Genetic diversity is critical to long-term survival of species but can be eroded by population declines driven by human pressures. Temporal genetic monitoring of threatened species can reveal changes in genetic diversity over time, providing key data for conservation. Specimens from natural history collections were used to assess changes in genetic diversity in the Critically Endangered largetooth sawfish (Pristis pristis). Historically, P. pristis had a circumtropical range, but following massive declines it is now primarily found in Australia, with limited depleted populations elsewhere. Genetic data (815-bp of the mitochondrial control region) from 87 specimens from across its historical range revealed significant population structure, with the Indo-West Pacific and the Atlantic/Eastern Pacific comprising distinct lineages. Comparisons between historical (approx. 1878-2000) and contemporary populations (2001-2014) revealed genetic diversity loss, with only six of 35 historical haplotypes represented in contemporary populations. Most of the lost haplotypes were from the Atlantic/Eastern Pacific, which is at risk of further genetic erosion. Genetic diversity in Australia appears stable since the 1960s, while Brazil showed a marked loss, despite contemporary estimates similar to those in Australia. These findings highlight the need to conserve remaining genetic diversity in P. pristis, emphasizing the importance of securing a stronghold in the Atlantic/Eastern Pacific.

Zoological specimens held in natural history collections are an invaluable resource for studying biodiversity and providing baseline data for species of conservation concern. Confidence in collection metadata associated with specimens is needed to ensure certainty in scientific studies. These collection metadata may contain inaccuracies or missing information, which can occur during documentation or from anecdotal accounts. The few standardized methods available to assess confidence do not cater to a wide array of specimen types which may explain why many studies use unspecified or subjective methods, or neglect to address confidence altogether. Here, we developed a standardized method using flowcharts to rank confidence in collection location and date data for a wide array of specimens incorporating a minimum standard to determine which specimens should be included in a study. We demonstrated the utility of this method in a case study using Largetooth Sawfish Pristis pristis specimens (i.e., dried rostra) to assess their historical global range. As more stringent standards were applied, the pool of specimens decreased, but the confidence in their associated collection metadata increased. This novel method can increase transparency, certainty, comparability, and replicability of studies using specimens. This can reduce subjectivity, leading to more accurate baselines for conservation management.

For globally threatened species, patchy data pose challenges in both establishing historical baselines and assessing current distributions. In the case of sawfishes, much previous research has relied on amputated trophy rostra or historical photographs to fill data gaps in distribution and population estimates. However, the established morphometric models that allow the estimation of total length from rostra are restricted by the data available to generate them, with many constructed solely from juvenile morphometric data, and robust error testing rarely performed. This study generates an independent dataset from citizen science photographs and field measurements, incorporating sawfishes of all life history stages, to test the robustness of previously proposed models for the four Indo-Pacific sawfish species. Rostrum-to-length morphometric models (RLMs) were confirmed for Pristis clavata and Pristis pristis, and a new model was proposed for Pristis zijsron. A key source of error in previous RLMs for Anoxypristis cuspidata was identified as changing rostrum morphology with body size, but there were insufficient measurements in the present dataset to propose a new robust model for this species. This study highlights the problems associated with extrapolating total lengths of animals beyond the size bounds used to produce the original model. For historically exploited species like sawfishes, which are often represented in collections by trophies alone, these methods outline a critical step prior to use in further ecological study.

Wedgefishes (Rhinidae) are threatened by unsustainable fishing globally, and especially in the Southwest Indian Ocean (SWIO), due to their high-value fins in the shark trade. The whitespotted wedgefish Rhynchobatus djiddensis and the bottlenose wedgefish R. australiae are both classified as Critically Endangered on the IUCN Red List of Threatened Species, yet a lack of species-specific knowledge and taxonomic uncertainty still exists within this genus. Genetic approaches aid in taxonomic classification and identifying distinct populations for targeted conservation. Morphological specimen identification of samples (n = 189) collected across the SWIO was confirmed based on the cytochrome oxidase c subunit I (COI) and/or nicotinamide adenine dehydrogenase subunit 2 (ND2) gene regions. The genetic diversity and population structure within and between species and sampling locations were investigated using a dual marker approach: (1) 2 concatenated mitochondrial gene regions, namely COI and the control region (n = 117), and (2) 9 nuclear microsatellite markers (n = 146). The overall genetic diversity was moderate, with an indication that different evolutionary forces are at play on a mitochondrial versus nuclear level. The 2 species were delineated based on both marker types, and for R. djiddensis, the sampling locations of South Africa and Mozambique were genetically homogeneous. For R. australiae, significant differentiation was found between sampling locations, with Madagascar and Tanzania being genetically the most similar. This information provides critical insights into the distribution range and population structure of the whitespotted wedgefish species complex that can support the sustainable management of wedgefishes.

1. North-western Australia is considered a refuge to several highly threatened elasmobranch species, but there has been little research effort targeting lesser known, large-bodied rhino rays. This study identified 2,343 records of globally threatened rays of the order Rhinopristiformes from the Pilbara region of Western Australia, with a focus on the Ningaloo Coast World Heritage Area and adjacent Exmouth Gulf. 2. Occurrence data were compiled from various sources including commercial fishing reports (35%), citizen science records (34%), targeted scientific surveys (30%) and published literature (1%). The region was inhabited by all of Australia's Pristidae (four sawfish species), all of Australia's Rhinidae (three wedgefish species) and the sole Australian representative of the Glaucostegidae (giant shovelnose ray). Of the 2,343 records, similar to 49% were sawfishes, while giant guitarfish and wedgefishes contributed to similar to 33% and 18% of records, respectively. 3. The Exmouth Gulf appears to be a globally important refuge and pupping area for green sawfish (Pristis zijsron) which was the most commonly encountered pristid. Bottlenose wedgefish (Rhynchobatus australiae) were the most commonly identified rhinid, with less frequent encounters of shark rays (Rhina ancylostoma) and eyebrow wedgefish (Rhynchobatus palpebratus). The Ningaloo Coast World Heritage Area and adjacent Exmouth Gulf host all life stages of giant shovelnose ray (Glaucostegus typus). 4. The combined use of several data sources has highlighted the study region as a 'lifeboat' for these globally threatened large-bodied rays. These data are essential in creating effective conservation and management plans in this globally important refuge, and are highly relevant to global conservation initiatives.

In this study, single nucleotide polymorphisms were used to investigate kinship and philopatry for the Critically Endangered green sawfish, Pristis zijsron, in Western Australia. Sampling was conducted in an important nursery area: the Ashburton River estuary and adjacent tidal creeks. Kinship was inferred from the genotypes of 104 sawfish sampled between 2011 and 2014 (n = 31), and 2020 and 2022 (n = 73). The total number of dams contributing across all sites and time periods was estimated to be between 50 and 56. Fifty-two full sibling dyads, 90 half sibling dyads and 72 third-degree dyads were detected, involving 58, 67, and 46 P. zijsron, respectively. Of these, 34 half sibling dyads were related maternally and 56 related paternally, including multiple maternal and paternal half siblings pupped in different years, suggesting both female and male philopatry. Catch data indicated that two groups of maternal half siblings were littermates, demonstrating multiple paternity. A high degree of relatedness was found across the study area, with 88% of P. zijsron related to at least one other individual up to the third-degree. Evidence for female philopatry in P. zijsron highlights the importance of protecting nursery areas for this species. The occurrence of philopatric behaviour in male and female P. zijsron suggests that dispersal might be limited in both sexes of this species, highlighting the need to investigate the amount of genetic diversity and incidence of inbreeding within remaining populations.

Context In this study, single-nucleotide polymorphisms (SNPs) were used to investigate kinship for the green sawfish (Pristis zijsron). Aims To examine the relatedness of P. zijsron across an expansive coastline in Western Australia. Methods Sampling was conducted between the Fitzroy River estuary and Bay of Rest in the eastern Indian Ocean (north-western Australia) between 2003 and 2022. SNPs were generated from tissues collected from 137 live and 1 recently deceased P. zijsron. Key results Overall, 62 individual P. zijsron were assigned to 25 litters of full siblings, with litter sizes ranging from 2 to 5 pups, and 76 P. zijsron individuals were assigned to 96 half sibling pairwise relationships. Four pairs of half siblings were captured more than 500 km and born at least 6 years apart, including one pair of neonates captured similar to 870 km and 8 years apart, in the Ashburton River estuary (Pilbara) and Cable Beach (Broome). Furthermore, a pair of full-sibling pups (i.e. young of the year) caught at Cape Keraudren (Pilbara) in 2008 were half siblings of a pup caught in the Ashburton River in 2014. Conclusions This study provides evidence of long-distance, likely parental, movement of P. zijsron. Implications Dispersal of P. zijsron over large spatial scales indicates that populations could be replenished from elsewhere should they experience a decline, thereby reducing the risk of localised extinction for this species.

Although almost 990 species of bony fish (Osteichthyes) actively produce sounds, evidence for active sound production by elasmobranchs—sharks, rays, and skates—is scarce (Looby et al., 2022). To date, there have been only 27 examinations of sound production by elasmobranchs (Looby et al., 2022), and of the 13 recorded occurrences, the majority have been passive sounds associated with feeding (e.g., shell crushing; Ajemian et al., 2021). The only confirmed case of active sound production occurred when captive cownose rays Rhinoptera bonasus produced short, sharp clicks under duress, that is, forceful prodding (Fish & Mowbray, 1970). Two further examples of "active" sound production have been documented—"crunching" sounds with chewing and "mumbling" after ingestion in a captive common stingray Dasyatis pastinaca and "rumbles" when grabbing food by a captive picked dogfish Squalus acanthias (Shishkova, 1958)—but these were both associated with feeding and are less convincing. There have been no confirmed examples of active sound production by elasmobranchs in the wild, despite attempts to record the behavior outside of captive settings. Although there are some anecdotal reports, they remain unproven or are given without sources. Bass and Rice (2010), for example, reported that "stingrays have been anecdotally documented to grind their teeth as an audible defence warning signal," without providing a reference for this statement. By comparison, the hearing capabilities of elasmobranchs have received much more attention (Mickle et al., 2020; Myrberg, 2001). Elasmobranchs are most sensitive to low-frequency sounds between 40 and 1500 Hz, with peak sensitivities between 200 and 400 Hz, but audiograms have only been produced for 10 species (Chapuis & Collin, 2022). There is more evidence relating to behavioral responses to sounds. Many sharks are attracted to certain sounds, like those of struggling prey, and can change their behaviors in response to such sounds (Gardiner et al., 2012). Other sounds, such as the vocalizations of killer whales, Orcinus orca, reportedly repulse and cause a fleeing response in epipelagic sharks, which could fall prey to these odontocetes (Chapuis et al., 2019; Myrberg, 2001). Similarly, in some shark species an unexpected sound or the sudden increased intensity of a sound can result in rapid withdrawal from the sound source (Klimley & Myrberg, 1979; Myrberg, 2001; Myrberg et al., 1978). Sound may also elicit less obvious responses, for example, the southern stingray Hypanus americanus has been shown to alter its swimming behavior (i.e., resting less, increasing swimming activity, and breaching the surface more often) in response to certain sounds (Mickle et al., 2020). Though it is clear that elasmobranchs can hear and many can also respond to sound in various ways, hearing capacity is not necessarily linked to the ability to produce acoustic sound (Mélotte et al., 2018), and until now there has been limited evidence to suggest that any elasmobranchs have the ability to actively produce sound themselves. Here we present the first records of voluntary active sound production in the wild by three individuals of two species of stingray: the mangrove whipray Urogymnus granulatus (Figure 1b) and the cowtail stingray Pastinachus ater (Figure 1c). The sounds recorded from all three individuals were characterized by a series of very short, broadband clicks (Figure 1d, Appendix S1: Table S1) and were associated with movement of the spiracles and cranial area. In all recorded observations, the ray commenced producing sounds in response to an observer approaching closely and ceased sound production when the distance between the ray and observer increased. We suggest hypotheses for the potential purposes and mechanisms of the sound production and highlight that further research into this ability is needed. The three recorded observations occurred as follows. On 22 December 2018, Philip Christoff (PC) was undertaking a recreational closed-circuit rebreather dive at the Deep Turbo dive site northeast of Gili Trawangan, Gili Islands, Indonesia (Figure 1a, approximately −8.339491°, 116.048697°). At around 9:30 A.M., PC sighted an adult female mangrove whipray U. granulatus (disk width around 1 m) resting under the sand. Following a slow approach by PC, the ray appeared disturbed and slowly swam away parallel to the diver. It began making clicking sounds when PC came within ~2 m. Each click coincided with movement of the spiracle and partial retraction of the eye (Video S1). Eleven broadband clicks were recorded, ranging from 0.017 to 0.025 s in duration (mean ±SE = 0.021 ± 0.001) (Figure 1d-ii, Appendix S1: Table S1). Clicks 1–10 had a peak frequency of 1500 Hz, and the 11th click had a peak frequency of 1031 Hz (Appendix S1: Table S1). Mean bandwidth (±SE) across all clicks was 22.731 kHz ± 33.883 Hz (Appendix S1: Table S1). Secondary pulses were also noted in the waveforms of each click (Figure 1d-ii); however, based on their similarity to the primary pulses and lower relative amplitude, these were considered echoes within the camera housing (Nauticam housing on Sony RX100M5 digital camera). In February 2018, J. Javier Delgado Esteban (JJDE) observed sound production by a juvenile mangrove whipray U. granulatus (disk width around 40 cm) while snorkeling in the shallow, inshore waters of Geoffrey Bay, Magnetic Island, Great Barrier Reef, Queensland, Australia (Figure 1a, −19.153243°, 146.867342°). The juvenile was part of a larger group, but it had been separated from the group at the time it was recorded. Seven distinct broadband clicks were observed, ranging from 0.01 to 0.017 s in duration (mean ±SE = 0.013 ± 0.001) (Figure 1d-i, Appendix S1: Table S1). The first six clicks had a peak frequency of 1687 Hz, but the seventh click had a peak frequency of 1875 Hz (Appendix S1: Table S1). Mean bandwidth (±SE) across all clicks was 22.314 kHz ± 902.754 Hz (Appendix S1: Table S1). The clicks were described as originating from the ventral area of the animal, with each visibly coinciding with contractions of the spiracles (Video S1). Immediately after the sounds were emitted, the rest of the group of stingrays approached both the individual ray and the stationary snorkeler. JJDE observed numerous instances of sound production in this group of juvenile mangrove whiprays over several days, but these were not captured on film. The third observation was recorded in October 2017 by John Gaskell (JG) when snorkeling with a group of cowtail stingrays P. ater, which are known to aggregate in shallow waters off the southern beach of Heron Island (Figure 1a; −23.443510°, 151.913074°), Great Barrier Reef, Queensland, Australia. While filming in water approximately 70 cm deep, JG pursued one animal that was slowly swimming away from him. When JG came within a distance of less than a disk width of the ray, the animal started to produce loud clicking sounds that coincided with contractions of the cranial and spiracle area of the animal (Video S1). Five distinct broadband clicks were recorded, ranging from 0.021 to 0.091 s in duration (mean ±SE = 0.065 ± 0.012) (Figure 1d-iii, Appendix S1: Table S1). The first click had a peak frequency of 1406 Hz, while clicks 2–5 peaked at 1500 Hz (Appendix S1: Table S1). Mean bandwidth (±SE) across all clicks was 23.904 kHz ± 17.776 Hz (Appendix S1: Table S1). JG observed similar sound production two more times in the same species over 6 days, but these events were not captured on film. In addition to the foregoing observations recorded on film, in the early 2010s commercial divers from Far North Queensland were hand-collecting sea cucumbers in the inshore waters of the Great Barrier Reef and Coral Sea up to 20 m in depth and reported that on multiple occasions cowtail stingrays P. ater, when approached in murky waters, produced loud clicking sounds while fleeing from divers (B. E. Wueringer, unpublished). The observed sound production in both species of rays appeared to serve the purpose of agonistic displays. In sharks, agonistic displays are relatively common and mainly comprise visual components, such as lowering of the pectoral fins (silent) or tail slapping or popping, which does produce sounds (Martin, 2007), although these sounds are based on direct observations, and recording and analysis are still needed. In rays, agonistic displays observed to date generally have involved physical intra- and interspecific interactions, such as biting, chasing, and shoving (Newsome et al., 2004; Pini-Fitzsimmons et al., 2021). In contrast, the sudden loud sounds reported here appear to be more likely to represent a warning or serve to startle predators, such as sharks, which have been shown to rapidly flee from sudden unexpected sounds (Klimley & Myrberg, 1979; Myrberg, 2001). Further, since the rays are able to produce these sounds while fleeing from a fight-or-flight situation, they do not have to sacrifice their swimming efficiency in order to produce a warning signal (Martin, 2007). Both juvenile mangrove whiprays U. granulatus and cowtail stingrays P. ater appear social and are often observed feeding and resting in groups, likely as a predator-avoidance strategy (Kanno et al., 2019; Martins et al., 2020a, 2020b). In the case of JJDE's observation, other juvenile mangrove whiprays were observed gathering around the individual filmed producing the clicks and appeared to be doing so in response to the produced sounds. Sound production may therefore alert conspecifics to the need to aggregate in response to danger, which also implies a role in intraspecific communication. The bandwidth of the clicks produced by U. granulatus and P. ater examined here spanned the expected hearing range of elasmobranchs (40–1500 Hz; Chapuis & Collin, 2022), providing some evidence that their predators (Carcharhinus melanopterus and Negaprion acutidens; Kanno et al., 2019; Martins et al., 2020a, 2020b) and conspecifics can hear these sounds, although peak frequencies of the clicks occurred at the top or above this hearing range (1031–1875 Hz). However, audiograms have only been produced for a few elasmobranch species, and none has been produced for U. granulatus, P. ater, or their known predators (Chapuis & Collin, 2022). Further assessment of the hearing abilities of these species is therefore necessary to clarify the role of the produced sounds in agonistic displays or predator avoidance. The exact mechanism of sound production remains unclear but appears to be similar in both species. In all video recordings, contractions of the spiracles and associated gill openings are visible simultaneously with the clicking sounds (Video S1), indicating that sounds may be produced through fast contractions of the cranial and gill area. Because both species lack myliobatiform grinding plates, which would be positioned on the palate, but instead possess teeth limited to their jaws, the anecdotally proposed mechanism of sound production using grinding plates (Bass & Rice, 2010) is likely incorrect in this instance. Whether the sound production is achieved through fast expulsion of water or another internal mechanism is plausible but awaits verification, and further research on the internal morphology of these rays is required. The observations presented here highlight that further research on sound production in elasmobranchs is warranted, especially considering the limited number of examinations in this group to date (Looby et al., 2022). Our observations are of species that are encountered relatively often by snorkelers and yet were not previously known to produce sounds. Other similar species may also produce sounds, but anecdotal records may have not yet come to light; thus, our paper may serve to bring to light further examples from the public and researchers. All of the examples presented here were captured opportunistically with handheld digital cameras, and future targeted research should endeavor to use standardized hydrophones (Lindseth & Lobel, 2018; Rountree et al., 2006), where possible, to allow for better control of sound distortion and echoes. Our observations and Fish and Mowbray's (1970) observations in captivity mean that three ray species (of approximately 245 Myliobatiformes [Stein et al., 2018]) have now been convincingly shown to actively produce sounds and to do so in the wild, voluntarily, and without artificial stimuli. Although elasmobranchs are generally not considered to be sound producing (Looby et al., 2022), our study illustrates that this is a misconception and more research into their ability to produce and hear such sounds is required. Video contributions were made by J. Javier Delgado Esteban and John Gaskell. The original draft was written by Barbara E. Wueringer, Lachlan C. Fetterplace, and Joni Pini-Fitzsimmons, with further review and editing by Barbara E. Wueringer, Lachlan C. Fetterplace, Joni Pini-Fitzsimmons, and J. Javier Delgado Esteban. Analysis of footage was completed by Joni Pini-Fitzsimmons. Video S1 was created by John Gaskell. This paper is dedicated to Martin "Marty" Cunningham (North Cape Fisheries, Innisfail), who passed away in 2016. He first made Barbara E. Wueringer aware of sound production in rays in 2011. We are grateful to Philip Christoff for providing his observation for inclusion in this publication. Thanks to Clinton Duffy and Mark McGrouther and members of the Australasian Fishes project for helpful discussions of ray behavior. Veronika Biskis created the map. All presented observations were incidental, and therefore no animal ethics approval was sought beforehand. Authors declare that they have no competing interests. Videographic data (Fetterplace et al., 2022) is provided in Figshare at https://doi.org/10.6084/m9.figshare.16929838.v1. Appendix S1 Video S1 Video S1 Legend Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.

Sawfishes are among the most threatened families of marine fishes and are susceptible to incidental capture in net fisheries. Since bycatch reduction devices currently used in trawl fisheries are not effective at reducing sawfish catches, new methods to minimise sawfish bycatch are needed. Ideally, these should affect sawfish behaviour and prevent contact with the fishing gear. We tested the effects of electric fields on sawfish behaviour to assess the potential of electric pulses in mitigating sawfish bycatch. Experiments were conducted in a tank where 2 electrodes were suspended in the water column, connected to a pulse generator, and placed across the swimming path of sawfish. Two largetooth sawfish Pristis pristis were tested in control conditions, in the presence of a baseline pulse, and of 5 variations of that pulse where 1 parameter (polarity, voltage, frequency, pulse shape, pulse duration) was altered at a time. Conditional inference trees were used to identify the effects of various parameters (e.g. treatment, individual) on reaction type, reaction distance, twitching presence and duration, and inter-approach times. Sawfish reacted to electric fields, but reaction distances were small (typically <1.2 m), and no field tested consistently led to reactions conducive to escaping from moving nets. The following parameters induced the most response in both individuals: bipolar current, rectangular shaped, 5-10 Hz, ~1500 µs duration, and 100 V. We recommend further research focussing on moving nets, testing a V-shaped electric array preceding the net mouth by at least 5 m, and testing a setup similar to electrotrawling.

It has long been assumed that the elongated rostra (the saws) of sawsharks (family: Pristiophoridae) and sawfish (family: Pristidae) serve a similar function. Recent behavioural and anatomical studies have shed light on the dual function of the pristid rostrum in mechanosensory and electrosensory prey detection and prey manipulation. Here, the authors examine the distributions of the mechanosensory lateral line canals and electrosensory ampullae of Lorenzini in the southern sawshark, Pristiophorus nudipinnis and the longnose sawshark, Pristiophorus cirratus. In both species, the receptive fields of the mechano- and electrosensory systems extend the full length of the rostrum indicating that the sawshark rostrum serves a sensory function. Interestingly, despite recent findings suggesting they feed at different trophic levels, minimal interspecific variation between the two species was recorded. Nonetheless, compared to pristids, the pristiophorid rostrum possesses a reduced mechanosensory sampling field but higher electrosensory resolution, which suggests that pristiophorids may not use their rostrums to disable large prey like pristids do.

Populations of all species of sawfish have been depleted worldwide, and sawfish are now absent from much of their historic range. Much of the historic sawfish capture and encounter data does not provide information useful for species identification, and so cannot be used to reconstruct the historic ranges of the different species. For a long time, these data were also not easily accessible, as they were not digitised. Thus historic populations and distribution ranges of the different species could have been underestimated. Here, we examine historical newspaper articles (n=237) from the Australian National Library's online database ‘Trove', that were found by searching for the generic term ‘sawfish'. Articles were examined for information that could be relevant to sawfish biology and distribution, as outlined in the IUCN's Sawfish Conservation Strategy, such as date of capture, circumstance of capture, location, animals' weight and length, and potential species identifiers. One of the articles is presented in detail as it outlines a capture of Pristis pristis outside of the currently described range of this species, by over 800km. This evidence highlights the need for a global examination of historical print resources, which use generic terminology to report sawfish encounters. Examination of global news resources may help provide greater understanding of the full historic range of sawfishes, and allow a more accurate estimation of areas in which they no longer occur.

Populations of all species of sawfish have been depleted worldwide, and sawfish are now absent from much of their historic range. Much of the historic sawfish capture and encounter data does not provide information useful for species identification, and so cannot be used to reconstruct the historic ranges of the different species. For a long time, these data were also not easily accessible, as they were not digitised. Thus historic populations and distribution ranges of the different species could have been underestimated. Here, we examine historical newspaper articles (n=237) from the Australian National Library’s online database ‘Trove’, that were found by searching for the generic term ‘sawfish’. Articles were examined for information that could be relevant to sawfish biology and distribution, as outlined in the IUCN’s Sawfish Conservation Strategy, such as date of capture, circumstance of capture, location, animals’ weight and length, and potential species identifiers. One of the articles is presented in detail as it outlines a capture of Pristis pristis outside of the currently described range of this species, by over 800km. This evidence highlights the need for a global examination of historical print resources, which use generic terminology to report sawfish encounters. Examination of global news resources may help provide greater understanding of the full historic range of sawfishes, and allow a more accurate estimation of areas in which they no longer occur.

In 2011, a male pristiophorid was caught by a prawn trawler north east of Cape Moreton, Queensland, Australia. Molecular analyses confirmed the specimen to be the common sawshark Pristiophorus cirratus. Historical catch data indicate the occurrence of the species in the region but this is the first verified record of P. cirratus occurring in the waters of southern Queensland. Together, these records extend the recognised northern limit of P. cirratus by c. 500 km, which suggests that further investigation of its distribution is warranted.

Stomach contents were collected from 117 yellow rays Urobatis jamaicensis from three locations in south Eleuthera, The Bahamas and compared with ambient infauna via sediment surveys. Diets were relatively limited with a total of 535 prey items recovered, representing five taxonomic groups and dominated by polychaetes and decapod crustaceans (87% of total diet), while environmental sampling reported 5249 individual taxa represented by 62 taxonomic groups. Regardless of gravidity, sex or density of prey items among sites, no significant differences were detected. Foraging strategy plots suggested preferential prey is rare within the environment and the Manly-Chesson index validates polychaetes were consumed with high selectivity. This is the most comprehensive and updated assessment of comparative feeding in this species, particularly for The Bahamas, allowing insight into invertebrate community richness and diversity in ecologically sensitive coastal and nearshore habitats.

Detailed computational fluid dynamics simulations for the rostrum of three species of sawfish (Pristidae) revealed that negligible turbulent flow is generated from all rostra during lateral swipe prey manipulation and swimming. These results suggest that sawfishes are effective stealth hunters that may not be detected by their teleost prey's lateral line sensory system during pursuits. Moreover, during lateral swipes, the rostra were found to induce little velocity into the surrounding fluid. Consistent with previous data of sawfish feeding behaviour, these data indicate that the rostrum is therefore unlikely to be used to stir up the bottom to uncover benthic prey. Whilst swimming with the rostrum inclined at a small angle to the horizontal, the coefficient of drag of the rostrum is relatively low and the coefficient of lift is zero.

Potential roles of the rostrum of sawsharks (Pristiophoridae), including predation and self-defence, were assessed through a variety of inferential methods. Comparison of microwear on the surface of the rostral teeth of sawsharks and sawfishes (Pristidae) show that microwear patterns are alike and suggest that the elongate rostra in these two elasmobranch families are used for a similar purpose (predation). Raman spectroscopy indicates that the rostral teeth of both sawsharks and sawfishes are composed of hydroxyapatite, but differ in their collagen content. Sawfishes possess collagen throughout their rostral teeth whereas collagen is present only in the centre of the rostral teeth of sawsharks, which may relate to differences in ecological use. The ratio of rostrum length to total length in the common sawshark Pristiophorus cirratus was found to be similar to the largetooth sawfish Pristis pristis but not the knifetooth sawfish Anoxypristis cuspidata. Analysis of the stomach contents of P. cirratus indicates that the diet consists of demersal fishes and crustaceans, with shrimp from the family Pandalidae being the most important dietary component. No prey item showed evidence of wounds inflicted by the rostral teeth. In light of the similarities in microwear patterns, rostral tooth chemistry and diet with sawfishes, it is hypothesised that sawsharks use their rostrum in a similar manner for predation (sensing and capturing prey) and possibly for self-defence.

Within the Great Barrier Reef World Heritage Area in Queensland, Australia, lack of information on the distribution of sawfishes presents difficulty for informed management of their habitats and populations. This study aims to provide insights into the historical and current distributions through analysis of sawfish by-catch records from the Queensland Shark Control Program (QSCP), which has protected bathers since 1963 by targeting large sharks. Sawfishes have been caught in 8 of the 10 areas where the QSCP has been active. A total of 1450 captures of sawfishes (all 4 species known from Australia) were reported from 1963 to August 2016, with most (> 99%) in the 4 most northern areas; Cairns, Townsville, Mackay, and Rockhampton. Sawfishes were mainly captured in gillnets. Most (95.4%) animals were alive when the gear was checked. In Townsville and Rockhampton, standardised sawfish captures have declined over the years. No sawfish captures in QSCP gear have been recorded in 3 areas (Cairns, Townsville, Rockhampton) since gillnets were banned there, but in Mackay, where gillnets are still used, only 4 animals have been caught since 1999. It is recommended that QSCP contractors take more detailed data of future sawfish captures, and that contractors and fishers receive training on releasing sawfishes swiftly and with minimal damage. Moreover, as the use of gillnets in the QSCP has been decreasing over the years, fisheries-independent studies of current sawfish distributions are required.

The internal anatomy of the barbels of the common sawshark Pristiophorus cirratus was examined with light microscopy to clarify their sensory role. No sensory structures such as taste buds (chemoreception), ampullae of Lorenzini (electroreception) or free neuromasts (lateral line mechanoreception) could be located in the barbels. The presence of bundles of nerve fibres, however, indicates a tactile function for the barbels. Conveyance of information regarding potentially damaging stimuli (nociception) and temperature (thermoception) cannot be excluded at this stage. It is hypothesized that the barbels are used by P. cirratus to locate prey in both the water column and on the substratum via wake detection and sensing changes in surface texture. The barbels may also be involved in the detection of water currents for rheotaxis. Regression analyses on P. cirratus morphometric data showed that the width of the rostrum at two sections (the barbels and the rostrum tip) does not significantly correlate with total length. The regression analyses also suggested that the barbels of P. cirratus may be lateralised.

FisheriesVolume 41, Issue 2 p. 71-73 Essay What Is the Fate of Amputee Sawfish? David L. Morgan, David L. Morgan d.morgan@murdoch.edu.au Freshwater Fish Group and Fish Health Unit, Center for Fish and Fisheries Research, School of Veterinary and Life Sciences, Murdoch University, 90 South St., Perth, WA, AustraliaSearch for more papers by this authorBarbara E. Wueringer, Barbara E. Wueringer James Cook University, College of Marine and Environmental Sciences, Smithfield, QLD, Australia, Sharks and Rays Australia, Bungalow, QLD, AustraliaSearch for more papers by this authorMark G. Allen, Mark G. Allen Freshwater Fish Group and Fish Health Unit, Center for Fish and Fisheries Research, School of Veterinary and Life Sciences, Murdoch University, Perth, WA, AustraliaSearch for more papers by this authorBrendan C. Ebner, Brendan C. Ebner Freshwater Fish Group and Fish Health Unit, Center for Fish and Fisheries Research, School of Veterinary and Life Sciences, Murdoch University, Perth, WA, Australia, CSIRO Land and Water, and TropWATER, James Cook University, Atherton, QLD, AustraliaSearch for more papers by this authorJeff M. Whitty, Jeff M. Whitty Freshwater Fish Group and Fish Health Unit, Center for Fish and Fisheries Research, School of Veterinary and Life Sciences, Murdoch University, Perth, WA, AustraliaSearch for more papers by this authorAdrian C. Gleiss, Adrian C. Gleiss Freshwater Fish Group and Fish Health Unit, Center for Fish and Fisheries Research, School of Veterinary and Life Sciences, Murdoch University, Perth, WA, AustraliaSearch for more papers by this authorStephen J. Beatty, Stephen J. Beatty Freshwater Fish Group and Fish Health Unit, Center for Fish and Fisheries Research, School of Veterinary and Life Sciences, Murdoch University, Perth, WA, AustraliaSearch for more papers by this author David L. Morgan, David L. Morgan d.morgan@murdoch.edu.au Freshwater Fish Group and Fish Health Unit, Center for Fish and Fisheries Research, School of Veterinary and Life Sciences, Murdoch University, 90 South St., Perth, WA, AustraliaSearch for more papers by this authorBarbara E. Wueringer, Barbara E. Wueringer James Cook University, College of Marine and Environmental Sciences, Smithfield, QLD, Australia, Sharks and Rays Australia, Bungalow, QLD, AustraliaSearch for more papers by this authorMark G. Allen, Mark G. Allen Freshwater Fish Group and Fish Health Unit, Center for Fish and Fisheries Research, School of Veterinary and Life Sciences, Murdoch University, Perth, WA, AustraliaSearch for more papers by this authorBrendan C. Ebner, Brendan C. Ebner Freshwater Fish Group and Fish Health Unit, Center for Fish and Fisheries Research, School of Veterinary and Life Sciences, Murdoch University, Perth, WA, Australia, CSIRO Land and Water, and TropWATER, James Cook University, Atherton, QLD, AustraliaSearch for more papers by this authorJeff M. Whitty, Jeff M. Whitty Freshwater Fish Group and Fish Health Unit, Center for Fish and Fisheries Research, School of Veterinary and Life Sciences, Murdoch University, Perth, WA, AustraliaSearch for more papers by this authorAdrian C. Gleiss, Adrian C. Gleiss Freshwater Fish Group and Fish Health Unit, Center for Fish and Fisheries Research, School of Veterinary and Life Sciences, Murdoch University, Perth, WA, AustraliaSearch for more papers by this authorStephen J. Beatty, Stephen J. Beatty Freshwater Fish Group and Fish Health Unit, Center for Fish and Fisheries Research, School of Veterinary and Life Sciences, Murdoch University, Perth, WA, AustraliaSearch for more papers by this author First published: 28 January 2016 https://doi.org/10.1080/03632415.2015.1125887Citations: 6Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article.Citing Literature Volume41, Issue2February 2016Pages 71-73 RelatedInformation

Conservation geneticist Nicole Phillips and zoologist Barbara Wueringer reveal how vital northern Australia is to the future of sawfish.