William Toby WhiteCSIRO Oceans & Atmosphere Flagship · Australian National Fish Collection
Skills and Expertise
Jan 1998 - Nov 2006
- School of Veterinary and Life Sciences
- Perth, Australia
Research Items (241)
The elasmobranch bycatch of the Gulf of Papua Prawn Fishery is investigated in detail for the first time. Fisheries observers collected data on the elasmobranch bycatch from a total of 403 trawl sets (1,273 hrs) in the Gulf of Papua. A total of 40 species of elasmobranchs were recorded ranging in size from a 12 cm disc width stingray to a 350 cm total length sawfish. High mortality rates were recorded (>80%), attributed to the long trawl durations (up to 4 hours). The future inclusion of bycatch reduction devices would likely reduce the number of larger elasmobranchs being caught, based on evidence from the prawn trawl fisheries of northern Australia, and is being investigated by the PNG National Fisheries Authority. Differences in catch compositions were detected across the management zones as well as between the two monsoonal seasons (SE Monsoon and NW Monsoon). Increased monitoring and additional research is required and management plans should address the elasmobranch bycatch and in particular their high mortality rate.
- Apr 2019
A checklist of the marine and estuarine fishes of New Ireland Province is presented, with special emphasis on Kavieng District, combining both previous and new records. After the recent KAVIENG 2014 expedition, a total of 1325 species in 153 families were recorded from the region. The largest families are the Gobiidae, Pomacentridae, Labridae, Serranidae, Apogonidae, Lutjanidae, Chaetodontidae, Blenniidae, Carangidae, Acanthuridae, Scaridae, Holocentridae, Syn-gnathidae, Lethrinidae and Scorpaenidae. A total of 810 fish species (61.1 % of the total marine and estuarine fish fauna) are recorded from New Ireland for the first time. The fish fauna of New Ireland includes 142 species in transitional waters and 1264 species in marine habitats, and 54 species species in freshwater habitats. Zoogeographically, 1179 species have a wide distribution range, most frequently a broad Indo-West Pacific distribution. Among the remaining species, just 12 are endemic to New Ireland.
Shark−like batoids (Order Rhinopristiformes) are normally taken as incidental catch in fisheries targeting other species, one exception is a poorly understood Indonesian tangle net fishery. Market surveys of Muara Angke landing port recorded landed catch for this fishery. Recent catch data from Indonesian Capture Fisheries (2017 − 2018) were also examined to provide contemporary information. During the market surveys, 1,559 elasmobranchs were recorded, comprised of 24 species of batoids and nine species of sharks. The most abundant were pink whipray Pateobatis fai and bottlenose wedgefish Rhynchobatus australiae , the latter being the main target species. Catch composition differed between individual tangle net boat landings, likely reflecting different fishing grounds, seasonal variation and potential localised declines in species over time. The fishery is highly selective for larger size classes, but smaller size classes of target species are also caught in high numbers in other Indonesian fisheries such as trawl, small mesh gillnet, and hand− and long− line fisheries. As of July 2018, the tangle net fishery was still operating, but few wedgefish were caught and the main landed catch was stingrays. Evidence of substantial and rapid declines in landings of wedgefish species, raises concerns about the status of shark−like batoids and stingrays in Indonesia.
Carcharhinus obsolerus is described based on three specimens from Borneo, Thailand and Vietnam in the Western Central Pacific. It belongs to the porosus subgroup which is characterised by having the second dorsal-fin insertion opposite the anal-fin midbase. It most closely resembles C. borneensis but differs in tooth morphology and counts and a number of morphological characters, including lack of enlarged hyomandibular pores which are diagnostic of C. borneensis. The historic range of C. obsolerus sp. nov. is under intense fishing pressure and this species has not been recorded anywhere in over 80 years. There is an urgent need to assess its extinction risk status for the IUCN Red List of Threatened Species. With so few known records, there is a possibility that Carcharhinus obsolerus sp. nov. has been lost from the marine environment before any understanding could be gained of its full historic distribution, biology, ecosystem role, and importance in local fisheries.
Vertebral and tooth count summaries for the genus Carcharhinus. Ranges for number of precaudal and total centra, and upper and lower teeth (with number of specimens included in range in parantheses) for members of the genus Carcharhinus. Species groupings follow a combination of information provided in  and molecular results in ; note these are only provisional subgroupings pending a more detailed phylogenetic revision of this genus. (XLSX)
The silvertip shark (Carcharhinus albimarginatus) is a reef-associated shark, with an intermittent distribution across the Indo-Pacific Ocean. Owing to global declines, the species is listed as Vulnerable under the International Union of Conservation for Nature Red List. Samples from 152 C. albimarginatus were collected from three locations: Papua New Guinea (PNG), east Australia and Seychelles. Samples were analysed using mitochondrial, microsatellite and double-digest restriction-associated DNA (ddRAD) generated single nucleotide polymorphism markers. As expected across a vast oceanic expanse, no gene flow was identified between south-west Pacific locations and Seychelles for any marker (population differentiation measured using ΦST values 0.92–0.98, FST values 0.036–0.059). Mitochondrial DNA indicated significant population structuring between PNG and east Australia (ΦST = 0.102), but nuclear markers suggested connectivity between these geographically close regions (FST = 0.000–0.001). In combination with known telemetry movements for C. albimarginatus, our results suggest stepping-stone patterns of movement between regions is likely driven by reproductive requirements. The use of three distinct marker types in this study has facilitated a powerful genetic description of the population connectivity of C. albimarginatus between the three sampled regions. Importantly, the connectivity described between PNG and east Australia should be used as a guide for managing the south-west Pacific stock of C. albimarginatus.
Our study is the first detailed examination of species composition using DNA COI barcoding of elasmobranchs from an artisanal fishery of Papua New Guinea. The study is the first in the region to provide biomass estimates based on species confirmation following examination of dried fins. Over 20 species of elasmobranchs were identified from 623 fins from the artisanal fishery in Milne Bay Province of PNG, with Carcharhinus amblyrhynchos and Carcharhinus melanopterus the most abundant species in the catches. Of concern, 21% of fins examined were from IUCN listed threatened species (Vulnerable or Endangered) with 8% of fins from the Endangered scalloped hammerhead (Sphyrna lewini). Following species identifications and use of species-specific length and weight extrapolations, we estimated over 9 t of elasmobranchs contributed to the fin batch. Importantly, the vast majority of the elasmobranchs in this batch were from immature animals. Genetic identification has an important role to play in the ongoing sustainable management of elasmobranchs in artisanal fisheries in PNG and more widely. However in the absence of ongoing genetic testing, recording the species (if known) at the time of catch is more achievable and would provide more robust data for fisheries managers in PNG over the longer term.
In this paper we combine analyses of satellite telemetry and molecular data to investigate spatial connectivity and genetic structure among populations of shortfin mako (Isurus oxyrinchus) in and around Australian waters, where this species is taken in recreational and commercial fisheries. Mitochondrial DNA data suggest matrilineal substructure across hemispheres, while nuclear DNA data indicate shortfin mako may constitute a globally panmictic population. There was generally high genetic connectivity within Australian waters. Assessing genetic connectivity across the Indian Ocean basin, as well as the extent that shortfin mako exhibit sex biases in dispersal patterns would benefit from future improved sampling of adult size classes, particularly of individuals from the eastern Indian Ocean. Telemetry data indicated that Australasian mako are indeed highly migratory and frequently make long-distance movements. However, individuals also exhibit fidelity to relatively small geographic areas for extended periods. Together these patterns suggest that shortfin mako populations may be genetically homogenous across large geographical areas as a consequence of few reproductively active migrants, although spatial partitioning exists. Given that connectivity appears to occur at different scales, management at both the national and regional levels seems most appropriate.
Coastal sharks with small body sizes may be among the most productive species of chondrichthyans. The Australian sharpnose shark (Rhizoprionodon taylori) is one of the most productive members of this group based on work in northern and eastern Australia. However, life history information throughout the remainder of its range is lacking. To address this knowledge gap, the age, growth and maturity of R. taylori caught in the Gulf of Papua prawn trawl fishery in Papua New Guinea, were studied. One hundred and eighty six individuals, comprising 131 females (31–66 cm TL) and 55 males (31–53 cm TL) were aged using vertebral analysis and growth was modelled using a multi-model approach. The lack of small individuals close to the size at birth made fitting of growth curves more difficult, two methods (fixed length at birth and additional zero aged individuals) accounting for this were trialled. The von Bertalanffy growth model provided the best fit to the data when used with a fixed length-at-birth (L0 = 26 cm TL). Males (L∞ = 46 cm TL, k = 3.69 yr⁻¹, L50 = 41.7 cm TL and A50 = 0.5 years) grew at a faster rate and matured at smaller sizes and younger ages than females (L∞ = 58 cm TL, k = 1.98 yr⁻¹, L5o = 47.0 cm TL and A50 = 0.93 years). However, none of the methods to account for the lack of small individuals fully accounted for this phenomenon, and hence the results remain uncertain. Despite this, the results reaffirm the rapid growth of this species and suggest that the Gulf of Papua population may grow at a faster rate than Australian populations. Rhizoprionodon taylori is possibly well placed to withstand current fishing pressure despite being a common bycatch species in the Gulf of Papua prawn trawl fishery. However, further research needs to be undertaken to estimate other key life history parameters to fully assess the population status of this exploited shark species and its vulnerability to fishing in the Gulf of Papua.
- Aug 2018
This study investigated variations in the composition and biomass of demersal fish assemblages over a 570-metre depth gradient on the temperate, lower west coast of Australia (32° S) in the south-eastern Indian Ocean. Fish assemblages were sampled using Baited Remote Underwater Stereo Video systems (stereo-BRUVs, n=284 deployments) from shallow waters around a mid-shelf island (Rottnest Island) to the continental slope within a submarine canyon (Perth Canyon). A total of 9013 individual fishes (i.e. ΣMaxN) belonging to 179 species and 75 families were identified. Multivariate statistical analyses revealed three distinct fish assemblages associated with the continental shelf (5–199 m), margin (200–300 m) and upper slope (300–570 m). A distance-based linear model revealed that among environmental covariates, benthic biota (sessile invertebrates and macroalgae) accounted for the highest proportion of variation in fish assemblage composition (16.9%) followed by depth (12.5%) and seabed relief (10.5%). Generalised additive models indicated higher biomass of fish associated with habitats characterised by benthic biota. Species richness decreased with increasing depth across the continental shelf but remained constant with increasing depth on the continental slope. Average fish length was not correlated with depth but was greatest at 200–400m depth. The continental margin and upper slope habitats revealed a distinct change in assemblage composition as well as a peak in biomass of species that was dominated by larger-bodied meso-predators at the continental margin. The trends exhibited in fish assemblage characteristics across this broad depth range can inform ecosystem based management for deepwater fisheries resources.
Question - Does DNA really help a taxonomy? Is morphology insufficient to define species?
I completely agree, but I do feel that we are now finding where some of these DNA approaches without morphological support are wrong so I am hoping this might start to concern people and force them away from that approach. Unfortunately the plethora of journals available these days means even the worst science can get published somewhere. That is a worrying trend
Question - Does DNA really help a taxonomy? Is morphology insufficient to define species?
Completely agree Dalmiro - an integrated approach is the only way to go. Only way you will find discordance. Understanding where we have discordance will lead to research in future which can properly explain why we are getting that discordance rather than just sweeping it under the rug
Question - Does DNA really help a taxonomy? Is morphology insufficient to define species?
Here is one of latest papers which highlights how DNA barcoding can be very misleading. But more detailed genetic analyses, particularly including nuclear exon data, combined with morphological examination managed to resolve this 'complex' of chimaeras despite huge discordance between mtDNA and morphological data. Using DNA barcoding to support species delineation is valid; using it without or with lack of morphological data is bad science and helps no one except the author obtain another paper
An annotated checklist of the chondrichthyan fishes (sharks, rays, and chimaeras) of Papua New Guinean waters is herein presented. The checklist is the result of a large biodiversity study on the chondrichthyan fauna of Papua New Guinea between 2013 and 2017. The chondrichthyan fauna of Papua New Guinea has historically been very poorly known due to a lack of baseline information and limited deepwater exploration. A total of 131 species, comprising 36 families and 68 genera, were recorded. The most speciose families are the Carcharhinidae with 29 species and the Dasyatidae with 23 species. Verified voucher material from various biological collections around the world are provided, with a total of 687 lots recorded comprising 574 whole specimens, 128 sets of jaws and 21 sawfish rostra. This represents the first detailed, verified checklist of chondrichthyans from Papua New Guinean waters.
Catch composition, landing patterns and biological aspects of sharks caught by commercial fishing fleet operating in the Andaman Sea were recorded from landing sites in Ranong province of Thailand over a period of 1 year. Of the 64 species previously reported in the existing Thailand checklist, only 17 species were recorded in this study. Shark landings from the Andaman Sea appear now to be dominated largely by bamboo sharks Chiloscyllium spp. (Hemiscylliidae), which contribute c. 65% of the total number of sharks recorded. The carcharhinid sharks comprised c. 30·5% to the total catch, while the remaining c. 4·5% of landings comprised sharks from the families Squalidae, Stegostomatidae, Sphyrnidae and Triakidae. The catch composition is remarkably different from the previous landing survey in 2004, in that the current study found noticeable declines in landings of slow‐growing, late‐ maturing and low‐fecundity species (especially sphyrnid and carcharhinid species). The absences of many species and changes in life‐stage composition suggest that the populations of these groups may be close to collapse. The results from this study emphasize the urgency for additional research and monitoring efforts and also the need for management incentives in order to manage shark fisheries effectively in the Andaman Sea.
An integrated taxonomic approach, combining both morphological and molecular data, was adopted to investigate the Hydrolagus lemures-ogilbyi group in the Indo-Australian region. Single mitochondrial markers (CO1 and NADH2) provided evidence supporting the separation of four distinct species in this group. However, detailed morphological data collected from specimens from across their range failed to find any consistent differences, and many features previously considered to be diagnostic were found to be variable. Nuclear DNA data also failed to support the differences found with the single mitochondrial markers and, together with the morphological data, supported the hypothesis that only a single species in this group is present in the Indo-Australian region. In addition, the results failed to support the current generic placement of this group in Hydrolagus, suggesting they belong to the genus Chimaera with doubt over the validity of Hydrolagus as a valid genus. The oldest available name for this group is Chimaera ogilbyi and a redescription is provided. This species occurs throughout Australia, eastern Indonesia (Java, Bali, and Lombok) and northern Papua New Guinea.
Leslie matrix models are an important analysis tool in conservation biology that are applied to a diversity of taxa. The standard approach estimates the finite rate of population growth (λ) from a set of vital rates. In some instances, an estimate of λ is available, but the vital rates are poorly understood and can be solved for using an inverse matrix approach. However, these approaches are rarely attempted due to pre-requisites of information on the structure of age or stage-classes. This study addressed this issue by using a combination of Monte Carlo simulations and the sample-importance-resampling (SIR) algorithm to solve the inverse matrix problem without data on population structure. This approach was applied to the grey reef shark (Carcharhinus amblyrhynchos) from the Great Barrier Reef (GBR) in Australia to determine the demography of this population. Additionally, these outputs were applied to another heavily fished population from Papua New Guinea (PNG) that requires estimates of λ for fisheries management. The SIR analysis determined that natural mortality (M) and total mortality (Z) based on indirect methods have previously been overestimated for C. amblyrhynchos, leading to an underestimated λ. The updated Z distributions determined using SIR provided λ estimates that matched an empirical λ for the GBR population and corrected obvious error in the demographic parameters for the PNG population. This approach provides opportunity for the inverse matrix approach to be applied more broadly to situations where information on population structure is lacking. This article is protected by copyright. All rights reserved.
In the central west Pacific region, silky sharks (Carcharhinus falciformis) are commonly taken in fisheries, forming up to 95% of incidental elasmobranch bycatch. The present study examined the life history of silky sharks (n=553) from Papua New Guinean waters. Age was analysed using sectioned vertebrae, and a multimodel approach was applied to the length-at-age data to fit growth models. Females ranged in length from 65.0- to 253.0-cm total length (TL), with the oldest estimated at 28 years. Males ranged in length from 68.4 to 271.3cm TL and were aged to a maximum of 23 years. The logistic model provided the best fitting growth parameter estimates of length at birth L0=82.7cm TL, growth coefficient g=0.14year⁻¹ and asymptotic length L∞=261.3cm TL for the sexes combined. Females reached sexual maturity at 204cm TL and 14.0 years, whereas males reached maturity at 183cm TL and 11.6 years. The average litter size from 28 pregnant females was 8 (range of 3-13). The growth parameters and late ages of sexual maturation for silky sharks in the central west Pacific suggest a significant risk from fisheries exploitation without careful population management.
The narrow sawfish Anoxypristis cuspidata belongs to the most endangered family of chondrichthyan fishes, the sawfishes (Pristidae). This species has undergone significant de - clines in geographic range and abundance due to anthropogenic activities including fishing and habitat destruction. Very little is known of adult movements within its distribution. In order to better manage and protect this endangered species, understanding patterns of habitat use, connectivity and behaviour is important. Using a combination of partial mitochondrial sequences (control region [CR] and NADH dehydrogenase 4 [ND4]) and nuclear markers (microsatellites), this study assessed the genetic population structure of A. cuspidata in Australia and Papua New Guinea. Significant population structuring using mitochondrial DNA was found between the east Australian coast, Gulf of Papua and Gulf of Carpentaria (using concatenated CR and ND4 markers) (analysis of molecular variance [AMOVA], ΦST = 0.082, p = < 0.001). In contrast, no population structure was evident across northern Australia using nuclear microsatellite loci (FST = 0.012, p = 1.000). Our results suggest that a combination of historic genetic drift, maternal natal philopatry and possible male-biased dispersal likely drive the genetic patterns observed. Given the endangered status and lack of knowledge for A. cuspidata, this study presents important insights that may be used to inform management efforts.
This study assessed the presence and prevalence of multiple paternity (MP) in litters of grey reef sharks (Carcharhinus amblyrhynchos) and scalloped hammerheads (Sphyrna lewini) opportunistically caught in Papua New Guinea (PNG). Litter size between species were significantly different with an average of 3.3 pups for grey reef sharks and 17.2 pups for scalloped hammerhead. Using 14 and 10 microsatellite loci respectively, we identified MP in 66% of grey reef sharks (4 out of 6 litters) and 100% MP in scalloped hammerheads (5 litters). We found high paternal skew (the uneven contribution of sires per litter) and a positive correlation between female adult size and litter size in scalloped hammerheads but not in grey reef sharks. Differences in the frequency of MP between species and the identification of paternal skew may be linked with mating strategies and post-copulatory mechanisms. Multiple paternity is thought to benefit populations by enhancing genetic diversity therefore increasing the population’s genetic resilience to extrinsic pressures. The identification of MP in two shark species reported here, further elucidates the complex breeding strategies elasmobranchs undertake.
Centrophorus specimens with a distinctive long-based first dorsal fin (long-finned species) have previously been considered to be Centrophorus lusitanicus first described from Portugal. Critical examination of the original description and illustration reveal that C. lusitanicus should be considered a junior synonym of C. granulosus. However, the specimen considered to be the syntype of C. lusitanicus in the Natural History Museum in London is clearly a long-finned species and not conspecific with C. granulosus. A more detailed investigation revealed that this specimen should not be considered a syntype and was likely not originally collected off the coast of Portugal. Investigation of long-finned specimens of Centrophorus from the Indo-West Pacific and Eastern Atlantic revealed that two undescribed species exist and are herein formally described as C. lesliei and C. longipinnis. The two species are similar morphologically and belong to the long- snout Centrophorus group (e.g. C. isodon and C. harrissoni) but are clearly separable based on their very long first dorsal fins. The two species differ in relative length of the first dorsal fin and several other characters. They also differ genetically. Nonmetric multidimensional ordination based on morphometric data reveals both species level and ontogenetic differences. A short erratum is also provided for Part 1 of this revision of the Centrophorus due to two figure related errors which may cause some confusion.
Question - Any Idea what kind of shark the pictured one is?
only other option is one of the Iago complex but dorsal fin not far enough forward
- Sep 2017
Apristurus yangi, a new species of deepwater catshark, is described from Papua New Guinea based on two specimens collected during recent deepwater surveys. The new species belongs to the longicephalus-group which is characterised by its very long snout compared to members of the brunneus-group and spongiceps-groups. Apristurus yangi differs from its closest congeners in a combination of the following characters: 8 intestinal spiral valves; mouth width 7.9–8.6% TL; 32–33 monospondylous centra; 38 precaudal-diplospondylous vertebrae; small in size (female holotype mature at 437 mm TL); egg case small (~5.9 cm long) and with faint longitudinal striations.
Descriptions of the egg cases of Dentiraja polyommata (n = 16) and Asymbolus pallidus (n = 44) are provided from egg cases collected from a commercial trawl fishery off Swain Reefs, central Queensland, Australia. Egg cases of D. polyommata are rectangular, convex and golden-tan in colour and those of A. pallidus elongate, vase-shaped and golden. To determine if a comparative statistical non-metric multi-dimensional scaling approach could identify egg cases of species taken in the same region and fishery, egg cases were compared with the skate D. endeavouri and catsharks A. analis, A. rubiginosus and Figaro boardmani. The statistical approach clearly discriminated the species based on five proportional measurements and identified the morphometrics that separated genera and species. This approach is valuable in a fisheries context for accurate identification of visually similar egg cases that can assist management of oviparous chondrichthyans. A rare incidence of intraspecific chondrichthyan cannibalism was noted for A. pallidus males that consumed egg cases of their own species.
Information on how shark populations respond to fishing mortality (F) is critical to developing successful management and conservation strategies. However, data on catch, fishing effort and species abundance are often lacking for shark populations – preventing stock assessments from being conducted. Static demographic models circumvent this issue as they only require life history parameters. Age-structured Leslie Matrix models were developed and applied for silvertip shark Carcharhinus albimarginatus and common blacktip shark Carcharhinus limbatus sampled from heavily fished populations in the Indo-Pacific. Stochasticity was introduced to these models by varying vital rates though Monte Carlo simulations. Varying levels of F were introduced to the analyses to determine how both species respond to fishing pressure. Management scenarios were further developed to determine strategies that could facilitate sustainable harvesting. The demographic estimates demonstrated that without fishing both species would have increasing populations (λ = 1.06 yr⁻¹ for C. albimarginatus and 1.05 yr⁻¹ for C. limbatus) until density dependent effects occur. However, both populations would decline when low levels of F (>0.1 yr⁻¹) were applied to all age-classes. The matrix elasticities revealed that changes to fertility elements had little effect on λ, while changes in juvenile survival led to the largest changes. However, age-at-first-capture analysis suggests protecting the juvenile life stage of both species would be an ineffective management strategy as both species mature at old ages. An age-at-last-capture analysis suggests these species could be harvested while maintaining increasing populations through a gauntlet fishery. This required F to be restrained to individuals <100 cm TL while protecting the older age-classes to preserve the breeding stock. This strategy would allow up to 16% and 13% of this size class to be harvested for C. limbatus and C. albimarginatus, respectively, until density dependent effects begin to manifest. However, this strategy depends on the ability to successfully protect all other age-classes from fishing – a strategy that may not be pragmatic in developing nations where little regulation occurs.
Conservation and management of migratory species can be complex and challenging. International agreements such as the Convention on Migratory Species (CMS) provide policy frameworks, but assessments and management can be hampered by lack of data and tractable mechanisms to integrate disparate datasets. An assessment of scalloped (Sphyrna lewini) and great (Sphyrna mokarran) hammerhead population structure and connectivity across northern Australia, Indonesia and Papua New Guinea (PNG) was conducted to inform management responses to CMS and Convention on International Trade in Endangered Species listings of these species. An Integrated Assessment Framework (IAF) was devised to systematically incorporate data across jurisdictions and create a regional synopsis, and amalgamated a suite of data from the Australasian region. Scalloped hammerhead populations are segregated by sex and size, with Australian populations dominated by juveniles and small adult males, while Indonesian and PNG populations included large adult females. The IAF process introduced genetic and tagging data to produce conceptual models of stock structure and movement. Several hypotheses were produced to explain stock structure and movement patterns, but more data are needed to identify the most likely hypothesis. This study demonstrates a process for assessing migratory species connectivity and highlights priority areas for hammerhead management and research.
A new species of lanternshark, Etmopterus samadiae (Squaliformes: Etmopteridae), is described from off northern Papua New Guinea, in the western Central Pacific Ocean. The new species resembles other members of the “Etmopterus lucifer” clade in having linear rows of dermal denticles and most closely resembles E. brachyurus from the western North Pacific. The new species occurs along insular slopes between 340 and 785 m depth. The new species can be distinguished from other members of the E. lucifer clade by a combination of characteristics, including length of anterior flank branch mark- ings being slightly shorter than its posterior branch, a longer caudal base marking, and irregular and variable number of black, horizontal, dash-like marks on sides of body. Molecular analysis based on the NADH2 marker further supports the distinction of E. samadiae from other members of the E. lucifer clade.
- Mar 2017
A new arhynchobatin skate, Notoraja sereti n. sp., is described based on three specimens collected from off Madang (Papua New Guinea) at depths of 800–980 m. This medium-size Notoraja skate shares with other velcro skates from the Western Pacific, N. alisae, N. fijiensis, N. inusitata and N. longiventralis, a ventral surface covering of fine denticles giving the skin a velvety feel. Notoraja sereti differs from all of these species in having a shorter snout (preorbital length 10.1–11.1 vs. 11.5–14.5% TL, prenasal length 8.2–8.9 vs, 9.8–12.1% TL), shorter head (dorsal head length 15.2–16.2 vs. 17.1–19.3% TL, ventral head length 21.6–22.9 vs. 22.9–25.9% TL), fewer pectoral-fin radials (total radials 58–60 vs. 61–74), and fewer vertebrae (predorsal diplospondylous centra 66–71 vs. 72–82, predorsal centra 90–95 vs. 98–107, total centra 126–131 vs. 135–152).
DNA sequence data from mitochondrial genomes and c. 1000 nuclear exons were analysed for a complete taxon sampling of manta and devilrays (Mobulidae) to estimate a current molecular phylogeny for the family. The result- ing inferences were combined with morphological information to adopt an integrated approach to resolving the taxonomic arrangement of the family. The members of the genus Manta were found to consistently nest within the Mobula species and consequently the genus Manta is placed into the synonymy of Mobula. Mobula eregoodootenkee, M. japanica and M. rochebrunei were each found to be junior synonyms of M. kuhlii, M. mobular and M. hypostoma, respectively. The mitochondrial and nuclear tree topologies were in agreement except for the placement of M. tara- pacana which was basal to all other mobulids in the nuclear exon analysis, but as the sister group to the M. alfredi– M. birostris–M. mobular clade in the mitochondrial genome analysis. Results from this study are used to a revise the taxonomy for the family Mobulidae. A single genus is now recognized (where there were previously two) and eight nominal species (where there were previously 11).
Small-scale shark fisheries in Papua New Guinea have developed rapidly and are largely unmanaged. While shark species are vulnerable to overexploitation, local fishers who depend on shark fin for income also have limited alternative income options. This implies a difficult trade-off for policy makers between conservation and community welfare. A case study of shark fishing activities in the Louisiade Archipelago of the Milne Bay Province, a major small-scale shark fin producing region, is presented to inform such trade-offs. The region has experienced a significant reduction in available income opportunities due to the recent closure of the local sea cucumber fishery in 2009. While it had been widely assumed that shark fin production and income was likely to have escalated in the region to replace lost sea cucumber income, our model of small-scale shark fin production shows that quarterly dried fin production was in fact, on average, 68 kg higher while the sea cucumber fishery operated (holding all else constant). Furthermore, annual shark fin income is estimated to have fallen by 75% following the sea cucumber fishery closure. Falling prices and a decline in market access resulting from the closure of the sea cucumber fishery appear to be the major drivers of the fall in shark fin production. These factors have been accentuated by the geographical isolation of Louisiade communities, high fuel costs and the low economic returns associated with the sale of shark fin (relative to sea cucumber). The influence of market access on shark fin production is also reflected in the modelled increase in shark fin production (119 kg per quarter on average) that occurred with the introduction of a transport boat in the region. Market access is likely to further improve, particularly if the sea cucumber fishery is reopened and/or shark fin prices increase. Therefore, low-cost, community-based management of shark resources based on the allocation of allowable shark catches to ward communities is recommended. Such an approach takes advantage of the communal characteristics of the local island communities as well as the fishery data collection and monitoring mechanisms that are already being used by the local government.
Growth and maturity of the silvertip shark Carcharhinus albimarginatus from Papua New Guinea were estimated to form the basis of future population assessments. Samples were collected from commercial longline vessels targeting sharks in the Bismarck and Solomon Seas. A total of 48 C. albimarginatus—28 males (95–219 cm total length, TL) and 20 females (116–250 cm TL)—provided data for the analyses. Employing back-calculation techniques accounted for missing juvenile length classes and supplemented the sample size. A multi-model framework incorporating the Akaike information criterion was used to estimate growth parameters. The von Bertalanffy growth function (VBGF) provided the best-fit growth estimates. Parameter estimates were L0 = 72.1 cm TL, k = 0.04 yr−1 and L∞ = 311.3 cm TL for males; and L0 = 70.8 cm TL, k = 0.02 yr−1 and L∞ = 497.9 cm TL for females. The biologically implausible L∞ occurred for females as their growth did not asymptote; a typical trait of large shark species. The maximum age estimated from vertebral analysis was 18 yr for both sexes, while the calculated longevity from the VBGF parameters was 27.4 yr for males and 32.2 yr for females. Males matured at 174.7 cm TL and 10.5 yr old, while females matured at 208.9 cm TL and 14.8 yr old.
- Jan 2017
The status of sawfishes (family Pristidae), and indeed most sharks and rays, in Papua New Guinea (PNG) is largely unknown due to the paucity of detailed catch and observational records available, both historic and contemporary. This paper provides the first comprehensive review of the published and unpublished literature on sawfish records in PNG. It also collates information for all sawfish specimens in the holdings of museum and fisheries collections, dating back to the late 1800s. Opportunistic sampling during a shark and ray biodiversity project in PNG has resulted in contemporary records for all 4 sawfish species known to occur in the region (i.e. Anoxypristis cuspidata, Pristis clavata, P. pristis and P. zijsron) and identification of suitable habitat for the species across PNG. A review of the literature shows that declines in sawfish populations have occurred in a number of locations. Detailed surveys of the key areas highlighted in this study are urgently required to assess the current status of sawfish in PNG. This information is crucial for developing a global strategy for sawfish conservation and fisheries management, given the apparent persistence of all 4 Indo-Pacific species in PNG.
Sharks and rays are facing increasing anthropogenic pressure globally, including in the Pacific. However, data on their status and biodiversity are lacking for many Pacific Large Ocean Island States. This study aimed to construct a species checklist for the sharks and rays occurring in the Solomon Islands, review the human interactions with these species, and present a synthesis of their conservation status. Given the paucity of available data, a wide range of data sources were used including fisheries data, citizen science, and ethnobiological studies. Results were validated through a review process involving expert informants. Fifty sharks and rays were identified from the Solomon Islands, of which 20 are assessed as Vulnerable or Endangered on the IUCN Red List, 10 in the Convention on International Trade in Endangered Species, and 11 in the Convention for Migratory Species. The checklist also presents an eastwards range extension for the Endangered dwarf sawfish Pristis clavata. Fishing appears to be the main impact, though impacts from habitat loss and degradation are possible. This study provides a systematic synthesis and review of the biological diversity, uses, and cultural significance of Solomon Islands sharks and rays, and describes a process for assembling species checklists and reviews in data-poor contexts. However, this synthesis is based on limited information and a complete assessment of shark and ray status in the Solomon Islands will require primary fieldwork.
- Dec 2016
A new species of catshark, provisionally placed in the genus Galeus, is described from Papua New Guinea based on 7 specimens collected during recent deepwater surveys of the region. The new species, Galeus corriganae, is closest to G. priapus from New Caledonia and G. gracilis from northwestern Australia but differs in several morphological characters. A reclassification of the catshark groups is required to revise the familial and generic arrangement of the group.
The first illustrated guide to the over 630 known species of rays found on the planet. Rays are among the largest fishes and evolved from shark-like ancestors nearly 200 million years ago. Rays of the World is the first complete pictorial atlas of the world's ray fauna and includes information on many species only recently discovered by scientists while undertaking research for the book. It includes all 26 families and 633 valid named species of rays, but additional undescribed species exist for many groups. Rays of the World features a unique collection of paintings of all living species by Australian natural history artist Lindsay Marshall. This comprehensive overview of the world's ray fauna summarises information such as general identifying features and distributional information about these iconic but surprisingly poorly known fishes. It will enable readers to gain a better understanding of the rich diversity of rays and promote wider public interest in the group. Rays of the World is an ideal reference for a wide range of readers, including conservationists, fishery managers, scientists, fishers, divers, students and book collectors. Available as an eBook December 2016 800 pages, Hardback ISBN: 9780643109131 $220.00 Members of the family Rajidae, known as skates or hardnose skates, are small to very large rays (adults 33 cm to more than 2 m TL) with a depressed body, almost circular to rhombic disc, and pectoral-fin apices broadly rounded to angular. A firm, slender tail is well demarcated from the disc. The snout is more or less elongated and pointed, supported by a stiff rostral cartilage, and often has a short lobe at its tip. The anterior nasal flaps are expanded to form an incomplete nasal curtain. These flaps usually reach the mouth but their posterior margins are not joined like some other ray groups, such as the stingrays. Pelvic fins are notched with distinct anterior and usually larger posterior lobes. Two small dorsal fins are located near the end of the tail and their bases are often joined. The caudal fin is greatly reduced in size with the lower lobe (when present) smaller than the upper lobe. The skin is sometimes naked, but the disc and tail are usually partly covered with dermal denticle patches, particularly along the anterior disc margins. Thorns, usually present on the upper disc of juveniles (and most adults), are variably located on the orbital rims (around upper half of eye), nuchal (nape) and scapular (shoulder) regions, and along the median disc and tail (additional lateral thorn rows on the tail of several species). Adult males have a well-defined, longitudinally arranged patch of retractable alar thorns on the mid-outer regions of each pectoral fin, and some species have additional anteriorly positioned thorn patches, known as malar thorns. The family includes at least 154 valid described species in 17 genera: Amblyraja,
A new species of guitarfish (Rhinobatos) is described based on a single specimen collected in 2014 from off New Ireland in Papua New Guinea. This specimen represents the first record of the family Rhinobatidae in Papua New Guinean waters. Based on molecular data, the new species appears to be most similar to Rhinobatos whitei (Philippines) and Rhinobatos sainsburyi (northern Australia), but is distinguished based on its coloration, morphology and certain meristic characters.
The genus Lamiopsis (Carcharhinidae) was previously considered to be monotypic, containing only the Broadfin Shark Lamiopsis temminckii (Müller & Henle, 1839) widely distributed in the Indo–West Pacific. However, a recent taxonomic study revealed that the Western Central Pacific populations were a separate species and that L. temminckii was restricted to the northern Indian Ocean. In this study, the paucity of data available for the true L. temminckii was highlighted. Recently collected specimens of L. temminckii has allowed for a detailed redescription of this species from the northern Arabian Sea to complement the previous taxonomic work on this genus
- Sep 2016
The Roughskin Dogfish Centroscymnus owstonii is one of the most widespread deepwater shark species, but its global distribution is mostly based on patchy records. In this study, C. owstonii was reinvestigated with focus on its poorly known distribution in the western and eastern Indian Ocean. Previous records of the species from the Seychelles, which, for decades, were considered to be of a different species, were verified in this study. Furthermore, the first records from off Reunion Island, Madagascar, and Indonesia are provided, including the smallest free-swimming specimen of the species described in detail to date. Based on these specimens, a description of C. owstonii is given with updated and extended morphometric data, photographic documentation and scanning electron microscopy (SEM) images of dermal denticles. Additionally, specimens from the Indian Ocean are compared with specimens from the Pacific and Atlantic Oceans. For the Pacific Ocean, the first record from the central western North Pacific is provided from the Hawaiian-Emperor seamount chain. This record also represents the most open ocean known occurrence of C. owstonii. © 2015 Senckenberg Gesellschaft für Naturforschung and Springer-Verlag Berlin Heidelberg
Three undescribed stingrays were discovered as part of a broader revision of the family Dasyatidae that formed part of the Chondrichthyan Tree of Life project. This research forms part of a sequence of papers on rays aimed at describing unnamed species for inclusion in a multi-authored guide to rays of the world. The first part of this series focused on a redefinition of genera of the family Dasyatidae. The new Indo-West Pacific taxa are represented by separate genera from three dasyatid subfamilies: Himantura australis sp. nov. (northern Australia and Papua New Guinea), Taeniura lessoni sp. nov. (Melanesia) and Telatrygon biasa sp. nov. (Indo-Malay Archipelago). Himantura australis sp. nov., which belongs to a complex of four closely related reticulate whiprays, differs subtly from its congeners in coloration, morphometrics and distribution. Taeniura lessoni sp. nov. is the second species in a genus containing the widely-distributed T. lymma, which is possibly the most abundant stingray in shallow coral-reef habitats of the Indo-Pacific, with the new species apparently restricted to Melanesia. Taeniura lessoni sp. nov. is distinguishable by the absence of a distinctive pair of vivid blue longitudinal stripes on the dorsolateral edges of the tail which is one of the most distinctive features of T. lymma. Telatrygon biasa sp. nov. belongs to a small, recently designated genus of stingrays represented by four species in the tropical Indo-West Pacific. Telatrygon biasa sp. nov. differs from these species in morphometrics. The new species differs markedly from T. zugei in its NADH2 sequence. Telatrygon crozieri is resurrected as a valid northern Indian Ocean representative of the T. zugei complex.
The Mumburarr Whipray, Urogymnus acanthobothrium sp. Nov. is described from a single specimen taken from the Cambridge Gulf, Western Australia, and from images of 10 other specimens from northern Australia and Papua New Guinea (all observed but not collected). It is a very large ray that attains at least 161 cm disc width, making it amongst the largest of the whiprays. The ventral tail below the caudal sting has a low, short-based fold. A ventral tail fold (or a dorsal fold) has not been recorded for any other himanturin stingray in the Indo-West Pacific. Molecular data suggest it is most closely related to a similar but more widely distributed cognate, U. granulatus. Both of these species share a suboval disc shape, similar squamation patterns, and the tail posterior to the sting is entirely white (at least in small individuals). U. acanthobothrium sp. Nov. differs from U. granulatus in having a longer and more angular snout, longer tail, more posteriorly inserted caudal sting, lacks white flecks on the dorsal surface, and the ventral disc is uniformly white (rather than white with a broad black margin). It co-occurs with two other morphologically distinct Urogymnus in the region (U. asperrimus and U. dalyensis). Like U. dalyensis it occurs in both brackish and marine waters. A key is proved to the members of the genus Urogymnus.
- Jul 2016
Molecular and morphological data show that the pelagic eagle rays of the genus Aetobatus form a distinct family-level grouping separate from the true eagle rays, Aetomylaeus and Myliobatis (family Myliobatidae). The family Aetobatidae is herein resurrected to include the pelagic eagle rays and definitions are provided for this family and for the Myliobatidae. The key characters separating Aetobatidae from Myliobatidae are: pectoral fins joining head at level of eyes (vs. below level of eyes), internasal flap deeply notched (vs. nearly straight), free rear tip of pectoral fins broadly rounded (vs. angular), spiracles dorsolateral on head and visible in dorsal view (spiracles lateral on head and not visible in dorsal view), dorsal fin with obvious free rear tip (vs. no free rear tip evident, posterior margin joining dorsal surface of tail).
A new species of numbfish, Narcine baliensis, sp. nov., is described from the tropical eastern Indian Ocean from Indonesia. It is superficially similar to N. brevilabiata and N. atzi in aspects of its color pattern, but is distinguished from both congeners in details of its color pattern, in tooth band morphology, and in proportions of its dorsal fins, among other features. Narcine baliensis, sp. nov., is unique in having a dorsal color pattern composed of large, circular, ovoid or elongate dark brown spots or blotches on dorsal disc along with more numerous small (about eye-sized or slightly greater) brownish, subcircular spots, with large blotches and small spots surrounded by a very slender creamy-white pattern, as well as in having broadly circular upper and lower tooth bands of about the same width and shape. The genus Narcine is now composed of 20 valid species, but uncertainty remains concerning the identification and morphological variation of some of its species in the tropical Indo-West Pacific region.
A new species of fanray (Platyrhina) is described based on four specimens collected in 2015 from the Andaman Sea, off Myanmar. These represent the first records of the family Platyrhinidae from the Indian Ocean with the three other mem-bers of the genus being restricted to the North-West Pacific. The new species differs from its congeners in having a series of faint dark bands on the body and tail, more pectoral-fin radials, and much more widely separated dorsal fins.
The checklist of Chondrichthyan fishes of the Great Barrier Reef provides an up-to-date account of the diversity of sharks, rays and chimaeras in the Great Barrier Reef World Heritage Area (GBRWHA). This checklist has been compiled using literature searches, fisheries catch data and scientific data - both historical and contemporary - to compile a full species list, including conservation status from the current IUCN Red List. The GBRWHA includes all habitats from the estuarine and coastal zone, across the continental shelf to the continental slope to a depth of 200 m, along the coast of the Great Barrier Reef. Exact boundary coordinates for the GBRWHA are available from the Great Barrier Reef Marine Park Authority. This checklist is a WORKING DOCUMENT that will periodically be updated as our understanding of taxonomy and distribution improve, and as conservation listings (e.g. IUCN assessments) are updated over time. Much of this work is based on Last and Stevens (2009) which remains a key reference for shark and ray scientists
The deepwater chondrichthyan fauna of the Great Barrier Reef is poorly known and life history information is required to enable their effective management as they are inherently vulnerable to exploitation. The chondrichthyan bycatch from the deepwater eastern king prawn fishery at the Swain Reefs in the southern Great Barrier Reef was examined to determine the species present and provide information on their life histories. In all, 1533 individuals were collected from 11 deepwater chondrichthyan species, with the Argus skate Dipturus polyommata, piked spurdog Squalus megalops and pale spotted catshark Asymbolus pallidus the most commonly caught. All but one species is endemic to Australia with five species restricted to waters offshore from Queensland. The extent of life history information available for each species varied but the life history traits across all species were characteristic of deep water chondrichthyans with relatively large length at maturity, small litters and low ovarian fecundity; all indicative of low biological productivity. However, variability among these traits and spatial and bathymetric distributions of the species suggests differing degrees of resilience to fishing pressure. To ensure the sustainability of these bycatch species, monitoring of their catches in the deepwater eastern king prawn fishery is recommended.
Deepwater chondrichthyans known to occur in the Great Barrier Reef Marine Park. Source: A. Great Barrier Reef Marine Park (Chin et al. 2010); B. Eastern King Prawn fishery in the Great Barrier Reef, Department of Agriculture and Fishery Observer Program 2005–2010(Pears et al. 2012); C. Eastern King Prawn fishery in the Swain Reefs area of the Great Barrier Reef (the present study). Australian endemic: if endemic it is stated if restricted to waters offshore from Queensland-New South Wales (QLD-NSW) or Queensland (QLD). IUCN Status from the IUCN Red List of Threatened Species http://www.iucnredlist.org. (DOCX)
Depth and distribution range of deepwater chondrichthyans observed from Swain Reefs Eastern King Prawn Fishery. Australian endemic: if endemic it is stated if restricted to waters offshore from Queensland-New South Wales (QLD-NSW) or Queensland (QLD). Source: Last and Stevens, 2009. (DOCX)
Genetic samples for deepwater chondrichthyan specimens collected from Swain Reefs Eastern King Prawn Fishery. The GN numbers refer to samples with NADH2 sequences available as part of the Chondrichthyan Tree of Life project (http://sharksrays.org/). (DOCX)
Age and growth data for Dipturus polyommata, Squalus megalops and Mustelus walkeri. The growth completion rate k is the von Bertalanffy growth function. Note: M. walkeri male age at maturity was based on the largest adolescent male and the one mature male collected. Source: Rigby et al. 2105, Rigby et al. 2016. (DOCX)
Fisheries observer programs are used around the world to collect crucial information and samples that inform fisheries management. However, observer error may misidentify similar-looking shark species. This raises questions about the level of error that species misidentifications could introduce to estimates of species' life history parameters. This study addressed these questions using the Grey Reef Shark Carcharhinus amblyrhynchos as a case study. Observer misidentification rates were quantified by validating species identifications using diagnostic photographs taken on board supplemented with DNA barcoding. Length-at-age and maturity ogive analyses were then estimated and compared with and without the misidentified individuals. Vertebrae were retained from a total of 155 sharks identified by observers as C. amblyrhynchos. However, 22 (14%) of these were sharks were misidentified by the observers and were subsequently re-identified based on photographs and/or DNA barcoding. Of the 22 individuals misidentified as C. amblyrhynchos, 16 (73%) were detected using photographs and a further 6 via genetic validation. If misidentified individuals had been included, substantial error would have been introduced to both the length-at-age and the maturity estimates. Thus validating the species identification, increased the accuracy of estimated life history parameters for C. amblyrhynchos. From the corrected sample a multi-model inference approach was used to estimate growth for C. amblyrhynchos using three candidate models. The model averaged length-at-age parameters for C. amblyrhynchos with the sexes combined were [Formula: see text] = 159 cm TL and [Formula: see text] = 72 cm TL. Females mature at a greater length (l50 = 136 cm TL) and older age (A50 = 9.1 years) than males (l50 = 123 cm TL; A50 = 5.9 years). The inclusion of techniques to reduce misidentification in observer programs will improve the results of life history studies and ultimately improve management through the use of more accurate data for assessments.
Fishes are one of the most intensively studied marine taxonomic groups yet cryptic species are still being discovered. An integrated taxonomic approach is used herein to delineate and describe a new cryptic seamoth (genus Pegasus) from what was previously a wide-ranging species. Preliminary mitochondrial DNA barcoding indicated possible speciation in Pegasus volitans specimens collected in surveys of the Torres Strait and Great Barrier Reef off Queensland in Australia. Morphological and meristic investigations found key differences in a number of characters between P. volitans and the new species, P. tetrabelos. Further mt DNA barcoding of both the COI and the slower mutating 16S genes of additional specimens provided strong support for two separate species. Pegasus tetrabelos and P. volitans are sympatric in northern Australia and were frequently caught together in trawls at the same depths.
Configuration of external plates in Pegasus volitans. (A) dorsal and (B) ventral views taken from . Abbreviations for head, body and tail plates (all plates are paired except where noted) taken from : a = anal plate; ca.d. = dorsal ridge; ca.dl. = dorsolateral ridge; ca.vl. = ventrolateral ridge; cd1–11 = caudodorsal plates; cll–6 = caudolateral plates; ct = cleithrum; cv1–11 = caudoventral plates; d1–3 = dorsal plates; dll–4 = dorsolateral plates; ect = ectethmoid; f.p.v. = ventral-fin foramen; fr = frontal; g = gular plate; ip = interpectoral plate (unpaired); iv = interventral plate (unpaired); met = mesethmoid (unpaired); na = nasal (paired elements fused on midline); p = pectoral plate; pa = preanal plate (unpaired); pp.s. = superior pectoral-fin plate; pp.i. = inferior pectoral-fin plate; td = terminal-dorsal plate (unpaired); tl = terminal-lateral plate; tv = terminal-ventral plate (unpaired); v = ventral plate; vll–5 = ventrolateral plates. (TIF)
- Feb 2016
The bluespotted maskray, Neotrygon kuhlii (Muller & Henle, 1841), once thought to be widely distributed in the Indo-West Pacific, consists of a complex of several species and the type series consists of multiple species; its nomenclature is discussed. A lectotype and paralectotype are designated and the species rediagnosed based on the types and a fresh specimen from Honiara (Solomon Islands), near to the collection locality of the lectotype (Vanikoro, Solomon Islands). Molecular and morphological data provide confirmatory evidence that this maskray is distinct from some other regional forms. Three members of the complex from the Western Pacific identified in earlier studies are confirmed to be new species; Neotrygon australiae sp. nov. (Australia, New Guinea and eastern Indonesia), N. caeruleopunctata sp. nov. (Indian Ocean), and N. orientale sp. nov. (North-West Pacific). These species differ from each other and N. kuhlii in their adult size, anterior angle of the disc, number and distribution of blue spots on the dorsal disc, and other more subtle morphometric and meristic characters. Another largely plain-coloured Neotrygon, also currently misidentified as N. kuhlii, is sympatric with N. orientale sp. nov. in the South China Sea and off Taiwan. Neotrygon varidens (Garman) is resurrected as the valid name for this ray. A key is provided to species of the genus.
Two Australian endemic elasmobranchs, the Argus skate Dipturus polyommata and the eastern spotted gummy shark Mustelus walkeri, were collected from the by-catch of a prawn Melicertus plebejus trawl fishery off Queensland. Age and growth parameters were estimated from growth band counts in vertebral sections of 220 D. polyommata and 44 M. walkeri. Dipturus polyommata males and females had an observed maximum age of 10 years and reached maximum sizes of 369 and 371 mm total length (LT), respectively. Mustelus walkeri lived longer, with the oldest female aged 16 years and measuring 1050 mm stretched total length (LST), and oldest male aged 9 years and 805 mm LST. Dipturus polyommata grew relatively fast with a von Bertalanffy growth completion parameter of k = 0·208 year−1 with males reaching maturity at 4·0 years (c. 278 mm LT) and females at 5·1 years (c. 305 mm LT). Mustelus walkeri grew more slowly with k = 0·033 year−1 with males estimated to mature at 7–9 years (670–805 mm LST) and females at 10–14 years (833–1012 mm LST). Length at birth inferred from neonate D. polyommata was 89–111 mm LT while for M. walkeri it was estimated to be 273 LST based on the value of L0 from the von Bertalanffy growth model. Both species appeared to have continuous reproductive cycles and low fecundity with an average ovarian fecundity of eight follicles for D. polyommata and a litter size of five to seven pups for M. walkeri. Based on these life-history traits, D. polyommata is more resilient to fishing pressure than M. walkeri.
Question - Please help me in identification of these Rays?
Hi Alireza, That image you attached looks like it is Urogymnus asperrimus. Has no tail spines and thorns over all of disc. closely related to H. granulata and should be in same genus
Question - Please help me in identification of these Rays?
top 3 are most likely Himantura granulata and bottom 2 images are Dasyatis microps
1. Manta and devil rays of the subfamily Mobulinae (mobulids) are rarely studied, large, pelagic elasmobranchs, with all eight of well-evaluated species listed on the IUCN Red List as threatened or near threatened. 2. Mobulids have life history characteristics (matrotrophic reproduction, extremely low fecundity, and delayed age of first reproduction) that make them exceptionally susceptible to overexploitation. 3. Targeted and bycatch mortality from fisheries is a globally important and increasing threat, and targeted fisheries are incentivized by the high value of the global trade in mobulid gill plates. 4. Fisheries bycatch of mobulids is substantial in tuna purse seine fisheries. 5. Thirteen fisheries in 12 countries specifically targeting mobulids, and 30 fisheries in 23 countries with mobulid bycatch were identified. 6. Aside from a few recently enacted national restrictions on capture, there is no comprehensive monitoring,
Oceanic whitetip sharks (Carcharhinus longimanus) in the Western Central Pacific have been overfished and require improved assessment and management to enable planning of recovery actions. Samples from 103 individuals (70 males and 33 females; 76.0-240- and 128-235-cm total length (TL) respectively) were used to estimate age, growth and maturity parameters from sharks retained by longline fisheries in Papua New Guinea. Back-calculation was used because of the low number of juveniles and a multimodel framework with Akaike's information criterion corrected for small sample size (AICc) estimated growth parameters. The von Bertalanffy growth model provided the best fitting growth model for both sexes. Parameter estimates for males were: Asymptotic length (L∞)≤315.6cm TL; growth coefficient (k)≤0.059 year-1; and length at birth (L0)≤75.1cm TL. For females, the parameter estimates were: L∞≤316.7cm TL; k≤0.057 year-1; and L0≤74.7cm TL. Maximum age was estimated to be 18 years for males and 17 years for females, with a calculated longevity of 24.6 and 24.9 years respectively. Males matured at 10.0 years and 193cm TL, whereas females matured at 15.8 years and 224cm TL. C. longimanus is a slow-growing, late-maturity species, with regional variation in life history parameters, highlighting increased vulnerability to fishing pressure in this region.
The bamboo sharks, genus Hemiscyllium, comprises a group of nine species mainly restricted to New Guinea and northern Australia, including islands, reefs, and shoals separated from mainland areas by shallow seas. The Indonesian island of Halmahera is the only location lying outside the core region that is inhabited by these sharks. The nine species in the genus are reviewed and their approximate distribution documented, as follows: H. freycineti (Raja Ampat Islands, West Papua); H. galei (Cenderawasih Bay, West Papua); H. hallstromi (Torres Strait, Australia and southeastern Papua New Guinea); H. halmahera (Halmahera, Indonesia); H. henryi (vicinity of Triton Bay, West Papua); H. michaeli (Milne Bay Province, Papua New Guinea); H. ocellatum (northeastern Queensland, Australia); H. strahani (central coast of northern New Guinea); and H. trispeculare (northwestern Australia and Aru Islands, Indonesia). The most reliable means of identification is color pattern, in combination with geographic distribution: morphology is less useful due to considerable morphological variation, mostly reflecting the highly variable condition of preserved specimens, and meristic comparisons are limited by mostly small sample sizes. Therefore, a key to species based on color pattern is presented, as well as comprehensive illustrative coverage for each species.
Limited information is available on artisanal and subsistence shark fisheries across the Pacific. The aim of this study was to investigate Fiji's inshore fisheries which catch sharks. In January and February 2013, 253 semi-directive interviews were conducted in 117 villages and at local harbours on Viti Levu, Vanua Levu, Taveuni, Ovalau and a number of islands of the Mamanuca and Yasawa archipelagos. Of the 253 interviewees, 81.4% reported to presently catch sharks, and 17.4% declared that they did not presently catch any sharks. Of the 206 fishers that reported to catch sharks, 18.4% targeted sharks and 81.6% caught sharks as bycatch. When targeted, primary use of sharks was for consumption or for sale. Sharks caught as bycatch were frequently released (69.6%), consumed (64.9%) or shared amongst the community (26.8%). Fishers' identification based on an identification poster and DNA barcoding revealed that at least 12 species of elasmobranchs, 11 shark and one ray species (Rhynchobatus australiae) were caught. This study, which is the first focused exploration of the shark catch in Fiji's inshore fisheries, suggests that the country's artisanal shark fisheries are small but have the potential to develop into larger and possibly more targeted fisheries.
For over a hundred years, the “river sharks” of the genus Glyphis were only known from the type specimens of species that had been collected in the 19th century. They were widely considered extinct until populations of Glyphis-like sharks were rediscovered in remote regions of Borneo and Northern Australia at the end of the 20th century. However, the genetic affinities between the newly discovered Glyphis-like populations and the poorly preserved, original museum-type specimens have never been established. Here, we present the first (to our knowledge) fully resolved, complete phylogeny of Glyphis that includes both archival-type specimens and modern material. We used a sensitive DNA hybridization capture method to obtain complete mitochondrial genomes from all of our samples and show that three of the five described river shark species are probably conspecific and widely distributed in Southeast Asia. Furthermore we show that there has been recent gene flow between locations that are separated by large oceanic expanses. Our data strongly suggest marine dispersal in these species, overturning the widely held notion that river sharks are restricted to freshwater. It seems that species in the genus Glyphis are euryhaline with an ecology similar to the bull shark, in which adult individuals live in the ocean while the young grow up in river habitats with reduced predation pressure. Finally, we discovered a previously unidentified species within the genus Glyphis that is deeply divergent from all other lineages, underscoring the current lack of knowledge about the biodiversity and ecology of these mysterious sharks.
Recent surveys of the shark and ray catches of artisanal fishers in the Western Province of Papua New Guinea (PNG) resulted in the rediscovery of the threatened river sharks, Glyphis garricki and Glyphis glyphis. These represent the first records of both species in PNG since the 1960s and 1970s and highlight the lack of studies of shark biodiversity in PNG. Two individuals of G. garricki and three individuals of G. glyphis were recorded from coastal marine waters of the Daru region of PNG in October and November 2014. The two G. garricki specimens were small individuals estimated to be 100–105 cm and ~113 cm total length (TL). The three G. glyphis specimens were all mature, one a pregnant female and two adult males. These are the first adults of G. glyphis recorded to date providing a more accurate maximum size for this species, i.e. ~260 cm TL. A single pup which was released from the pregnant female G. glyphis, was estimated to be ~65 cm TL. Anecdotal information from the fishers of pregnant females of G. glyphis containing 6 or 7 pups provides the first estimate of litter size for this species. The jaws of the pregnant female G. glyphis were retained and a detailed description of the dentition is provided, since adult dentition has not been previously documented for this species. Genetic analyses confirmed the two species cluster well within samples from these species collected in northern Australia.
Age and growth estimates from length‑at‑age data were produced for the common blacktip shark Carcharhinus limbatus from Indonesia. Back‑calculation techniques were used due to a low sample size (n = 30), which was dominated by large, mature sharks. A multi‑model approach incorporating Akaike's information criterion with a bias correction (AICc) was used to estimate growth rates, with the von Bertalanffy growth function (VBGF) providing the best fit for the separate sexes using the back‑calculation data. These age and growth estimates were then compared to those of other populations of C. limbatus from the USA and South Africa using a combination of VBGF parameters and instantaneous (empirical) growth rates at birth (dL/dt0) and maturity (dL/dtmat). In comparison with populations from the USA, C. limbatus from Indonesia grow substantially larger and are more similar to South African populations. Differences in empirical growth rates were also determined between the populations, although this was not detected by the VBGF parameter k. This occurred because the parameter k is a measure of the rate at which a population reaches asymptotic length (L∞) and is not a measure of growth. This study demonstrated that the use of dL/dt0 and dL/dtmat to measure and compare empirical growth rates can be a useful addition to life‑history studies.
A new species of eagle ray, Aetomylaeus caeruleofasciatus sp. nov., is described based on specimens collected in northern Australia and southern Papua New Guinea. The new species is very closely related to Aetomylaeus nichofii and was previously considered to be conspecific with this species. The new species and A. nichofii differ from their congeners in having a dorsal pattern of seven or eight transverse pale blue bands. As with other eagle ray species, morphological characteristics which distinguish the closely related species were largely obscured by intraspecific variation. The clearest morphological differences were apparent when comparing adult males to adult males and adult females to adult females, e.g. disc longer in adult female A. caeruleofasciatus compared to adult female A. nichofii. The two species also differ in the number of pelvic radials in both females and males and show subtle colour differences. A neotype is also allocated for A. nichofii.
This study used a network of acoustic receivers deployed around a no-take zone in Mangrove Bay, within the Ningaloo Reef Marine Park in Western Australia, to study residency and habitat preference of a small coastal shark, the nervous shark Carcharhinus cautus. Twelve C. cautus were tagged with acoustic tags and monitored for up to 579 days. Based on individuals detected within the receiver array for at least 2 months, C. cautus had small core (50% kernel utilization distribution, KUD) and home ranges (95% KUD) of 0·66 and 3·64 km(2) , respectively, and showed a strong habitat preference for mangroves, which are only found in the no-take zone. This resulted in C. cautus spending most of their detected time within the no-take zone boundaries (mean = 81·5%), showing that such a protected area could be beneficial to protect this species from extensive fishing pressure and local depletion, where required. Not all C. cautus remained within the acoustic array, however, suggesting that individual variations occur and that not all individuals would benefit from such protection. This study provides important information about the habitat, residency and movements of C. cautus that can be used for management and conservation. The strong affinity and residency of C. cautus within a mangrove-fringing coastline, emphasizes the importance of mangrove habitat to the species and suggests that such preferences can be used to design appropriate no-take zones for this species or others with similar habitat preferences. © 2015 The Fisheries Society of the British Isles.
- Jun 2015
Upeneus lombok n. sp. is described from two specimens collected off Lombok, Indonesia, at depths of 54-76 m, and one subadult specimen from the local fish market at Tanjung Luar, Lombok. Four specimens of U. asymmetricus were collected at the same fish market representing the first record of the species since its description from two Philippine Islands in 1954. These two species are compared in detail and with five congeneric species that all share a 7-spined dorsal fin and a high gill-raker count. Upeneus lombok n. sp. differs from all other congeners in having a short snout (snout length 9.0-9.6% SL) combined with a low anal fin (anal-fin height 12-13% SL in adults, 15% in single subadult). The newly recorded U. asymmetricus specimens differ from their types only slightly and all eight specimens together differ from all congeneric species in the combination of 7 dorsal spines, 12-14 pectoral fin rays, 26-28 total gill rakers, short pectoral fins (pectoral-fin length 18-21% SL) and short jaws (upper jaw length 8.7-11% SL). In both species the caudal-fin colour patterns of fresh fish are of diagnostic significance, the only exception being a close similarity between Upeneus lombok n.sp., U. saiab, and U. seychellensis. Additional comparisons with 14 Upeneus species which overlap in distribution or occur in nearby areas are also made. Needs for further taxonomic exploration of the Indonesian-Philippine region and for enhanced attention to the economic and ecological importance of Upeneus species are discussed.
The eagle rays Myliobatis hamlyni Ogilby, 1911 and Myliobatis tobijei Bleeker, 1854 are redescribed based on museum specimens and new material from Australia, Indonesia, the Philippines, Taiwan and Japan. These two species are closely related to Myliobatis aquila (L.) from the eastern Atlantic and can be distinguished from each other by a combination of their coloration, meristics, depth preferences and subtle morphometric characters. Myliobatis hamlyni was previously considered to be an Australian endemic, but its distribution is herein extended northward to Taiwan and Okinawa. Myliobatis tobijei was considered to occur southwards from Japan to Indonesia, but its distribution is herein restricted to the western North Pacific, primarily Japan.
- Apr 2015
A recent stranding of a basking shark Cetorhinus maximus in north-western Bali represents the first confirmed record of this large, filter-feeding shark species in Indonesian waters. Based on measurements of the fins and claspers, the adult male specimen was estimated to be between 5.6 and 8.1 m LT, with an average estimate of 6.7m LT. It is possible that the Indonesian Throughflow is an important route for this species during transequatorial migrations.
A new species of catshark of the genus Atelomycterus is described from eastern Indonesia based on two type specimens. Atelomycterus erdmanni is closely related to A. baliensis and A. marmoratus, being sympatric with the latter. It differs from these two species in coloration, external morphology, meristics and clasper morphology. Atelomycterus erdmanni differs from A. baliensis in having white spots present over the body (vs. white spots absent), a larger first dorsal fin, paired fins closer together, and pelvic fin farther apart from the ventral caudal-fin origin. It differs from A. marmoratus in having far less numerous white spotting, a larger first dorsal fin, and the clasper glans about half length of clasper outer margin (vs. less than half length of outer margin). Its status was also confirmed by genetic analysis with comparison of the mitochondrial cytochrome c oxidase subunit 1 (CO1) genetic marker utilised in DNA barcoding producing a genetic divergence of 4.8% and 5.3% between the new species and its closest congeners, A. baliensis and A. marmoratus, respectively.
Indonesia has the greatest reported chondrichthyan catches worldwide, with c.110,000 t caught annually. The pelagic thresher (Alopias pelagicus) and scalloped hammerhead (Sphryna lewini) together comprise about 25% of the total catches of sharks landed in Indonesia. Age and growth parameters were estimated for A. pelagicus and S. lewini from growth-band counts of thin-cut vertebral sections. Alopias pelagicus (n = 158) and S. lewini (n = 157) vertebrae were collected from three Indonesian fish markets over a 5 year period. A multi-model analysis was used to estimate growth parameters for both species. The models of best fit for males and females for A. pelagicus was the three-parameter logistic (L∞ = 3169 mm LT , k = 0·2) and the two-parameter von Bertalanffy models (L∞ = 3281 mm LT , k = 0·12). Age at maturity was calculated to be 10·4 and 13·2 years for males and females, respectively, and these are the oldest estimated for this species. The samples of S. lewini were heavily biased towards females, and the model of best fit for males and females was the three-parameter Gompertz (L∞ = 2598 mm LT , k = 0·15) and the two-parameter Gompertz (L∞ = 2896 mm LT , k= 0·16). Age at maturity was calculated to be 8·9 and 13·2 years for males and females, respectively. Although numerous age and growth studies have previously been undertaken on S. lewini, few studies have been able to obtain adequate samples from all components of the population because adult females, adult males and juveniles often reside in different areas. For the first time, sex bias in this study was towards sexually mature females, which are commonly lacking in previous biological studies on S. lewini. Additionally, some of the oldest aged specimens and highest age at maturity for both species were observed in this study. Both species exhibit slow rates of growth and late age at maturity, highlighting the need for a re-assessment of the relative resilience of these two globally threatened sharks at current high levels of fishing mortality throughout the eastern Indian Ocean. © 2014 The Fisheries Society of the British Isles.
The Gulf has a unique diversity of sharks and rays, but for many years their correct identification has been problematic. This fully illustrated book - the first of its kind to focus on the Gulf - brings together the latest research and years of work by the authors to provide a clear and comprehensive guidebook. For each species known to occur in the Gulf, colour images, identification features, and notes on distribution, abundance, ecology and conservation status are provided. Images and information are also provided on those species from nearby sea areas that might turn up in Gulf fish markets. Sharks & Rays of the Arabian/Persian Gulf will be of interest to all those with an interest in the Gulf's marine environment or in marine wildlife such as divers, anglers, natural history enthusiasts, conservationists, research biologists and government fisheries staff.
- Dec 2014
The biological aspects of members of the order Orectolobiformes exploited in Indonesian waters are given. Seven species belonging to five families were recorded in the catches at various landing sites in southern Indonesia. Of these, Chiloscyllium punctatum was the most abundant species landed, contributing >50% of the number of orectolobiforms recorded. The biological data obtained varied greatly between the species listed. The total length (LT ) at maturity for some species, e.g. C. punctatum and Nebrius ferrugineus, varied from that which has been previously recorded for those species in other regions. This highlights the need for regional-specific biological data for fisheries managers and conservation assessors. © 2014 The Fisheries Society of the British Isles.
Question - DId you find any evidence of sawfishes (Family: Pristidae) in this region?
No specific records from Brunei to my knowledge but Mabel Manjaji-Matsumoto and Annie Lim would probably be the best to ask
- Nov 2014
The highly diverse deepwater demersal ichthyofauna of the western Coral Sea was first systematically surveyed in two exploratory voyages in 1985 and 1986, and these fish assemblages have not been investigated at the same level since. Only recently have catch data and specimens, obtained from these first voyages almost 3 decades ago, been rigorously investigated and analysed. Some 393 species of fishes from 125 families were collected during the 1985 voyage which surveyed the northeastern Australian continental margin, and the Saumarez and Queensland Plateaus. A checklist of the species caught is provided. Levels of endemicity of deepwater fishes in the western Coral Sea are very high with about 50% of well-studied groups, such as sharks and rays, confined to this relatively small geographic region. A very high proportion of species caught during this voyage were either undescribed (78 species or 20%) or new Australian records (96 species or 24%) at the time of the survey. Another 68 species (17%) are the subject of further taxonomic investigation or are currently undergoing formal description. The fauna exhibits some intraregional differences in structure. Biogeographically informative fishes such as skates appear to be cryptically partitioned within the region, differing in composition to other Australian regions and those of French territories to the east. Strong depth-related partitioning of the fauna is also evident, and its structure follows zonation patterns observed across the wider Australian region. Given the high level of micro-endemicity and regional uniqueness of the fauna, there is a compelling argument for the existence of a faunal gyre in the Coral Sea. New gap-filling surveys are needed to better define the structure of this fauna and determine its distribution.
The somniosid species Scymnodon ichiharai Yano and Tanaka 1984 is redescribed based on the type specimens and additional material from Taiwan and Japan. The range of this species is extended to include Taiwanese waters. Although recently allocated to the genus Zameus, this species is very similar to Scymnodon plunketi from the southern Indo-West Pacific; our molecular evidence indicates that these species are sister-taxa. The genus Proscymnodon Fowler 1934 is placed in the synonymy of Scymnodon Barboza du Bocage and de Brito Capello 1864 and new generic definitions are provided for Scymnodon and the closely related Zameus. The genus Scymnodon is considered to include at least the species S. ichiharai, S. plunketi, and S. ringens; Proscymnodon macracanthus (Regan 1906) is allocated to Scymnodon, but its validity is uncertain. The genus Zameus is considered to be monotypic, containing only the species Z. squamulosus.
The complex multi-gear, multi-species tropical fisheries in developing countries are poorly understood and characterising the landings from these fisheries is often impossible using conventional approaches. A rapid assessment method for characterising landings at fish markets, using an index of abundance and estimated weight within taxonomic groups, is described. This approach was developed for contexts where there are no detailed data collection protocols, and where consistent data collection across a wide range of fisheries types and geographic areas is required, regardless of the size of the site and scale of the landings. This methodology, which was demonstrated at seven fish landing sites/fish markets in southern Indonesia between July 2008 and January 2011, provides a rapid assessment of the abundance and diversity in the wild catch over a wide variety of taxonomic groups. The approach has wider application for species-rich fisheries in developing countries where there is an urgent need for better data collection protocols, monitoring future changes in market demographics, and evaluating health of fisheries.
- Sep 2014
The generic arrangement of the eagle rays (Family Myliobatidae) is revised and the genus Pteromylaeus Garman, 1913 is placed into the synonymy of Aetomylaeus Garman, 1908. Definitions are provided for the three valid genera, Aetobatus, Aetomylaeus and Myliobatis, and nomenclatural issues are discussed. Aetobatus differs from the latter two genera in having: a deeply notched nasal curtain, both jaws with a single row of chevron-shaped teeth, broadly rounded pectoral-fin free rear tips, pectoral fins separate from rostral lobe and joining head at level of eye. Aetomylaeus differs from the other two genera in having: pectoral fins separate from rostral lobe and joining head below level of eye, and stinging spine absent or present (usually not well developed when present). Myliobatis differs from the other two genera in having the pectoral fins joined to the rostral lobe by a subocular ridge. A list of valid species is provided, including a list of junior synonyms. Myliobatis australis Macleay, 1881 from southern Australia is placed into the synonymy of the previously considered endemic New Zealand species, M. tenuicaudatus Hector, 1877.
- Jun 2014
A new species of whaler shark, Carcharhinus humani sp. nov., is described based on five type specimens from the western Indian Ocean near the Socotra Islands, off Kuwait, Mozambique, and South Africa. The new species represents the fifth species of the C. dussumieri/sealei group and the third species of the C. sealei subgroup. The new species is the only species of the C. sealei subgroup known from the western Indian Ocean. Within the C. sealei subgroup, C. humani differs from C. sealei in having a sharply demarcated black apical marking on the second dorsal fin which does not extend onto body surface (vs. black marking diffuse-edged and usually extending onto upper sides of trunk), a longer horizontal prenarial length (4.1–4.7 vs. 3.4–4.2% TL), and a longer preoral length (6.8–7.6 vs. 5.7–6.5% TL); C. humani differs from C. coatesi in having a taller second dorsal fin (its height 4.0–4.5 vs. 2.9–3.6% TL), a shorter first dorsal fin (its length 13.4–14.6 vs. 14.8–17.3% TL), and more vertebrae (total centra 152–167 vs. 134–147).
Question - Which aquariums would have breeding programs for sharks?
Okinawa Churaumi Aquarium - breeds numerous species, including manta rays
Question - Does DNA really help a taxonomy? Is morphology insufficient to define species?
An example where DNA can help is when dealing with animal parts - e.g. dried shark fins. DNA barcoding has been shown to be able to accurately distinguish 99% of samples of sharks and rays to species. When dealing with dried shark fins where morphology of fins is difficult, DNA barcoding provides a method for determining species composition which was previously lacking. So yes, in some cases DNA is very useful for taxonomy. It is a tool and like all tools it can be misused and a lot of people do/have misused this tool. But in the right hands it is a powerful tool which should not be ignored, but instead used in concert with classical taxonomic methods.
Question - Is there a future for traditional taxonomy?
I think the key word which some have used previously is that DNA barcoding is a tool. You can use a tool correctly and you can use it incorrectly. Will DNA barcoding take over traditional taxonomy? No, certainly not. Molecular tools cannot answer nomenclatural problems, or determine field based characters for identification. I consider myself a traditional taxonomist but I also work closely with geneticists and my belief is the way forward is good collaboration between these two fields. DNA barcoding is great at highlighting where potential species complex issues may lie, but they cannot solve them. The use of DNA barcodes alone to identify a taxon is in my opinion bad practice, but that is based on my personal taxonomy expertise (fish) so I cannot comment on the other organism .