The interaction of the fishery with Endangered, Threatened, or Protected (ETP) species is not considered to be unacceptable, but the impact is cumulative with other fisheries Details about population status and interactions with fisheries are summarized in the MPI's annual environment and biodiversity reviews. For the Hoki fishery, the analysis was updated through the fishing year 2016-2017 (Fisheries New Zealand (FNZ) 2019).
ETP seabirds such as sooty shearwater Puffinus griseus (Near Threatened) (Birdlife International 2017), white capped albatross Thalassarche steadi (Near Threatened) (Birdlife International 2017), Salvin’s Albatross Thalassarche salvini (Vulnerable) (Birdlife International 2017) , Buller’s albatross Thalassarche bulleri (Near Threatened) (Birdlife International 2017) , white-chinned Petrel Procellaria aequinoctialis (Vulnerable) (Birdlife International 2017) are by-catch of the hoki fishery. Management of seabird interactions with New Zealand’s commercial fisheries is driven through the Seabird National Plan of Action (NPOA-Seabirds) (Ministry for Primary Industries 2014). Work is ongoing between MPI and industry to reduce the risk of this fishery to key seabird species. A Vessel Management Plan (VMP) is in place to document fish waste management procedures and reduce the interaction with seabirds (Akroyd et al. 2012). Use of seabird scaring devices for all trawlers >28 m in length, i.e. “paired streamer lines”, “bird baffler” or “warp deflector”, while trawling has been mandatory since 2006. The number of seabirds captured in the hoki fishery has been variable in recent years: in 2014-15, estimated seabird captures in hoki trawl fisheries were 416 (95% c.i. 335-518), the highest in the time series since 2002-03. However, the capture rate, at 2.27 birds per 100 tows observed, was substantially lower than in 2013-14, when total captures were 397 (95% c.i. 335-483), but the capture rate was 3.93. In 2015–2016, estimated seabird captures in hoki trawl fisheries were 238 (95% c.i. 184–311) with a capture rate of 1.4. In the 2016–17 fishing year, 59 seabird captures were observed in hoki trawl fisheries with a capture rate of 2.0 but the estimate of total captures is not yet available (Fisheries New Zealand (FNZ) 2019). The average observed seabird capture rate in hoki trawl fisheries over the last ten years is about 2.36 birds per 100 tows, which is considered a low rate relative to other New Zealand trawl fisheries (Ministry for Primary Industries 2017). Since 2002-03, the six most captured species in hoki fisheries, based on observer data, have been Salvin's, southern Buller's, and NZ white-capped albatross, as well as sooty shearwaters, white-chinned petrels, and cape petrels. The NPOA-Seabirds employs a risk assessment framework to generate quantitative risk scores for seabird species (Ministry for Primary Industries 2016). The hoki fishery is considered to contribute a high level of risk for two of its most captured seabird species, Southern Buller's albatross and Salvin's albatross, which are assessed as being very high-risk species in New Zealand fisheries generally (Ministry for Primary Industries 2017). The mean number of annual potential fatalities in bottom trawl hoki fisheries was estimated at 1540 (95% c.i.: 1140–2050) (Richard et al. 2017), the second highest value. Following the implementation of mandatory mitigation measures (scaring devices), average rates of capture for Salvin's and white-capped albatross (which account for 71% of albatross captures in the hoki fishery) decreased (going from 0.61 and 0.26 to 0.20 and 0.21 per 100 tows respectively, over a 4-year period). The capture rate of white-capped albatross shows a decreasing trend since 2005, while longer-term trends for Salvin's and Southern Buller's albatross captures in trawl fisheries are less definitive (Ministry for Primary Industries 2016) ; (Ministry for Primary Industries 2017). While mitigation devices appear to have been effective in decreasing the rate of warp strikes, net captures recently have been observed to be increasing, which has driven higher rates of capture particularly for smaller species such as sooty shearwater (Akroyd et al. 2016).
Marine mammals are protected under provisions of the Marine Mammals Protection Act (MMPA) 1978, and the MPI’s National Deepwater Plan (NDP) includes objectives to avoid and minimize the capture of marine mammals. The fishery does not interact with dolphins or whales (Boyd, 2011). New Zealand fur seals Arctocephalus forsteri (Least Concern) (Chilvers and Goldsworthy 2015) and New Zealand sea lions Phocarctos hookeri (Endangered) (Chilvers 2017), meanwhile, are identified as incidental catches but are not considered to be threatened by the fishery (Boyd, 2011). Estimated capture rates for fur seal mortalities in the hoki fisheries in the last five years have been below the long term average; in 2015-2016 the mean estimate was 198 animals, equating to a capture rate of 1.2% per fishery tow (Fisheries New Zealand (FNZ) 2019). Captures of sea lions in the hoki fishery are rare, no incidental catches were observed in the last four years (Fisheries New Zealand (FNZ) 2019). Detrimental impacts of the fishery on fur seal populations generally are considered unlikely (Akroyd et al. 2012) ; (Ministry for Primary Industries 2016) though the potential risk to local populations has been noted (Ministry for Primary Industries 2013); (Ministry for Primary Industries 2016). Investigation into population-scale impacts of fishery-related fur seal deaths has been limited by uncertainty about the size of the NZ population and the provenance of animals captured (Ministry for Primary Industries 2016) and until recently, assessment of the overall risk has relied largely on expert opinion and qualitative ecological risk assessment (ERA) (Akroyd et al. 2012) ; (Ministry for Primary Industries 2016) However, a Spatially Explicit Risk Assessment (SEFRA), already applied to New Zealand seabirds, is currently being completed for marine mammals. The fishery-related risk to fur seals is attributed primarily to trawl fisheries targeting hoki and southern blue whiting; and preliminary SEFRA results estimate a cumulative risk ratio across fisheries to be between 0.2-0.6, on a 0.0-5.0 scale, a result that is considered to be consistent with indications that the population size has been increasing in recent years. To improve understanding of the effects of the commercial fisheries on NZ fur seal populations, recommendations include more consistent population data at different geographic scales, genetic work to differentiate between colonies, and increased observer coverage to improve catch estimates. In 2013 the DWG Ltd., in agreement with industry and NGOs, developed a set of Marine Mammal Operational Procedures (MMOP) for mitigating marine mammal bycatch (Ministry for Primary Industries 2013). Active monitoring of interactions is ongoing (Ministry for Primary Industries 2016).
Basking shark Cetorhinus maximus – listed in CITES (Convention on International Trade in Endangered Species of Wild Fauna and Flora) and in the IUCN 2005 Red List as Vulnerable (Fowler 2005) – is occasionally caught as bycatch, although captures have been few since the early 2000s (Fisheries New Zealand (FNZ) 2019). The species has had protected status in New Zealand since 2010. A qualitative risk assessment classified the risk of the impact of commercial fishing in New Zealand as a high risk (Ford et al. 2018). There are no direct mitigation measures, though the DWG Ltd. provides guidance on reporting and safe handling practices to help ensure survival upon release (Deepwater Working Group Ltd. 2014). The New Zealand National Plan of Action for the Conservation and Management of Sharks (NPOA–Sharks) (2013) outlines a set of actions for the conservation and management of sharks, which include review of management categories and protection status, addressing research gaps for high-risk species, monitoring of the implementation of the shark finning ban, and work with fishers to ensure best practice handling and mitigation measures (Ministry for Primary Industries 2016) . Mandatory reporting of catches of protected species serves to monitor interactions. Some research into the interactions between basking sharks and fisheries has been published (e.g. Francis & Sutton (2012) (Ministry for Primary Industries 2017). The 2017-2018 Annual Operational Plan for deepwater fisheries also mentions additional actions, e.g. improving the identification and reporting of sharks (Ministry for Primary Industries 2017). The last MSC reassessment of the fishery made a recommendation to understand the biological status of all pale ghost shark Hydrolagus bemisi (Least Concern (Francis 2003) stocks (Akroyd et al. 2012) . Porbeagle Lamna nasus and school Galeorhinus galeus sharks (both Vulnerable (Stevens et al. 2006) ; (Walker et al. 2006) ) are QMS bycatch species but are not considered to be threatened by the fishery. In addition to species already noted, the second MSC surveillance audit completed in 2014, mentioned other protected species captures reported by observers in the 2012-13 fishing year including dusky dolphin (1) and pilot whale (1) (Akroyd and Pierre, 2014). The current Public Comment Draft Report for the new MSC reassessment for New Zealand hoki, hake and ling trawl fisheries do not attribute any condition or recommendations (O’Boyle et al. 2018).
Many benthic organisms are protected in New Zealand including black corals (all species in the order Antipatharia), Gorgonian corals (all species in the order Gorgonacea), Stony corals (all species in the order Scleractinia), Hydrozoa (hydra-like animals), and Hydrocorals (all species in the family Stylasteridae) (NZ Department of Conservation 2017) . While captures are required by law to be reported, their capture in commercial fisheries is not illegal (Akroyd et al. 2012). While there is a growing body of research on benthic organisms such as corals (Ministry for Primary Industries 2016), robust management has been limited to a degree by lack of knowledge (Akroyd et al. 2012). Hoki fisheries present more observations of catches of protected corals (all species) in comparison with other deepwater fisheries but the total coral bycatch is typically low (O’Boyle et al. 2018). Data from New Zealand seamounts demonstrated a reduction of stony coral cover on trawled seamounts (average in images 0.04–0.03%) in comparison with untrawled seamounts (average in images 12–25%) (Clark et al. 2016).
Hoki represents a majority of the catch in the directed Hoki fishery (Fisheries New Zealand (FNZ) 2019). Other species caught include; Ling, Hake, Javelinfish, Rattails and Spiny dogfish. Combined these species account for the majority of the bycatch by weight but combined were approximately 14% of the catch in the fishing year 2017-2018. Only Ling and Hake were above 3% weight by species (Fisheries New Zealand (FNZ) 2019). Because most of these stocks are quota managed and landed as incidental catch, overall bycatch is not considered problematic (O’Boyle et al. 2018)
Management controls to reduce bycatch and discards include restrictions prohibiting bigger vessels (>45 m) from operating near the coast, agreed catch splits between eastern and western stocks, and Industry Operational Procedures for the hoki trawling fisheries aiming to protect smaller fish (<60 cm) and mitigate bycatch of marine mammals (Deepwater Group (DWG) 2019). Reporting through the Quota Monitoring System (QMS) is in place, and there are cross-comparisons done with at-sea observer data (O’Boyle et al. 2018). Roughly 22% of tows were observed during the most recent updated information, in the fishing year 2016-2017 ((Fisheries New Zealand (FNZ) 2019)
Past assessments have indicated that generally, benthic bycatch is small, except for sponges (Fisheries New Zealand (FNZ) 2019). Baird et al., (2013) mentioned that although all coral orders were represented in the hoki bycatch, about 80% were stony corals (Baird et al., 2013).
In light of an industry proposal, Benthic Protection Areas (BPAs) within New Zealand’s EEZ were closed to bottom trawling (and dredging) in 2007 on a permanent basis (Deepwater Working Group Ltd. 2015; Ministry for Primary Industries 2017). These closures remain in effect for the 2018-2019 fishing year and are part of the regular industry lead initiative to conserver habitat (Deepwater Group (DWG) 2019). There are 17 large BPAs that effectively closed approximately 30% of the New Zealand EEZ (Ministry for Primary Industries 2014), and cover 52% of all seamounts and 88% of hydrothermal vents (New Zealand Department of Conservation and Ministry of Fisheries 2005, Ministry for Primary Industries 2017a, Ministry for Primary Industries 2013a, Ministry for Primary Industries 2014). The Hoki Operational Procedure further closes areas where juveniles are known to occur (Deepwater Group (DWG) 2019). However, recent studies have been assessing New Zealand's existing MPAs and considered that existing MPAs are inefficient in protecting a representative range of biodiversity (Geange et al. 2017).
Recently an MSC habitat certification condition, raised during the initial 2012 assessment, was considered resolved. This condition centered around the reduction of habitat impacts, and habitat management. During the most recent recertification, this condition was found to have been met (O’Boyle et al. 2018). Overall habitat impacts are thought to be low for this fishery, and what little impact there is, well managed (O’Boyle et al. 2018).
Given their large biomass, hoki are a key component of the upper slope (200-800 m), and the importance of understanding of prey-predator relationships between hoki and other species is noted, particularly since substantial changes in the biomass of hoki have taken place since the fishery began (Fisheries New Zealand (FNZ) 2019). A past study (Anderson and Smith 2005 in (Ministry for Primary Industries 2016) estimated annual hoki discards in the hoki fishery to be between 600-2,100 tonnes; an amount that is considered large enough to have potential impacts on the diets of scavenging species (Forman and Dunn 2012 in (Ministry for Primary Industries 2016a). Hoki are prey to several piscivores, particularly hake but also stargazers, smooth skates, several deepwater shark species, and ling; (Dunn et al 2009a in Fisheries New Zealand 2018). The proportion of hoki in the diet of hake averages 38% by weight, and has declined since 1992 (Dunn & Horn 2010 in Fisheries New Zealand 2018), possibly because of a decline in the relative abundance of hoki on the Chatham Rise between 1991 and 2007. Information on the size and recruitment stage of hoki eaten by predators is lacking and could be an important factor with regard to fishery interaction and potential for competition (Ministry for Primary Industries 2017). Tuck et al. (2009) focused study on the ecosystem processes in Chatham Rise and Sub- Antarctic area showed some evidence of a change in ecosystem indicators over time. They reported an increase of evenness or reduction in diversity. However, there was no evidence that species were being lost from the food-web (O’Boyle et al. 2018).