Cyclone Gabrielle event on marine environments of the Hawke’s Bay and Gisborne regions to enable rapid fisheries management decisions.

We conducted two vessel surveys in June and October 2023 focusing on offshore seabed environments deeper than 15 metres. As part of these surveys we mapped selected areas of the seafloor, surveyed life on the seabed using a towed underwater camera, and obtained sediment core samples.

An ocean current and sediment transport model was designed and implemented to investigate the transport and deposition of sediments after Cyclone Gabrielle. Concentrations of suspended sediments and other parameters in the surface ocean along the east coast of the North Island were estimated from satellite images. This satellite information was used to inform the sediment transport model and to characterise the spatial extent and longevity of the offshore sediment plumes generated by Cyclone Gabrielle. A Seafloor model was used to explore impacts and recovery of seafloor ecosystems following the cyclone.

The analysis of satellite images suggest that the influence of Cyclone Gabrielle lasted approximately two to three months across the Hawke’s Bay and Gisborne coastal marine areas, with surface ocean parameters largely returning to normal by May. The concentrations of suspended sediment at the ocean surface in February were significantly elevated, but they did not exceed values typical of winter months.
Seabed mapping revealed areas of significant sediment erosion, and deposition up to about one metre in thickness, at Pania Reef, Tangoio Reef and Clive outfall area in Hawke Bay. Elsewhere, sediment core observations suggested the presence of fresh muddy deposits of up to about 15 centimetres. Swell waves were resuspending muddy sediments at shallow locations for several months after the cyclone, as was evident by the low underwater visibility during camera deployments.

The abundance and diversity of the sediment fauna sampled in Hawke’s Bay and Gisborne before (2010) and after Cyclone Gabrielle (June and October 2023) tended to increase away from the shore and into deeper waters. Sediment fauna were less abundant in June 2023 when compared with 2010, but appeared to be recovering by October 2023.

Seafloor animal and plant communities are highly likely to have been impacted by sediments at 11 of the 36 locations we surveyed using the towed underwater camera, as assessed by observations including (1) fresh mud layer on the seafloor, (2) animal/plant life in poor condition, and/or (3) absence of seaweed at shallow depths. However, for most of these locations a direct link to Cyclone Gabrielle cannot be demonstrated because no information on the distribution of seafloor organisms is available from before the cyclone. The likely exception is Wairoa Hard in Hawke Bay, where available information shows that kelp and sponges were present before the cyclone but were almost completely or completely absent after the cyclone. Whether this loss of habitat has led to reductions in associated fish populations is unclear.

Although limited by the availability of data, the ocean current and sediment transport model produced realistic predictions of suspended sediment concentrations and deposition at the seafloor. In the days following the cyclone, sedimentation in Hawke Bay was predicted to occur mainly close to shore in the western and central parts of the bay. In the Gisborne region, there was deposition of up to about 10 centimetres of sediments offshore of Poverty Bay and along a narrow band of the coast to the north near Tokomaru and Tolaga bays. These model predictions are broadly consistent with observations from the sediment core samples.

The Seafloor model showed small declines in structure-forming organisms such as sponges for Hawke’s Bay following Cyclone Gabrielle. These declines were not substantial, most likely because the region is already impacted by decades of fishing and increased sedimentation. The Seafloor model predicted weaker cyclone impacts for Gisborne than Hawke’s Bay and indicated that continued trawling may slow down recovery of seafloor communities following extreme weather events.

The lack of pre-cyclone information was a major obstacle in assessing the potential impacts of the cyclone on seabed ecosystems. Information collected as part of this project now form a valuable baseline that will inform future impact assessments in the region. Another limitation is the inability to use towed cameras to survey inshore habitats for extended periods because of poor underwater visibility. A precautionary approach could be warranted in the period following an extreme weather event until key habitats and ecosystems can be surveyed, and fish stocks and catch levels should be carefully monitored in the years following the event.

Sediment transport modelling is a promising tool for rapidly identifying areas most at risk from sedimentation following extreme weather events. However targeted sampling of sediment and water parameters under normal and flood conditions would help improve the accuracy and reliability of model predictions. The Seafloor model could be used to explore how spatial changes in fishing effort could enhance recovery following extreme weather events and could be improved through better information on the distribution of seafloor sediment and reefs and their associated animal and plant communities, particularly in the Gisborne region.

The impact of extreme weather events is made worse by decades of increased sedimentation in New Zealand’s marine environments. Addressing the long-term issue of sedimentation in marine ecosystems and the impacts of extreme weather events will require addressing the factors that have made New Zealand’s catchments more prone to erosion.

The Spatially Explicit Fisheries Risk Assessment framework has recently been updated and applied to assess the fisheries risk to seabird populations within the New Zealand EEZ. In the current report, the approach is applied to seabirds globally in the southern hemisphere. Catchabilities were estimated from New Zealand captures. Then global fishing effort and species distributions were collated and used to assess the risk to seabirds from predicted fisheries captures throughout their range.

A novel spatial risk assessment framework is proposed, based on the Spatially Explicit Fisheries Risk Assessment (SEFRA) and the Sustainability Assessment for Fishing Effects (SAFE). Risk is the probability that exploitation exceeds the Impact Sustainability Threshold (IST). Exploitation is estimated from the catchability and effort, using prior information on either the catchability or the population size. It is applied to shark and turtle species with different data characteristics.

This report details an implementation of the Spatially Explicit Fisheries Risk Assessment (SEFRA) framework to seabirds in the New Zealand Exclusive Economic Zone, attempting to quantify the impact of New Zealand commercial fisheries on New Zealand populations of seventy-one seabird species. As part of the project both the biological and fishery input data have been updated, as well as the structure of the model itself.

This report provides a comprehensive overview of fishery data inputs for assessment of the risk of New Zealand commercial fisheries to New Zealand seabird populations. The risk assessment uses the Spatially Explicit Fisheries Risk Assessment (SEFRA) framework, which requires spatially resolved fishing effort and capture data. These data inputs were extracted from the Protected Species Capture database (version 6; up to and including the 2019/20 fishing year) and prepared for analysis.

This report provides a comprehensive overview of biological inputs for assessment of the risk of New Zealand commercial fisheries to New Zealand seabird populations and was generated as part of Fisheries New Zealand project PRO2019-10. The biological inputs were reviewed and updated where necessary, focusing on high-risk or highly abundant species, and restructured for the updated model formulation. The risk assessment model is described in an accompanying AEBR.

As part of the development of spatially explicit fisheries risk assessment methodologies for chondrichthyans, spatial distribution modelling methodologies were tested on carpet shark, school shark, great white shark, and green turtle as well as on one simulated dataset. Eight recommendations were made for future distribution models including the need to model a year x space interaction as well as both the probability of presence and catch rate, and the usefulness of simulations.

The spatially explicit fisheries risk assessment (SEFRA) of Hector’s and Māui dolphins was updated and outputs were reported for Hector’s dolphins in three local-scale areas: the north coast of the South Island, the Kaikōura coast, and the south coast of the South Island. This analysis included a substantial revision of the model used to estimate the spatial distribution of the dolphins, as well as an update of the fisheries data required by the SEFRA model.

The study summarised diets of top predators in New Zealand waters and estimated the spatial-temporal distribution of many of their prey species caught in inshore fisheries. These were consistent with previous estimates and with existing information and could be used as inputs in other processes such as spatial risk assessment models. Care should be taken for species such as squid or hoki where only the shallow part of their range was included and species groups such as jack mackerel or rattail.

This project estimated the at-sea distribution within the New Zealand EEZ of 11 seabird taxa considered to be most at risk from captures by New Zealand commercial fishing. Predictive habitat models fitted to spatial information were used to predict at-sea distribution of each taxon for each month. Seabird tracking data were used to derive monthly proportions of birds within the EEZ, which were nearly always lower than those assumed by the most recent multispecies seabird spatial risk assessment.

Variables that could potentially influence non-protected species bycatch in surface longlining were assessed. For example, seabird captures were influenced by variables such as moon phase and start month, as well as fishing behaviour-related variables, such as whether the tori line was over the bait entry point. A main conclusion from a post-hoc workshop was that a set of mandatory variables is required to reduce data scarcity limiting the assessment of mitigation measures.

This report gives a protocol for Type 1 monitoring of Marlborough Sounds salmon farms and fits within broader best management practice guidelines for assessing benthic enrichment. It provides a standardised approach for science providers who undertake rapid benthic health assessments around these farms. Type 1 monitoring is the least intense form of monitoring with greater emphasis on qualitative indicator variables that can be rapidly evaluated enabling quick feedback on benthic health.

This work reassesses the potential impact of historical setnet fishing on Māui dolphin, replicating previous analyses in combination with updated catch rate estimates. Catch rates for Hector’s dolphin around Banks Peninsula have been applied to Māui dolphin, and aerial surveys conducted in 2012/13 resulted in Hector’s dolphin abundance estimates that were greater than those from boat-based surveys conducted in 1998–2000. As such, catch rates may be much lower than estimated previously.

An updated risk assessment was conducted for 54 New Zealand marine mammals using a multi-species spatially explicit risk assessment. Goodness-of-fit assessments indicated reasonable performance to predict total number of captures for pinniped and delphinid species with >5 captures, but poor performance to predict the spatial location of those captures. Poor performance may be due to inappropriate structural model assumptions or to biological inputs. Results should be interpreted with caution.