Implications for the conservation of deep-water corals in the face of multiple stressors: A case study from the New Zealand region.

The waters around New Zealand are a global hotspot of biodiversity for deep-water corals; approximately one sixth of the known deep-water coral species of the world have been recorded in the region. Deep-water corals are vulnerable to climate-related stressors and from the damaging effects of commercial fisheries. Current protection measures do not account for the vulnerability of deep-water corals to future climatic conditions, which are predicted to alter the distribution of suitable habitat for them. Using recently developed habitat suitability models for 12 taxa of deep-water corals fitted to current and future seafloor environmental conditions (under different future climatic conditions: SSP2 - 4.5 and SSP3 - 7.0) we explore possible levels of spatial protection using the decision-support tool Zonation. Specifically, we assess the impact of bottom trawling on predictions of current distributions of deep-water corals, and then assess the effectiveness of possible protection for deep-water corals, while accounting for habitat refugia under future climatic conditions. The cumulative impact of bottom trawling was predicted to impact all taxa, but particularly the reef-forming corals. Core areas of suitable habitat were predicted to decrease under future climatic conditions for many taxa. We found that designing protection using current day predictions alone, having accounted for the impacts of historic fishing impacts, was unlikely to provide adequate conservation for deep water-corals under future climate change. Accounting for future distributions in spatial planning identified areas which may provide climate refugia whilst still providing efficient protection for current distributions. These gains in conservation value may be particularly important given the predicted reduction in suitable habitat for deep-water corals due to bottom fishing and climate change. Finally, the possible impact that protection measures may have on deep-water fisheries was assessed using a measure of current fishing value (kg km-2 fish) and future fishing value (predicted under future climate change scenarios).

Predicting the effects of climate change on deep-water coral distribution around New Zealand-Will there be suitable refuges for protection at the end of the 21st century?

Deep-water corals are protected in the seas around New Zealand by legislation that prohibits intentional damage and removal, and by marine protected areas where bottom trawling is prohibited. However, these measures do not protect them from the impacts of a changing climate and ocean acidification. To enable adequate future protection from these threats we require knowledge of the present distribution of corals and the environmental conditions that determine their preferred habitat, as well as the likely future changes in these conditions, so that we can identify areas for potential refugia. In this study, we built habitat suitability models for 12 taxa of deep-water corals using a comprehensive set of sample data and predicted present and future seafloor environmental conditions from an earth system model specifically tailored for the South Pacific. These models predicted that for most taxa there will be substantial shifts in the location of the most suitable habitat and decreases in the area of such habitat by the end of the 21st century, driven primarily by decreases in seafloor oxygen concentrations, shoaling of aragonite and calcite saturation horizons, and increases in nitrogen concentrations. The current network of protected areas in the region appear to provide little protection for most coral taxa, as there is little overlap with areas of highest habitat suitability, either in the present or the future. We recommend an urgent re-examination of the spatial distribution of protected areas for deep-water corals in the region, utilising spatial planning software that can balance protection requirements against value from fishing and mineral resources, take into account the current status of the coral habitats after decades of bottom trawling, and consider connectivity pathways for colonisation of corals into potential refugia.

A review of New Zealand and southeast Australian echinothurioids (Echinodermata: Echinothurioida)-excluding the subfamily Echinothuriinae-with a description of a new species of Tromikosoma.

An examination of a large collection of echinothurioid echinoids (excluding the subfamily Echinothuriinae Thomson) from museum collections in New Zealand and Australia has expanded the known diversity of the group in New Zealand from three species in two genera to seven species in five genera, and revealed a new species in the genus Tromikosoma Mortensen.New records for New Zealand and Australia are reported for Sperosoma obscurum Agassiz and Clark, 1907 and S. nudum Shigei, 1978 and new records for New Zealand are reported for Tromikosoma australe (Koehler, 1922) and Kamptosoma asterias (A. Agassiz, 1881). Tromikosoma rugosum sp. nov., remarkable for its unusual wrinkled appearance and exceedingly thin test, is described from deep water in the northeast of New Zealand. No evidence for the existence of Phormosoma rigidum A. Agassiz, 1881 as a species separate from P. bursarium A. Agassiz, 1881 was found, and synonymy with P. bursarium is proposed.Previous records of these echinoid species were rare, as they live mostly in deep water (>1000 m), and three species were previously known from the type material alone. Tromikosoma rugosum sp. nov. now falls into that category, but new material of the other species greatly expands both the number of known records and their geographical distribution. The majority of these new records are from the New Zealand region, with several additional records from south-east Australia.An updated key to the echinothurioids of New Zealand is provided.

A review of New Zealand and southeast Australian echinothuriinids (Echinodermata: Echinothuriidae) with descriptions of seven new species.

Examination of a large collection of echinothurioid echinoids from museum collections in New Zealand and Australia revealed six new species in the genus Araeosoma (A. bidentatum sp. nov., A. migratum sp. nov., A. anatirostrum sp. nov., A. tertii sp. nov., A. leppienae sp. nov., and A. bakeri sp. nov.) and one in the genus Hapalosoma (H. amynina sp. nov.), while the recorded presence of A. coriaceum in northwest New Zealand was found to be incorrect. Several of the species described are rarely collected, their distribution being strongly associated with seamount type habitat in a relatively narrow depth range. The majority of the records of these new species are from the New Zealand region, with a strong centre of diversity revealed among the seamounts of the Bay of Plenty. The new species are clearly distinguished from known forms by characters of their pedicellariae, spines, coronal plate structure, colouring, and tuberculation. A key to the Echinothuriinae of the region is included.

Deep-sea fish distribution varies between seamounts: results from a seamount complex off New Zealand.

Fish species data from a complex of seamounts off New Zealand termed the "Graveyard Seamount Complex' were analysed to investigate whether fish species composition varied between seamounts. Five seamount features were included in the study, with summit depths ranging from 748-891 m and elevation from 189-352 m. Measures of fish species dominance, rarity, richness, diversity, and similarity were examined. A number of factors were explored to explain variation in species composition, including latitude, water temperature, summit depth, depth at base, elevation, area, slope, and fishing effort. Depth at base and slope relationships were significant with shallow seamounts having high total species richness, and seamounts with a more gradual slope had high mean species richness. Species similarity was modelled and showed that the explanatory variables were driven primarily by summit depth, as well as by the intensity of fishing effort and elevation. The study showed that fish assemblages on seamounts can vary over very small spatial scales, in the order of several km. However, patterns of species similarity and abundance were inconsistent across the seamounts examined, and these results add to a growing literature suggesting that faunal communities on seamounts may be populated from a broad regional species pool, yet show considerable variation on individual seamounts.