Collaborative methods identify a remote global diversity hotspot of threatened, large‐bodied rhino rays

Aquatic Conservation Marine and Freshwater Ecosystems, Journal Year: 2024, Volume and Issue: 34(1)

Published: Jan. 1, 2024

Abstract 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 rays the order Rhinopristiformes from Pilbara region Western Australia, with focus on Ningaloo Coast World Heritage Area and adjacent Exmouth Gulf. Occurrence data were compiled various sources including commercial fishing reports (35%), citizen science (34%), targeted scientific surveys (30%) published literature (1%). The was inhabited by all Australia's Pristidae (four sawfish species), Rhinidae (three wedgefish species) sole Australian representative Glaucostegidae (giant shovelnose ray). Of records, ~49% sawfishes, while giant guitarfish wedgefishes contributed ~33% 18% respectively. Gulf appears be important pupping area for green ( Pristis zijsron ) which most commonly encountered pristid. Bottlenose Rhynchobatus australiae rhinid, less frequent encounters shark Rhina ancylostoma eyebrow palpebratus ). host life stages ray Glaucostegus typus combined use highlighted as ‘lifeboat’ these These are essential in creating effective conservation management plans this refuge, relevant global initiatives.

Language: Английский

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The red fox (Vulpes vulpes) as a potential invasive predator in a Critically Endangered sawfish nursery

Pacific Conservation Biology, Journal Year: 2025, Volume and Issue: 31(1)

Published: Jan. 1, 2025

Although the red fox (Vulpes vulpes) is considered one of most damaging and adaptive invasive carnivorous mammals that consumes a wide variety vertebrate invertebrate taxa, there are surprisingly few reports foxes hunting fish. We observed evidence an attempted predation event by on neonate green sawfish (Pristis zijsron) within deltaic island in Ashburton River estuary, remote desert river Western Australia. The site globally important nursery where newborn arrive annually spring. Injuries to included paw/claw marks head, damage rostrum, which formidable tool used for both defence against predators detecting attacking prey, as well major hole head gills, vital respiration, osmoregulation, nitrogenous waste excretion, pH regulation, hormone production. A series tracks suggests at least parades shallow tidally influenced banks, with mud crab (Scylla serrata) having also been predated on. There have sea turtle nests nearby. This first record marine waters identifying fish prey. suggest monitoring program foxes, possibly control program, warranted prior annual seasonal colonisation this habitat nesting turtles, may turn reduce sympatric species.

Language: Английский

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Fine‐tuning established morphometric models through citizen science data

Conservation Science and Practice, Journal Year: 2025, Volume and Issue: unknown

Published: Feb. 26, 2025

Abstract 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 photographs to fill gaps distribution population estimates. However, established morphometric models that allow estimation total length from are restricted by available generate them, with many constructed solely juvenile data, robust error testing rarely performed. This study generates an independent dataset citizen science field measurements, incorporating sawfishes all life history stages, test robustness previously proposed for four Indo‐Pacific sawfish species. Rostrum‐to‐length (RLMs) were confirmed Pristis clavata pristis , a new model was zijsron . A key source RLMs Anoxypristis cuspidata identified as changing rostrum morphology body size, but there insufficient measurements present propose this highlights problems associated extrapolating lengths animals beyond size bounds used produce original model. historically exploited species like which often represented collections trophies alone, these methods outline critical step prior use further ecological study.

Language: Английский

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Effects of coastal development on sawfish movements and the need for marine animal crossing solutions

Conservation Biology, Journal Year: 2024, Volume and Issue: 38(4)

Published: April 5, 2024

Abstract Although human‐made barriers to animal movement are ubiquitous across many types of ecosystems, the science behind these and how ameliorate their effects lags far in marine environments compared with terrestrial freshwater realms. Using juvenile sawfish an Australian nursery habitat as a model system, we aimed assess major anthropogenic development on behavior coastal species. We catch rates (via acoustic telemetry) green ( Pristis zijsron ) before after structure was built important habitat. Acoustic tracking data showed that did not affect levels recruitment nursery, but it constrain movements juveniles moving throughout demonstrating reluctance shoreline‐associated species travel around large or unfamiliar structures. Given current lack information environment, findings highlight need for further research this area, propose experimentation crossings area emerging research.

Language: Английский

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Ectoparasites of the Critically Endangered green sawfish Pristis zijsron and sympatric elasmobranchs in Western Australia

Parasitology International, Journal Year: 2024, Volume and Issue: 101, P. 102900 - 102900

Published: May 1, 2024

This study reports the metazoan ectoparasite fauna of juvenile Critically Endangered green sawfish, Pristis zijsron, and sympatric elasmobranchs in Western Australia. Five parasite taxa were found on 76 screened P. zijsron: Caligus furcisetifer (Copepoda: Caligidae), Dermopristis pterophila (Monogenea: Microbothriidae), Branchellion plicobranchus Stibarobdella macrothela (Hirudinea: Piscicolidae), praniza larvae an unidentified gnathiid isopod. Only C. D. common, exhibiting discrepant site-specificity, with occurring mostly head rostrum, around pectoral pelvic fins. Intensity infection for increased host total length was influenced by sex, but opposite directions; intensity greater female whereas males. In Ashburton River, likelihood zijsron time since substantial freshwater discharge events, suggesting decreased salinity impacts both taxa. addition to five other elasmobranch species opportunistically ectoparasites area: giant shovelnose ray, Glaucostegus typus, eyebrow wedgefish, Rhynchobatus palpebratus, nervous shark, Carcharhinus cautus, lemon Negaprion acutidens, graceful amblyrhynchoides. R. palpebratus; no parasites species. Conversely, Perissopus dentatus Pandaridae) all three carcharhinids not batoid rays (P. G. typus or palpebratus).

Language: Английский

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Kinship assessment and insights into reproductive behaviour of the Critically Endangered green sawfish Pristis zijsron in Western Australia

Aquatic Conservation Marine and Freshwater Ecosystems, Journal Year: 2024, Volume and Issue: 34(6)

Published: June 1, 2024

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

Language: Английский

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A review of the life history and ecology of euryhaline and estuarine sharks and rays

Reviews in Fish Biology and Fisheries, Journal Year: 2023, Volume and Issue: 34(1), P. 65 - 89

Published: Oct. 23, 2023

Abstract One-third of all elasmobranchs (sharks and rays) are threatened with extinction. Euryhaline estuarine generalist a group 29 species that occupy non-marine environments during particular life-stages. These poorly known disproportionately threatened, 72.4% at risk extinction or Data Deficient. A detailed knowledge species’ life history characteristics, movement ecology, habitat use, population structure required for the implementation appropriate management conservation measures. To date, research on euryhaline has lagged behind marine species. Here, literature review gap analysis was conducted to identify gaps in 14 key parameters management. Of species, only Bull Shark ( Carcharhinus leucas ) Largetooth Sawfish Pristis pristis had information majority assessed. Nine lack most parameters, while Broadnose Wedgefish Rhynchobatus springeri lacks but one investigated. There is high level understanding age- size-at-maturity, size-at-birth, growth five nine have estimates natural mortality. Comprehensive reproductive biology data unavailable six Both short- long-term ecology well-understood two use Population been studied eight structure, requirements urgently develop strategies secure populations.

Language: Английский

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Trends in catch rates of sawfish on the Australian North West Shelf

Endangered Species Research, Journal Year: 2023, Volume and Issue: 53, P. 23 - 33

Published: Nov. 17, 2023

Northwestern Australia is thought to have some of the world’s last remaining viable sawfish populations, although little quantitative data exists on their status or trends. This study examined 17 years logbook bycatch records (n = 815) for green Pristis zijsron and narrow Anoxypristis cuspidata from a trawl fishery operating Australian North West Shelf. Incidental captures by are rare, occurring approximately once every 75 trawls (~199 hours). To standardize catch rates account excess zeros in data, we employed generalized additive models location, scale, shape (GAMLSSs) using zero-inflated Poisson distribution. For sawfish, doubled over period, while an oscillating trend was observed rates. Reported occurred throughout management boundaries fishery, which operates mid-shelf waters 48 121 m. A weak seasonal signal detected both species, with highest capture numbers during autumn-winter, consistent expected inshore migration parturition spring-summer. Logbook trends were partly corroborated independently verified collected subset years, also showed increasing proportion catch. Our findings emphasize importance populations northwestern within context global conservation efforts this taxon.

Language: Английский

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Life‐history of the spiny butterfly ray, Gymnura altavela (Chondrichthyes: Myliobatiformes), kept under human care in a marine aquarium

Journal of Fish Biology, Journal Year: 2024, Volume and Issue: 105(4), P. 1060 - 1073

Published: July 10, 2024

The Rio de Janeiro Marine Aquarium (AquaRio) is the first to successfully maintain and reproduce spiny butterfly ray (Gymnura altavela), providing unique information about species' biology. Seven rays were kept in captivity between 2018 2023, two captured on southeastern coast of Brazil five born aquarium. applied abiotic conditions nutrition allowed for survival, growth, reproduction these individuals. Growth parameters (asymptotic disk width-DW

Language: Английский

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Evidence of long-distance movement of green sawfish (Pristis zijsron) in Western Australia

Marine and Freshwater Research, Journal Year: 2024, Volume and Issue: 75(17)

Published: Nov. 21, 2024

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

Language: Английский

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