Shark vertebrae and their centra (vertebral bodies) are high-performance structures able to survive millions of cycles of high amplitude strain despite lacking a repair mechanism for accumulating damage. Shark centra consist of mineralized cartilage, a biocomposite of bioapatite (bAp), and collagen, and the nanocrystalline bAp's contribution to functionality remains largely uninvestigated. Using the multiple detector energy-dispersive diffraction (EDD) system at 6-BM-B, the Advanced Photon Source, and 3D tomographic sampling, the 3D functionality of entire centra were probed. Immersion in ethanol vs phosphate-buffered saline produces only small changes in bAp d-spacing within a great hammerhead centrum. EDD mapping under in situ loading was performed an entire blue shark centrum, and 3D maps of bAp strain showed the two structural zones of the centrum, the corpus calcareum and intermedialia, contained opposite-signed strains approaching 0.5%, and application of ~8% nominal strain did not alter these strain magnitudes and their spatial distribution.

The parasitic barnacle, Anelasma squalicola, is a rare and evolutionary fascinating organism. Unlike most other filter-feeding barnacles, A. squalicola has evolved the capability to uptake nutrient from its host, exclusively parasitizing deepwater sharks of the families Etmopteridae and Pentanchidae. The physiological mechanisms involved in the uptake of nutrients from its host are not yet known. Using stable isotopes and elemental compositions, we followed the fate of nitrogen, carbon and sulphur through various tissues of A. squalicola and its host, the Southern lanternshark Etmopterus granulosus, to better understand the trophic relationship between parasite and host. Like most marine parasites, A. squalicola is lipid-rich and clear differences were found in the stable isotope ratios between barnacle organs. It is evident that the deployment of a system of ‘rootlets’, which merge with host tissues, allows A. squalicola to draw nutrients from its host. Through this system, proteins are then rerouted to the exterior structural tissues of A. squalicola while lipids are used for maintenance and egg synthesis. The nutrient requirement of A. squalicola was found to change from protein-rich to lipid-rich between its early development stage and its definitive size.

Recognition of decompression syndrome-related pathology (in the form of avascular necrosis) reveals diving behaviour in mosasaurs. Macroscopic and radiologic examination was performed to identify linear bone death characteristic of avascular necrosis in vertebrae from the major North American and European collections. This survey of mosasaurs extends throughout most of their geographic and stratigraphic range and includes examples across their diversity.

Avascular necrosis was invariably present in Platecarpus coryphaeus and P. ictericus, Tylosaurus proriger, Mosasaurus lemonnieri and M. conodon, Plioplatecarpus houzeaui and Pl. primaevus, Prognathodon giganteus, Hainosaurus bernardi and an as yet unnamed Antarctic mosasaur. The frequency of occurrence in a given genus was independent of geography, present equally in European and North American and in the Niobara and Selma chalks. It was invariably absent from Clidastes propython and C. liodontus, Ectenosaurus, Halisaurus and Kolposaurus.

The bone pathology, avascular necrosis, has a characteristic distribution in seven genera and thirteen species of mosasaurs and is absent in five genera and seven species. It segregated according to diving habits, uniformly present in supposed deep divers and uniformly absent in the shallow-habitat group.

To address growing concern over the effects of fisheries non-target catch on elasmobranchs worldwide, the accurate reporting of elasmobranch catch is essential. This requires data on a combination of measures, including reported landings, retained and discarded non-target catch, and post-discard survival. Identification of the factors influencing discard versus retention is needed to improve catch estimates and to determine wasteful fishing practices. To do this, retention rates of elasmobranch non-target catch in a broad subset of fisheries throughout the world were compared by taxon, fishing country, and gear. A regression tree and random forest analysis indicated that taxon was the most important determinant of retention in this dataset, but all three factors together explained 59% of the variance. Estimates of total elasmobranch removals were calculated by dividing the Food and Agriculture Organization of the United Nations (FAO) global elasmobranch landings by average retention rates, and suggest that total elasmobranch removals may exceed FAO reported landings by as much as 400%. This analysis is the first effort to directly characterize global drivers of discards for elasmobranch non-target catch. The results highlight the importance of accurate quantification of retention and discard rates to improve assessments of the potential impacts of fisheries on these species.

A scalloped hammerhead Sphyrna lewini was observed opportunistically from a remotely operated vehicle 1 m off the seabed at 1042 m depth, during hydrocarbon exploration activities in the Ruvuma Basin off Tanzania. The observation, which occurred during night hours, is the deepest accurately recorded for this species and the first deep-water record for the Indian Ocean. The record adds support for the occurrence in deep water during night hours being a widespread and possibly common behaviour in this species, and further expands a small but growing literature that meso- and bathypelagic environments may be of greater importance to elasmobranchs previously considered to be primarily epipelagic.

The threatened grey nurse shark (Carcharias taurus) is reported for the first time from oceanic coral reefs in the Timor Sea. Generally known from temperate and subtropical coastal reef habitats, this species was encountered by Indonesian traditional fishers on oceanic coral reefs in an area of the Australian Exclusive Economic Zone known as the 1974 MoU Box, some 200 km from the Australian mainland. The presence of C. taurus on these remote tropical reefs bears important management implications, including the species’ protected status in Australian waters and the challenges of regulating catches in areas permitted for traditional Indonesian fishing.

Observations, photographs, and video footage of a 337 cm total length female smalltooth sand tiger shark, Odontaspis ferox made at a depth of 348 m on the northern slope of San Ambrosio Island in the Desventuradas Islands (26°19.456′S 79°52.281′W) on 25 February 2013 represent not just the first record of this species in Chilean waters, but the first in the entire south-eastern Pacific Ocean, marking a tremendous range extension of this species. We also summarize the few known occurrences of this species along the Pacific and Atlantic coasts of South America.

There is growing awareness that small-scale fisheries may have large impacts on threatened marine fauna. Bycatch of small cetaceans by the Peruvian small-scale driftnet fleet results in the deaths of thousands of animals annually. We sought to assess the effectiveness of acoustic alarms (pingers) for reducing the incidental capture of dolphins and porpoises by this fleet. Forty-three experimental trips (156 fishing sets) and 47 control trips (195 fishing sets) out of Salaverry Port, northern Peru, were observed from April 2009 to August 2011. Twenty-two percent of control sets captured small cetaceans (67 individuals) and 16% of experimental sets had captures of small cetaceans (33 individuals). The bycatch rate of experimental sets was 0.50 individuals km−2h−1, whereas for control sets the rate was 0.80 individuals km−2h−1. This 37% reduction in bycatch rate suggests that pingers may be effective in reducing the bycatch of small cetaceans in this fishery. Catch rates of the fishery's target shark and ray species were unchanged. Given the vast size of this fishery and its current levels of bycatch of small cetaceans (> 10,000 individuals annually), even the modest declines in bycatch we observed could result in reductions in mortality of hundreds or thousands of small cetaceans per annum. Challenges, including increased costs, to large-scale utilization of pingers have yet to be overcome. The harpooning of dolphins for use as bait will also need to be addressed for further reductions in dolphin and porpoise bycatch and mortality to be achievable.

The mandarin dogfish, Cirrhigaleus barbifer, is the only species in this genus found in Western Australia, and represents a significant range extension and first record in Australia. Most Cirrhigaleus sharks are clearly separable from other squalid sharks by the presence of conspicuous barbels on the anterior nasal flaps. Cirrhigaleus barbifer may be distinguished from its close relative C. australis by the structure of the CO1 gene and key measurements. In addition, this is only the second record of a gravid female of C. barbifer, with pups in an advanced stage of development. New data on the reproductive biology and range of C. barbifer are included.

Twelve parasitic copepod species representing two families were opportunistically recorded from the skin of 13 elasmobranch species captured in the coastal waters of Oman. New host records include Alebion carchariae, Pandarus smithii and Pandarus cranchii on Carcharhinus amboinensis; Echthrogaleus denticulatus on Alopias superciliosus and Sphyrna lewini; Pandarus carcharhini on Carcharhinus altimus; Pseudopandarus longus on Carcharhinus sorrah; Caligus dasyaticus on Glaucostegas halavi. Previous records of Pseudopandarus australis are limited to the Pacific Ocean, and its occurrence in the northern Indian Ocean represents a large range extension.

The crocodile shark, Pseudocarcharias kamoharai previously unknown from the Arabian Sea of India is reported from the south-western coast (Kerala). The specimen is described and figured.

The bigeye thresher, Alopias supercilious,is commonly caught as bycatch in pelagic longline fisheries targetingswordfish. Little information is yet available on the biology ofthis species, however. As part of an ongoing study, observers sentaboard fishing vessels have been collecting set of information thatincludes samples of vertebrae, with the aim of investigating ageand growth of A. supercilious. A total of 117 specimenswere sampled between September 2008 and October 2009 in the tropicalnortheastern Atlantic, with specimens ranging from 101 to 242 cmfork length (FL) (176 to 407 cm total length). The A. supercilious vertebraewere generally difficult to read, mainly because they were poorlycalcified, which is typical of Lamniformes sharks. Preliminary trialswere carried out to determine the most efficient band enhancementtechnique for this species, in which crystal violet section stainingwas found to be the best methodology. Estimated ages in this sampleranged from 2 to 22 years for females and 1 to 17 years for males.A version of the von Bertalanffy growth model (VBGF) re-parameterisedto estimate L0, and a modified VBGF using a fixed L0 were fittedto the data. The Akaike information criterion (AIC) was used tocompare these models. The VBGF produced the best results, with thefollowing parameters: Linf = 293 cm FL, k = 0.06 y–1 and L0 = 111 cmFL for females Linf = 206 cm FL, k = 0.18 y–1 and L0 = 93 cm FLfor males. The estimated growth coefficients confirm that A. supercilious isa slow-growing species, highlighting its vulnerability to fishingpressure. It is therefore urgent to carry out more biological researchto inform fishery managers more adequately and address conservationissues.

The tooth of a tiger shark, perforated to make a pendant, was lost in New Ireland, New Guinea between 39500 and 28000 years ago. The author argues that this has to be the work of anatomically modern humans, and implies the use of symbolic language not only across the former continent of Sahul, but also Eurasia.

Analysis of ecological baseline data collected for key resource species within the Galapagos Marine Reserve indicates that variation in animal density associated with the location of fully protected zones can be comparable to protected area effects. Even with a high level of interspersion between conservation, tourism and fishing management zones, major differences in densities of economically important species were evident between zone types prior to enforcement of fishing restrictions. Densities of the most valuable fishery resource, sea cucumbers, were three times higher in zones that remained open to fishing compared to ‘no-take’ conservation zones, and densities of sharks were five times higher in tourism zones than fishing or conservation zones. These results highlight bias in the socio-political processes that can accompany selection of marine protected areas, where fishers attempt to minimize perceived impacts on their livelihood by locating large protected zones in resource-poor areas, and tourism operators and sport divers argue for protection of areas containing atypically-interesting features. Bias in the location of fully protected zones can seriously confound ‘control-impact’ field investigations when data prior to prohibitions on fishing are lacking, including meta-analyses, which are dominated by such potentially systematically biased studies.