Pristis Zijsron Research Articles

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

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 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.

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

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

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

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 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. 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, ~49% were sawfishes, while giant guitarfish and wedgefishes contributed to ~33% and 18% of records, respectively. 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). 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.

Evolution of the Critically Endangered Green Sawfish Pristis zijsron (Rhinopristiformes, Pristidae), Inferred from the Whole Mitochondrial Genome.

The green sawfish Pristis zijsron (Bleeker, 1851), a species of sawfish in the family Pristidae (Rhinopristiformes), mainly inhabits the Indo-West Pacific region. In this study, the complete mitochondrial genome of the critically endangered green sawfish is first described. The length of the genome is 16,804 bp, with a nucleotide composition of 32.0% A, 24.8% C, 13.1% G, and 30.0% T. It contains 37 genes in the typical gene order of fish. Two start (GTG and ATG) and two stop (TAG and TAA/T-) codons are found in the thirteen protein-coding genes. The 22 tRNA genes range from 67 bp (tRNA-Ser) to 75 bp (tRNA-Leu). The ratio of nonsynonymous substitution (Ka) and synonymous substitution (Ks) indicates that the family Pristidae are suffering a purifying selection. The reconstruction of Bayesian inference and the maximum likelihood phylogenetic tree show the same topological structure, and the family Pristidae is a monophyletic group with strong posterior probability. Pristis zijsron and P. pectinata form a sister group in the terminal clade. And the divergence time of Rhinopristiformes show that P. zijsron and P. pectinata diverged as two separate species in about Paleogene 31.53 Mya. Complete mitochondrial genomes of all five sawfishes have been published and phylogenetic relationships have been analyzed. The results of our study will provide base molecular information for subsequent research (e.g., distribution, conservation, phylogenetics, etc.) on this endangered group.

Growth and morphology of Critically Endangered green sawfish Pristis zijsron in globally important nursery habitats

Understanding growth rates and other basic life-history information of imperilled species is essential to assessing the extent of threats to a population, but often difficult due to limited access to study subjects. Here we used mark-recapture data to estimate growth rates of juvenile Critically Endangered green sawfish (Pristis zijsron) in a globally important nursery in the eastern Indian Ocean (Western Australia). Our results suggest that growth of juvenile sawfish in this part of the central Western Australian coast is significantly slower compared to populations on the north-eastern coast of Australia. Additionally, growth rates differed between nearby areas within the nursery region, potentially due to differential productivity or anthropogenic effects. Morphological relationships between total length, rostral length, mouth gape, and clasper length are presented, which will allow for greater accuracy in estimating biological parameters in this species, while updated information on size at maturity (> 3200 mm) and size at birth (approximately 750–900 mm) will help to clarify life-history parameters for this data-poor species. Furthermore, there were distinct differences in the number of rostral teeth of green sawfish between this eastern Indian Ocean population and other populations throughout their current distribution, indicating substantial genetic differentiation in this species globally. These results will help to accurately assess growth trajectories and potential impacts of fisheries and other threats to green sawfish. Additionally, results highlight the importance of assessing population-specific growth rates in threatened species and of considering potential long-term life-history impacts of anthropogenic developments and activities.

Novelty and phylogenetic affinities of a new family of tapeworms (Cestoda: Rhinebothriidea) from endangered sawfish and guitarfish

The parasites of hosts of conservation concern are often poorly known. This is the case with the iconic group of elasmobranchs known as the sawfish of the genus Pristis, all four species of which are considered as Endangered or Critically Endangered by the International Union for Conservation of Nature (IUCN, Switzerland). Examination of cestodes from three species of sawfish (Pristis pristis, Pristis clavata, and Pristis zijsron) in Australia and one of their close relatives, the also critically endangered widenose guitarfish, Glaucostegus obtusus, in India, collected over the past 25 years, yielded four new species of tapeworms which are described herein. All four belong to the previously monotypic Mixobothrium; the diagnosis of the genus is revised to accommodate the new species. Among the new taxa is a species that had been included in previous molecular phylogenies but whose identity and affinities within the order Rhinebothriidea, and thus also its familial placement, were unclear. This species exhibits the morphological features of Mixobothrium and thus its identity is, at long last, revealed. Sequence data generated for the 28S rDNA gene for three of the new species, as well as an additional new but yet undescribed species from Pristis pectinata from Florida (USA), confirms the uniqueness of this group among the rhinebothriideans. The new family Mixobothriidae is established to house these taxa. The members of this family differ from all but one of the five other families of rhinebothriideans in lacking apical suckers on their bothridia. They are also distinctive in that their bothridia are divided into three regions. The anterior and posterior regions have similar locular configurations to one another and differ from the locular configuration of the middle region. As a consequence, the bothridia are symmetrical along both their vertical and horizontal axes. We predict that a focus on species of guitarfish in the genus Glaucostegus will be the most productive approach for discovering additional diversity in this family of cestodes.

A new microbothriid monogenean Dermopristis pterophilus n. sp. from the skin of the Critically Endangered green sawfish Pristis zijsron Bleeker, 1851 (Batoidea: Pristidae) in Western Australia.

A new microbothriid monogenean Dermopristis pterophilus n. sp. is described from the skin of the Critically Endangered green sawfish Pristis zijsron Bleeker, 1851 in the Ashburton River delta, northern Western Australia. Analyses of the 28S ribosomal DNA marker and the molecular barcoding markers Histone 3 and Elongation Factor 1 α confirmed position among the Microbothriidae, with close affinity to the only other sequenced representative of Dermopristis Kearn, Whittington and Evans-Groing, 2010. The new species is morphologically consistent with the concept of Dermopristis; it has two testes, lacks a male copulatory organ and has a simple haptor. It is smaller than its two congeners D. paradoxus Kearn, Whittington and Evans-Gowing, 2010 and D. cairae Whittington and Kearn, 2011 and is most similar to the former, distinguished only in that it lacks the strong, transverse, parallel ridges on the ventral body surface that characterise that species. It is more easily distinguished from D. cairae, differing in body shape, possession of a seminal receptacle, and relative position and size of the haptor. It may further differ from both species by fine details of the gut diverticula, although these details are difficult to ascertain. Spermatophores were observed in the new species, similar to those previously reported for D. cairae. The new species exhibits site attachment preference: infections were greatest on and immediately adjacent to the host pelvic fins (including male reproductive organs, i.e. claspers), moderate in proximity to the dorsal and pectoral fins, few on the caudal fin and peduncle, and infrequently, isolated worms occurred elsewhere on the dorsal and ventral surfaces of the body. There was no incidence of infection on the head (including rostrum). We presume D. pterophilus is restricted to P. zijsron and thus likely faces the same threat of extinction.

Impacts of trophy collection and commercial fisheries on sawfishes in Queensland, Australia

Globally, populations of sawfishes (Batoidea: Pristidae) have declined due to directed fishing and bycatch. Before international trade protection, sawfish rostra were often collected as trophies, and sawfish fins could fetch some of the highest prices in the shark fin trade. Australia is now considered a global stronghold for 4 out of 5 species. The present study analyses data of 723 sawfish rostra from all 4 Australian species that were caught in Queensland over the last 100 years. The majority of rostra (92.2%) originated from gillnet captures. Morphometric data from rostra were used to calculate sawfish total lengths and ages at mortality using published ratios. Rostra were split into the mass retention subgroup (n = 569), which originated from ≤5 active commercial inshore gillnet fishers with known large geographic origin regions and decades of origin, and the small-scale retention subgroup (n = 154), for which individual years and locations are known. Across all regions of Queensland, species composition changed significantly before and after the year 2000. After 2000, Anoxypristis cuspidata became the dominant species on the east coast. Large adult Pristis zijsron were present across Queensland before 2000 and numbers declined after this. The commercial gillnet industry likely impacts all life history stages of sawfishes. Since 2002, it has become compulsory for Queensland’s commercial fishers to report interactions with sawfishes in SOCI (Species of Conservation Interest) logbooks. Comparison of rostra from gillnet captures with logbook data indicates that underreporting is higher than previously assumed.

New genera, species and records of rhinebothriidean cestodes (Platyhelminthes) parasitic in Australian stingrays (Elasmobranchii: Batoidea).

Collections of rhinebothriidean cestodes (Platyhelminthes) from Australian batoid elasmobranchs revealed the presence of a number of new genera and species. Ruptobothrium louiseuzeti n. g., n sp. is described from the reticulate whipray, Himantura australis Last, Naylor & Manjaji-Matsumoto, from off the Northern Territory and Mixobothrium queenslandense n. g., n sp. is described from the green sawfish, Pristis zijsron Bleeker, from off north-eastern Queensland. Two new species of Rhabdotobothrium Euzet, 1953 are described: Rhabdotobothrium meridionale n. sp. from the southern eagle ray Myliobatis tenuicaudatus Hector from off South Australia and Rhabdotobothrium anoxypristidis n. sp. from the narrow sawfish, Anoxypristis cuspidatus (Latham) from off north Western Australia. A new species of Scalithrium Healy & Reyda, 2016, Scalithrium australiense n. sp., is described from the reticulate whipray, Himantura australis Last, Naylor & Manjaji-Matsumoto, from off northern Western Australia. Scalithrium smitii (Shinde, Deshmukh & Jadhav, 1981) n. comb. is reported from Australian waters for the first time in the black spotted stingray Maculabatis toshi (Whitley) from off northern Western Australia. New host and geographical records are provided for Stillabothrium jeanfortiae Forti, Aprill & Reyda, 2016 from the brown whipray Maculobatis toshi (Whitley) and the black-spotted whipray, Maculabatis cf. astra (Last, Manjaji-Matsumoto & Pogonoski) from Moreton Bay in southern Queensland.

Quantifying vulnerability of sharks and rays species in Indonesia: Is biological knowledge sufficient enough for the assessment?

Sharks and rays are vulnerable species, which are highly exploited in Indonesian waters but lacked of detailed information on their ecology and fisheries status. This research aims to assess the level of vulnerability of sharks and rays to overfishing using the maximum intrinsic rate of population increase (rmax), derived from the Euler-Lotka equation, as a proxy of extinction risk. It is calculated based on several biological parameters including fecundity, maximum age, age at maturity, and the number of offspring. Using rmax calculation adapted to shark and ray life history traits by accounting for survival to maturity, we were able to calculate rmax values for 26 out of 208 sharks and rays species present in Indonesia. This includes vulnerable species such as Mobula alfredi, Prionace glauca, and Pristis zijsron. This result showed that rmax is a valuable tool which can be used to quantify extinction risk with some level of precision, but it also highlights the necessity to collect important biological information of the most vulnerable species to further estimate their status. This approach requires complementary information related to external threats such as habitat degradation, species economic value and threat level from local fishing effort and related fishing gears.

First confirmed record of the Critically Endangered green sawfish Pristis zijsron from Bangladeshi waters.

In a study identifying the species composition of illegally traded elasmobranch products, evidence was collected of the presence of green sawfish Pristis zijsron in Bangladeshi waters of the Bay of Bengal. This is the first confirmed record of Pristis zijsron from this region, extending its known range > 1000 km to the north-west. This is an important record in a region where sawfish have declined significantly and are now rarely sighted; it highlights the urgency of further regional species-specific studies within the Indian Ocean.

Habitat use and site fidelity of neonate and juvenile green sawfish Pristis zijsron in a nursery area in Western Australia

The largest of the sawfishes is the Critically Endangered green sawfish Pristis zijsron, a species believed to have undergone a major decline (38%) in extent of occurrence. Conservation efforts are hampered by the lack of information on the habitat requirements of this species. We used passive acoustic telemetry to document the movement patterns of 37 juvenile P. zijsron (<3000 mm total length) in a recently discovered nursery area in a remote estuary and adjacent mangrove creeks in the Pilbara region of Western Australia. All age classes had a high site fidelity near the mouth of the Ashburton River (<700 m upstream) or in the adjacent tidal mangrove creeks. Neonates stayed close to the river mouth for several months, with movement in creasing with growth. For larger individuals, movement between the river mouth or creeks and nearshore coastal habitats was largely tidally driven, with nearshore coastal habitats used during low tide and protected tidal waters (mangrove creeks) used during high tide. Emigration from the river estuary appeared to be influenced by increases in freshwater discharge and high turbidity brought on by cyclonic rainfall events. The high relative abundance and site fidelity of multiple age classes of P. zijsron over multiple years confirms that the study area provides important nursery habitats for the species. Additionally, the localised movements of juveniles suggest that this population may be sensitive to disturbances within these habitats. Given the significance of this region for P. zijsron, it is imperative to focus conservation efforts here to ensure that the population remains in a relatively healthy condition.

Genetic bottlenecks in Pristis sawfishes in northern Australian waters

Northern Australia has been identified as the last stronghold for the dwarf sawfish Pristis clavata, green sawfish P. zijsron, and largetooth sawfish P. pristis, making these populations key in global conservation efforts for each species. This research assesses the levels of genetic diversity in these 3 sawfishes in Australian waters, testing for the presence of population bottlenecks using data at microsatellite loci. Levels of observed heterozygosity in each species from the west coast of Australia and the north-eastern Gulf of Carpentaria were generally high. M ratio tests suggest that assemblages of P. zijsron and P. pristis on the west coast and P. clavata and P. zijsron in the Gulf of Carpentaria may have experienced population bottlenecks. The bottlenecks are especially pronounced in P. zijsron populations and in P. clavata from the Gulf of Carpentaria. Demographic analyses, based on mtDNA data, indicate relatively recent (evolutionarily) range expansions in Pristis sawfishes in northern Australian waters, which could account for the population bottlenecks. A more recent range expansion in each of P. clavata and P. zijsron, as evidenced by more recent population divergence and more recent/higher rates of historic maternal gene flow, could account for the more pronounced bottlenecks in these species when compared to P. pristis. Given that Pristis sawfishes in Australian waters have experienced population bottlenecks, whether they be historic, contemporary or both, the preservation of remaining genetic diversity should be a high conservation priority.

Is this the last stand of the Critically Endangered green sawfish Pristis zijsron in the Arabian Gulf?

Is this the last stand of the Critically Endangered green sawfish Pristis zijsron in the Arabian Gulf?

Are sawfishes still present in Mozambique? A baseline ecological study.

Sawfishes (Pristidae) were formerly abundant in the western Indian Ocean, but current data on sawfish presence and distribution are lacking for most of the region. This paper summarises historical records of sawfishes in Mozambican waters and presents the findings of the first assessment of the presence and status of sawfishes in Mozambique. A countrywide baseline assessment was undertaken between May and July 2014, using interviews with artisanal, semi-industrial and industrial fishers, fish traders and fisheries monitoring staff as the primary source of information on sawfish distribution, recent catches, socio-economic value and cultural importance. Additional interviews were conducted via email or telephone with individuals running sport fishing operations or who otherwise had considerable experience interacting with the fishing sectors or the marine environment in Mozambique. Where encountered, sawfish rostra were photographed and a series of measurements and associated data were collected. In total, 200 questionnaire surveys and seven interviews with recreational fishing and dive operators were conducted, and 19 rostra were documented from museum archives and private collections, belonging to two sawfish species, the Largetooth Sawfish (Pristis pristis) and Green Sawfish (P. zijsron). The most recent captures of sawfishes were reported to have occurred in 2014. Two key sites were identified where both recent encounters were reported and numerous Largetooth Sawfish rostra were documented. Gill nets were the fishing gear most commonly attributed to sawfish catches. Sawfishes did not hold any cultural importance in Mozambique, but they have at least some socio-economic importance to artisanal fishers, primarily through the sale of their fins. The meat did not appear to be held in high regard and was usually consumed locally. Sampling and further research is now required to confirm the presence of sawfishes and to assess the primary threats to sawfishes in those areas. At one site where a number of rostra were present and where fishers stated that they still catch sawfish, gill nets are being provided to fishers as an alternative to beach seining. This may have a serious impact on the local sawfish population and more broadly for other elasmobranchs in the area. Immediate action is required to develop a landings monitoring programme in this and other key habitats, and to encourage fishers to release sawfishes alive.

Occurrence of the green sawfish Pristis zijsron in the Sudanese Red Sea with observations on reproduction

Occurrence of the green sawfish Pristis zijsron in the Sudanese Red Sea with observations on reproduction

Discovery of a pupping site and nursery for critically endangered green sawfish Pristis zijsron.

A pilot study targeting sawfishes in the southern Pilbara region of Western Australia, which is undergoing a major expansion in human activity, was conducted using gillnets during April and October 2011 in the Ashburton Estuary and adjacent mangrove creeks. Catch per unit effort was greatest in the Ashburton Estuary in October, due to an influx of green sawfish Pristis zijsron pups, and was orders of magnitude higher than previously reported for any Pristidae; the study sites contained P. zijsron up to almost 3 m total length. This study identified the first pupping site for P. zijsron in Western Australia, and the most southerly known nursery area for the species in Australian waters, and is potentially the most important globally.

Do sawfish Pristis spp. represent South Africa's first local extirpation of marine elasmobranchs in the modern era?

Largetooth sawfish Pristis pristis and green sawfish P. zijsron were not uncommon in catches made in KwaZulu‑ Natal (KZN) on the east coast of South Africa in the mid part of the last century but apparently have disappeared from this area. This paper traces the decline in sawfish catches from 1951 and assesses the current population status and local extinction risk, based on historical and current records up to 2012. Records were collected from research surveys, literature, media and museum specimens, and through contacting researchers and conservation managers who have worked in KZN coastal and estuarine areas. A total of 150 green sawfish, 7 largetooth sawfish and 89 unidentified sawfish records were located. Most sawfish (115) were caught during a four‑year (1967–1970) gillnetting survey conducted by the Oceanographic Research Institute in the St Lucia estuarine system while 91 were caught in the bather protection nets installed and maintained along the KZN coast by the KwaZulu‑Natal Sharks Board. Sawfish ranged from 63 to 533 cm total length (TL). Sawfish caught in the estuarine environments (mean TL 162 cm [SD 72], n = 95) were significantly smaller than those caught in the inshore marine environments (mean TL 310 cm [SD 109], n = 83), confirming the importance of estuaries as pupping and nursery areas. The St Lucia estuarine system, given the high abundance of sawfish, was determined to be the most important nursery area in KZN. The last sawfish encountered in KZN, which was not identified to species level, was caught in the bather protection nets in 1999 and released alive. Extinction probability analysis indicates that sawfish no longer occur in KZN waters. Anthropogenic changes to the St Lucia estuarine system, as well as to other KZN estuaries, gillnetting for bather protection, and illegal fish harvesting, coupled with a non‑adaptive life‑history style, may have precipitated the disappearance of sawfish from KZN waters.

Ghosts of the coast: global extinction risk and conservation of sawfishes

Abstract Sawfish are arguably the world's most imperilled marine fishes. All five species are classified as highly threatened with extinction: three are Critically Endangered (smalltooth sawfish Pristis pectinata, largetooth sawfish Pristis pristis, and green sawfish Pristis zijsron); two are Endangered (narrow sawfish Anoxypristis cuspidata, and dwarf sawfish Pristis clavata). Sawfishes are threatened primarily due to a combination of their low intrinsic rates of population increase, high catchability in fisheries, and high value. Sawfishes are among the world's largest marine fishes, and they are caught by a wide range of fishing gears owing to their tooth‐studded rostra being easily entangled. Sawfish fins are some of the most valuable for shark fin soup, and their rostra have long been traded as curios. In addition, they inhabit shallow coastal waters, estuaries, and rivers of the tropics and subtropics, down to a maximum depth rarely exceeding 100 m and are associated with threatened mangrove and seagrass habitats. Historically, sawfishes were distributed in the coastal waters of 90 countries and territories. Over the past century, their geographic distribution has been greatly diminished. For example, the smalltooth sawfish is now found in &lt;20% of its former range. Globally, sawfishes are now entirely absent from 20 countries; 43 countries have lost at least one species. Sawfishes are legally protected, to some degree, in 16 of the 90 range states. These safeguards encompass, on average, 81% of their Extant distribution; however, the quality and breadth of protection varies dramatically across countries and species. Smalltooth sawfish currently has the least amount of such coverage of only half (49%) of Extant distribution. The global conservation strategy specifies actions to protect sawfish and their habitats. Such actions are urgently warranted to avoid global extinction and to restore robust populations for the benefit of coastal ecosystem function and biodiversity. © 2014 The Authors. Aquatic Conservation: Marine and Freshwater Ecosystems published by John Wiley &amp; Sons, Ltd.

A review of sawfishes (Pristidae) in the Arabian region: diversity, distribution, and functional extinction of large and historically abundant marine vertebrates

Abstract Sawfishes (Pristidae) are large shark‐like batoids (rays) that are among the most threatened of all marine fishes. While there is a broad consensus of severe sawfish declines globally, detailed status assessments for most of their vast circumtropical distribution do not exist. This paper reviews sawfishes of waters adjacent to the Arabian Peninsula, focusing on the Gulf. Until around the 1960s, sawfishes were abundant and widespread in the region, but since around the 1980s, they have been rarely recorded. Sawfishes can now be considered extinct as a functional component of coastal ecosystems, and may be close to being regionally extinct. This assessment is based on the overwhelming weight of evidence from diverse sources such as archaeological data, historical accounts, grey literature, personal communications and extensive fish surveys. Based on 176 individual records, Pristis zijsron was the most frequently recorded species, occurring in all regional seas. Anoxypristis cuspidata records were limited to the coasts of Iran, Pakistan, and Masirah Island (Oman). The first substantiated Pristis pristis records from the Arabian Peninsula are provided, and two records not identifiable to species do not exclude the possibility that Pristis clavata occurs in the region. Humans have used sawfishes as a food, oil, trade, and cultural resource for several thousands of years. Fins have been highly valued since at least the mid‐19th century. Based on recent and historical records, known biology, and marine conservation programmes for other species or habitats, priority areas for sawfish research and recovery programmes are the central southern Gulf; significant mangrove areas in Iran and the UAE; the Musandam Peninsula; and Masirah Island (Oman). Historical regional declines coincide with the widespread availability of nylon gillnets, to which sawfishes are disproportionately vulnerable. Any attempt at sawfish recovery must enforce strict controls on gillnetting, which could have significant benefits for other marine species of commercial and conservation interest. Copyright © 2014 John Wiley &amp; Sons, Ltd.