Natural history footage provides new reef fish biodiversity information for a pristine but rarely visited archipelago.

There remain parts of our planet that are seldom visited by humans, let alone scientists. In such locations, crowd-sourced or citizen scientist data can be critical in describing biodiversity and detecting change. Rangitahua, the Kermadec Islands, are 750 km from the nearest human-habitation. Although our knowledge of this near pristine location has increased with recent biodiversity expeditions, we still lack comprehensive understanding of the marine biodiversity surrounding the islands. In 2015, professional underwater videographers were commissioned to produce a nature documentary focused on Rangitahua's reefs. We strategically surveyed the raw documentary video and examined how biodiversity estimates differed from traditional scientific surveys. We uncovered three new fish species records for Rangitahua, extending the known distribution for each species, two of which are also new records for New Zealand waters. Comparison of documentary video footage with scientific survey methods showed that estimates of reef fish species richness from the documentary video were similar to stationary surveys, but lower than non-stationary surveys. Moreover, all survey methods, including documentary video, captured different fish assemblages, reflecting each method's particular bias. Overall, we provide a proof-of-concept for how collaborations between scientists and professional natural historians, such as videographers and photographers, can provide valuable biodiversity information.

Global spatial risk assessment of sharks under the footprint of fisheries.

Effective ocean management and the conservation of highly migratory species depend on resolving the overlap between animal movements and distributions, and fishing effort. However, this information is lacking at a global scale. Here we show, using a big-data approach that combines satellite-tracked movements of pelagic sharks and global fishing fleets, that 24% of the mean monthly space used by sharks falls under the footprint of pelagic longline fisheries. Space-use hotspots of commercially valuable sharks and of internationally protected species had the highest overlap with longlines (up to 76% and 64%, respectively), and were also associated with significant increases in fishing effort. We conclude that pelagic sharks have limited spatial refuge from current levels of fishing effort in marine areas beyond national jurisdictions (the high seas). Our results demonstrate an urgent need for conservation and management measures at high-seas hotspots of shark space use, and highlight the potential of simultaneous satellite surveillance of megafauna and fishers as a tool for near-real-time, dynamic management.

Introgressive hybridisation between two widespread sharks in the east Pacific region.

With just a handful of documented cases of hybridisation in cartilaginous fishes, shark hybridisation remains poorly investigated. Small amounts of admixture have been detected between Galapagos (Carcharhinus galapagensis) and dusky (Carcharhinus obscurus) sharks previously, generating a hypothesis of ongoing hybridisation. We sampled a large number of individuals from areas where the species co-occur (contact zones) across the Pacific Ocean and used both mitochondrial and nuclear-encoded SNPs to examine genetic admixture and introgression between the two species. Using empirical analytical approaches and simulations, we first developed a set of 1873 highly informative SNPs for these two species to evaluate the degree of admixture between them. Overall, results indicate a high discriminatory power of nuclear SNPs (FST = 0.47, p < 0.05) between the two species, unlike mitochondrial DNA (ΦST = 0.00 p > 0.05), which failed to differentiate these species. We identified four hybrid individuals (∼1%) and detected bi-directional introgression between C. galapagensis and C. obscurus in the Gulf of California along the east Pacific coast of the Americas. We emphasize the importance of including a combination of mtDNA and diagnostic nuclear markers to properly assess species identification, detect patterns of hybridisation, and better inform management and conservation of these sharks, especially given the morphological similarities within the genus Carcharhinus.

First record of the sicklefin devilray Mobula tarapacana (Myliobatiformes: Mobulidae) from Australian waters.

The sicklefin devilray Mobula tarapacana (Philippi, 1892) is one of the largest and least known mobulids (Compagno & Last 1999; Couturier et al. 2012). Collections, fisheries bycatch data and visual records suggest it is primarily oceanic, with a circumglobal tropical and warm temperate distribution (Notarbartolo-di-Sciara 1987; Compagno & Last 1999; Gadig & Sampaio 2002; White et al. 2006a, b; Weir et al. 2012; Sobral 2013; Tomita et al. 2013). In the Pacific Ocean it has been recorded from Chile, Gulf of California, Japan, Taiwan, South China Sea and Indonesia (Compagno & Last 1999; White et al. 2006b; Couturier et al. 2012; Tomita et al. 2013).

Misidentification of Carcharhinus galapagensis (Snodgrass & Heller, 1905) in the Southwest Pacific Ocean.

Although primarily a coral reef species the grey reef shark Carcharhinus amblyrhynchos has been recorded from a number of subtropical oceanic islands and reefs in the Southwest Pacific Ocean. Examination of all nominal C. amblyrhynchos voucher material collected from Lord Howe Island, Elizabeth and Middleton Reefs and Norfolk Island resulted in the re-identification of these specimens as Galapagos sharks, C. galapagensis. As C. amblyrhynchos superficially resembles C. galapagensis visual records of C. amblyrhynchos from Elizabeth and Middleton Reefs and the Kermadec Islands cannot be substantiated without voucher material. Carcharhinus amblyrhynchos therefore appears to be confined to waters north of about 25o S in the Southwest Pacific. Precaudal vertebral counts should be used to confirm the identification of nominal C. amblyrhynchos specimens that have an interdorsal ridge.

Evaluation of biogeographic classification schemes for conservation planning: application to New Zealand's coastal marine environment.

For many regions worldwide, multiple and often contrasting biogeographic classifications exist that are derived from a variety of taxa and techniques. This presents a challenge for managers who must choose appropriate large-scale spatial frameworks for systematic conservation planning. We demonstrate how systematically collected community data can be used to evaluate existing biogeographic classifications, identify the most appropriate metric for biogeographic patterns seen in other taxonomic groups, and develop an independent biogeographic classification scheme for systematic conservation planning. We evaluated 6 existing biogeographic classifications for New Zealand's nearshore marine environment with community-similarity metrics derived from abundance and presence-absence data for macroalgae (107 species) and mobile macroinvertebrates (44 species). The concordance between community metrics and the previous classifications was high, as indicated by a high multivariate classification success (CS) (74.3-98.3%). Subsequently, we carried out an independent classification analysis on each community metric to identify biogeographic units within a hierarchical spatial framework. The classification derived from macroalgal presence-absence data achieved the highest CS and could be used as a mesoscale classification scheme in which 11 regional groupings (i.e., bioregions) (CS = 73.8-84.8%) are nested within northern and southern biogeographic provinces (CS = 90.3-98.7%). These techniques can be used in systematic conservation planning to inform the design of representative and comprehensive networks of marine protected areas through evaluation of the current coverage of marine reserves in each bioregion. Currently, 0.22% of the territorial sea around mainland New Zealand is protected in no-take marine protected areas in which 0-1.5% of each bioregion represented.