This paper focuses on the possible threat that four key pests pose to New Zealand's plantation forestry resource under climate change.

This study provides expert opinion and case study examples of the likely responses of biological control agents and systems to key climate change threats with a focus on the impact on the productive part of the land-based sectors.

To establish end-user requirements for information and advice on how climate change is likely to affect drought and agricultural production in New Zealand and to establish methodologies and timelines required to develop appropriate updated analyses based on the latest climate change scenarios.

This report quantifies the annual carbon emissions associated with current rates of annual disturbance in New Zealand’s pre-1990 and post-1989 forests, within the context of the Durban Agreement. The Durban Agreement includes definitions and a suggested approach to deriving the baseline level of natural disturbance, but the relevant best practice guidance is yet to be finalised. This adds a significant element of methodological uncertainty.

The purpose of the project was to, in collaboration with Aohanga Incorporation, develop a science-based climate change resilience strategy for Aohanga‘s multiple owned Owahanga Farm Station and to develop a social process framework for engaging rural communities and land-owning Iwi Incorporations in climate change mitigation and adaptation.

Plant diseases, a major constraint on New Zealand's horticultural production, are likely to be affected by temperature and rainfall changes resulting from global climate warming. This study undertook a quantitative analysis for key diseases affecting major horticultural crop sectors using disease risk models in use within those sectors, to ascertain likely changes in regional disease and allow the horticultural industry to plan for the future.

Scion, Landcare Research and the University of Canterbury reviewed national and international best practice in steepland plantation forests to understand and minimise the damage from post-harvest landslide and debris flows.

Note, while this document is marked 'confidential', it has since been approved for public release.

Carbon sequestration in plantation forests can be used to offset greenhouse gas emissions to meet New Zealand's international climate change obligations in the Kyoto Protocol. Although Pinus radiata grows quickly, species with higher wood density, such as Eucalyptus fastigata, are likely to be more suitable for plantations aimed at carbon sequestration. The aim of this study was to provide robust tools and models for predicting carbon sequestration for Eucalyptus fastigata.

Note, while this document is marked 'confidential', it has since been approved for public release.

This research projects the potential distribution of four high-impact invasive species under three contrasting climate change models with medium and high emission scenarios. The pest species currently in New Zealand are Buddleja davidii Franchet and Dothistroma needle blight. The potential threats are pitch canker (Fusarium circinatum), and the insect Thaumetopoea pityocampa (pine processionary moth).

This project aimed to evaluate potential agricultural land uses that could provide an alternative to livestock production. In all scenarios, changing the land use to the selected crops increased the profitability. Converting nearly 200,000 ha of pastoral land to crops and mānuka plantations will have a relatively small effect on CH4 emissions. Adoption and development of mitigation technologies is more likely to have a large effect towards meeting future CH4 emission reduction targets.

This report summarises bycatch and discards of fish and invertebrates in New Zealand arrow squid and scampi trawl fisheries for 2002–03 to 2015–16, based on analysis of fisheries observer and commercial catch effort data. Barracouta, silver warehou, and spiny dogfish were the main bycatch species in the arrow squid fishery, with total annual bycatch of 9000–40000 t and discards of 1000–16000 t. Javelinfish, other rattails, and sea perch were the main bycatch species in the scampi fishery, with total annual bycatch of 2400–5600 t and discards of 900–4100 t.

This study estimated the post-release survival of inshore finfish with current commercial minimum legal sizes—blue cod, blue moki, butterfish, kingfish, red moki, red cod, sand flounder, snapper, tarakihi, trevally, and yellowbelly flounder—and those currently allowed to be returned under disposal code X— kingfish, rig, sand flounder, school shark, rough skate, smooth skate, and spiny dogfish.

A questionnaire was developed and circulated to fishers, fishery observers, and scientists with knowledge of each species to obtain their estimates of at-release survival (i.e., the probability the fish/shark was alive when put back into water) and post-release survival (the probability an individual was both alive at release and survived following release). Estimates were obtained for each gear type as well as fishing categories within each gear type, e.g., duration, depth, and bag size. For some species, estimates of post- release survival were informed by literature on the survival of same or similar species.

These data were used with fishery characterisations to model the survival for each species. For species with a minimum legal size, both at-release and post-release survival estimates were used, whereas for those species released under disposal code X, which may only be released if alive and likely to survive, only the post-release survival estimates were used.

The post-release survival from longlines for snapper, kingfish, and rough skate (assuming they are released alive) was “medium-high”, i.e., the lower bootstrapped 90% confidence range was lower than 0.50, but greater than 0.25, and upper 90% confidence range exceeded 0.75. The same survival range was estimated for snapper caught in pots. For snapper, this result was based on expert knowledge and incorporated literature-based mean values based on empirical studies for this species in New Zealand.

However, for rough skate, the result was based on the informed opinion of 2 science experts only (at-vessel survival was assumed to be 100%) and without the benefit of literature-based empirical estimates as none exist for this species. If at-release survival estimates are included for kingfish, the range decreases to “medium”. For blue cod, and other sharks, skates, and rays, survival from capture on bottom longline was “medium-low”. Red cod survival was “low”, and an “uncertain” outcome was applied to smooth skate and blue moki due to the lack of available knowledge. For species such as spiny dogfish and school shark, the lower range of perceived survival was at least partially a result of the wide range of depths where these species are discarded, which includes deepwater fisheries with larger vessels and potentially different handling practices.

Post-release survival of most species from trawl gear was perceived to be “medium-low” at best, with 90% confidence range either spanning 0.25 up to but less than 0.75, or else between 0.25 and 0.5. Blue cod, red cod, flatfish, and tarakihi were considered in the “low” range, where the 90% confidence range did not exceed 0.25. Survival of both rough and smooth skates in trawl gear was “uncertain”, based on the lack of empirical data for these species and the wide range of estimates for related species in overseas fisheries. Where bottom trawl with a Modular Harvest System cod-end was considered as a separate gear, the lack of available data on this gear type meant survival was considered “uncertain”. For set net, the perceived survival of all species where this gear was considered an important method, was “medium-low”.

The species-method survival confidence ranges presented in this report are based on the best currently available expert knowledge and thorough reviews of the current survival literature; as such, these ranges are unlikely to be improved upon without further investment in release survival research.

Jack mackerels (JMA) support significant commercial fisheries in New Zealand, with over 75% of the total jack mackerel catch taken by trawl fisheries off the west coasts of the North Island and South Island, in JMA 7. Three jack mackerel species are found in New Zealand waters, namely Trachurus declivis, T. murphyi, and T. novaezelandiae.

New Zealand commercial catches of jack mackerels have been recorded under the general code JMA. Therefore species-specific catch information is not available from the fishery data. Estimates of proportions of the three Trachurus species in the catch, based on observer data which includes separate codes for each species, are essential for assessment of the individual stocks.

This report updates the data collected by the New Zealand observer sampling programme from trawl landings of jack mackerels in JMA 7 with the data collected during the 2021–22 fishing year, including estimates of species proportions and sex ratios in the landings, catch-at-length (fork length, cm), and catch-at-age for these species.

Estimated proportions of catch by species based on observer data have historically shown that T. declivis comprises 61–73% of the catch for all statistical areas, followed by T. novaezelandiae at 21–33%, and T. murphyi at 2–8%. In 2021–22, proportions of T. declivis, T. novaezelandiae, and T. murphyi were 77%, 23%, and less than 1%, respectively.

Sampled sex ratios of T. declivis and T. novaezelandiae were close to a sex ratio of 1:1 in the 2021–22 fishing year, and sex ratios for T. murphyi were biased towards females (56%) in 2021–22.

Trachurus declivis and T. novaezelandiae fish in the observer data indicated decreasing proportions of larger and older fish in the commercial catch in recent years, whereas the length and age data for T. murphyi indicated the catch mainly comprised large, older fish, with little evidence of younger fish coming through.