The biology and ecology of carcharhiniform sharks in the Gulf of Papua prawn trawl fishery

The elasmobranch fauna of Papua New Guinea (PNG) and its interaction with fisheries has been poorly studied in the past. Fisheries generally adversely impact elasmobranchs due to their low productivity life histories. Without fishery and region specific data on elasmobranchs the impact on their populations cannot be fully understood and subsequent development of appropriate fisheries management and conservation measures cannot be achieved. The objectives of this thesis were to address some of these data gaps for the Gulf of Papua Prawn Fishery (GoPPF) in PNG through the assessment of biological and ecological parameters of species caught as bycatch and the development of an ecological risk assessment for all elasmobranch species caught in the fishery. The ecological component of this work focused on the feeding relationships among the Australian blackspot shark Carcharhinus coatesi, the milk shark Rhizoprionodon acutus and the Australian sharpnose shark Rhizoprionodon taylori. Rhizoprionodon acutus had a more specific diet compared to the other species, feeding almost exclusively on teleosts while C. coatesi and R. taylori had more diverse diets that had greater overlap. The limited sampling in this study did not fully characterise the diets of the three species, however, it does provide the first empirical evidence of trophic relationships between these sympatric sharks and their prey for the Gulf of Papua. The biology of R. taylori and C. coatesi was investigated through determination of their age, growth and maturity. Ages were determined from vertebrae samples. Length at age data were fitted to several models in a multi-model information theoretic approach to determine which model provided the best fit. Maturity was analysed using logistic regression of maturity categories recorded from samples combined with size and age data. These studies provide an understanding of the growth rate and pattern of each species and the length and age which males and females of each species reach reproductive maturity. To assess the biology of R. taylori, 186 samples were collected comprising 131 females (31-66 cm TL) and 55 males (31-53 cm TL). 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 (????∞= 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 (????∞ = 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 GoPPF. 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. Carcharhinus coatesi is a similar small bodied coastal shark to R. taylori but some differences were observed in its growth and maturity parameters. The von Bertalanffy growth model also fit the data best for C. coatesi; parameters were L0 = 40.6 cm ± 0.8, L∞ = 74.8 cm ± 2.1, k = 0.33 year1 ± 0.06. Length-at-maturity analysis indicated that males reach maturity at L50 = 66.3 cm (CI: 63.8, 71.4) and L95 = 71.6 (C1: 64.6, 74.2) cm while females matured at L50 = 71.4 cm (CI: 61.5, 72.01) and L95 = 72.5 cm (CI: 62.7, 74.0). Age-at-maturity estimates showed that both males (A50 = 5.1 years (CI: 4.6, 7.1), A95 = 6.4 years (CI: 5.1, 7.2) and females (A50 = 5.3 years (CI: 3.5, 8.7) and A95 = 7.4 (CI: 3.6, 8.8) years) reach maturity at about the same age, but in comparison to other small bodied carcharhinids, C coatesi has slower growth in early life stages and reaches maturity at a later age. This biological trait along with a small litter size indicates that the population of C. coatesi in the Gulf of Papua may be more susceptible to decline as a result of fishing. An Ecological Risk Assessment (ERA) was conducted to estimate the susceptibility of species caught in the fishery and the potential for a species to recover from population declines due to fishing if they occur. Of the 39 elasmobranch species encountered as bycatch in the fishery 10 were classified as being at low risk, 26 subjected to medium risk and 3 at high risk. The species at high risk were the Australian blackspot shark C. coatesi, the eyebrow wedgefish Rhynchobatus palpebratus and the blackspotted whipray Maculabatis astra. This is the first ERA conducted for this fishery. The findings provide fishery managers with information to implement an ecosystem-based approach to managing the fishery to reduce bycatch and improve the sustainability of the GoPPF. This thesis has provided new information on the diet, age, growth, maturity and the potential risk of species suffering population declines from being caught in the GoPPF. These outcomes have implications for fisheries management and conservation of species in PNG and the surrounding regions. The areas of study begin to address current data gaps for this fishery and also set the foundation for future work to improve fisheries management and protect the survival of species through conservation measures in PNG

RP-HPLC METHOD FOR SIMULTANEOUS ESTIMATION OF RITONAVIR, OMBITASVIR AND PARITAPREVIR IN TABLET DOSAGE FORMS AND THEIR STRESS DEGRADATION STUDIES

Objective: The objective of the present study was to develop and validate a novel reverse phase high performance liquid chromatographic (RP-HPLC) method, for simultaneous determination of ritonavir (RIT), ombitasvir (OMB) and paritaprevir (PAR) in bulk mixtures, and in tablets. Methods: Determination of the drugs ritonavir (RIT), ombitasvir (OMB), and paritaprevir (PAR), was carried out applying Hypersil BDS C18 column (250 mm X 4.6 mm i.e., 5 µm particle size), with photodiode array detector at λmax of 254 nm. The mobile phase applied for the current study composed of two solvents, i.e. A (0.01N % w/v potassium di-hydrogen orthophosphate buffer, pH 3.0 adjusted with dilute orthophosphoric acid) and B (acetonitrile). The mobile phase was pumped at a flow rate of 1.0 ml/min in the isocratic mode. The validation study with respect to specificity, linearity, precision, accuracy, and robustness, limit of detection (LOD) and limit of quantification (LOQ) was carried out employing the ICH guidelines. Results: Ritonavir, ombitasvir, and paritaprevir showed linearity of response between 12.5-75 μg/ml for ritonavir, 3.125-18.75 µg/ml for ombitasvir and 18.75–112.5 µg/ml for paritaprevir, with a correlation coefficient (R2) 0.999, 0.999,0.999 for RIT, OMB, and PAR respectively. The % recovery obtained was 99.82±0.14 % RIT, OMB 100.03±0.96 % and for 99.96±0.26 % PAR. The LOD and LOQ values for RIT, OMB, PAR were obtained to be 0.02, 0.019and0.02, µg/ml and 0.07, 0.06 and 0.07 µg/ml, respectively. The method also exhibits good robustness for different chromatographic conditions like wavelength, flow rate, mobile phase, and injection volume. Conclusion: The method was successfully employed, for the quantification of RIT, OMB, and PAR, in the quality control of in-house developed tablets, and can be applied for the industrial use

Dietary overlap of carcharhinid sharks in the Gulf of Papua

Assessing the feeding patterns of sharks provides insight into ecological interactions. Three coastal sharks are common by-catch in the Gulf of Papua prawn fishery in Papua New Guinea. The diets of Carcharhinus coatesi (n = 122), Rhizoprionodon acutus (n = 83) and Rhizoprionodon taylori (n = 177) were assessed using stomach content analysis. Teleosts, crustaceans and molluscs were the main prey. Percentage frequency of occurrence (%FO) and percentage frequency by number (%N) were computed to describe dietary compositions. Non-metric multidimensional scaling and Morisita Index determined the level of feeding overlap. Rhizoprionodon taylori was a generalist feeder having the broadest diet, R. acutus was the most selective feeder, preying predominantly on teleosts and C. coatesi consumed the greatest proportion of crustaceans that increased with size. The pairwise ANOSIM tests showed significant difference in dietary compositions of R. acutus and R. taylori (P = 0.1%, R = 0.318) and R. acutus and C. coatesi (P = 0.1%, R = 0.589), which indicate potential resource partitioning. Further work should aim to adequately characterise diets, improve prey identification and investigate spatial and temporal resource use patterns. Understanding ecological processes informs ecosystem approaches fisheries management

Elasmobranch bycatch in the demersal prawn trawl fishery in the Gulf of Papua, Papua New Guinea

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

Age, growth and maturity of oceanic whitetip shark (Carcharhinus longimanus) from Papua New Guinea

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 (AIC(c)) 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-infinity) = 315.6 cm TL; growth coefficient (k) = 0.059 year(-1); and length at birth (L-0) = 75.1 cm TL. For females, the parameter estimates were: L-infinity = 316.7 cm TL; k = 0.057 year(-1); and L-0 = 74.7 cm 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 193 cm TL, whereas females matured at 15.8 years and 224 cm 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

Elasmobranch bycatch in the demersal prawn trawl fishery in the Gulf of Papua, Papua New Guinea

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

Rediscovery of the Threatened River Sharks, Glyphis garricki and G. glyphis, in Papua New Guinea

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

Papua New Guinea: a potential refuge for threatened Indo–Pacific river sharks and sawfishes

The conservation of threatened elasmobranchs in tropical regions is challenging due to high local reliance on aquatic and marine resources. Due primarily to fishing pressure, river sharks (Glyphis) and sawfishes (Pristidae) have experienced large population declines in the Indo-Pacific. Papua New Guinea (PNG) may offer a refuge for these species, as human population density is low, and river shark and sawfish populations are thought to persist. However, few data are available on these species in PNG, and risk posed by small-scale fishers is poorly understood. This study observed elasmobranch catches in small-scale fisheries in riverine and coastal environments in the East Sepik (northern region), Gulf, and Western Provinces (southern region) of PNG. Surveys were conducted over a period of weeks to months in each region, during the dry season across seven field trips from 2017 to 2020. We observed a total of 783 elasmobranchs encompassing 38 species from 10 families. River sharks made up 29.4% of observations in the southern region, while sawfishes made up 14.8 and 20.3% in the northern and southern regions, respectively. River sharks were commonly caught by small-scale fishers in lower riverine environments in southern PNG, while sawfishes were generally less common and mainly observed through dried rostra. The primary threat to river shark and sawfish populations is their capture by small-scale fishers targeting teleosts for swim bladder. Persisting populations of river sharks and sawfishes indicate that PNG is the second known nation with viable populations of multiple species in the Indo-Pacific. However, populations are declining or at high risk of decline, and fisheries management and conservation are required to realize the potential of PNG as a long-term refuge

Phenomenology of Heavy Meson Chiral Lagrangians

The approximate symmetries of Quantum ChromoDynamics in the infinite heavy quark ($Q=c,b$) mass limit ($m_Q \to \infty$) and in the chiral limit for the light quarks ($m_q \to 0,\;q=\,u,\,d,\,s$) can be used together to build up an effective chiral lagrangian for heavy and light mesons describing strong interactions among effective meson fields as well as their couplings to electromagnetic and weak currents, including the relevant symmetry breaking terms. The effective theory includes heavy ($Q \bar q$) mesons of both negative and positive parity, light pseudoscalars, as well as light vector mesons. We summarize the estimates for the parameters entering the effective lagrangian and discuss in particular some phenomenologically important couplings, such as $g_{B^* B \pi}$. The hyperfine splitting of heavy mesons is discussed in detail. The effective lagrangian allows for the possibility to describe consistently weak couplings of heavy ($B,\, D$) to light ($\pi,\, \rho, \, K^*,\,$ etc.) mesons. The method has however its own limitations, due to the requirement that the light meson momenta should be small, and we discuss how such limitations can be circumvented through reasonable ansatz on the form factors. Flavour conserving (e. g. $B^* \to B\, \gamma$) and flavour changing (e. g. $B \to K^* \, \gamma$) radiative decays provide another field of applications of effective lagrangians; they are discussed together with their phenomenological implications. Finally we analyze effective lagrangians describing heavy charmonium- like ($\bar Q Q$) mesons and their strong and electromagnetic interactions. The role of approximate heavy quark symmetries for this case and the phenomenological tests of these models are also discussed.Comment: 92 pages, LaTeX, 17 figures, to appear in Physics Reports, page size shortened to fit american forma

Impact of opioid-free analgesia on pain severity and patient satisfaction after discharge from surgery: multispecialty, prospective cohort study in 25 countries

Background: Balancing opioid stewardship and the need for adequate analgesia following discharge after surgery is challenging. This study aimed to compare the outcomes for patients discharged with opioid versus opioid-free analgesia after common surgical procedures.Methods: This international, multicentre, prospective cohort study collected data from patients undergoing common acute and elective general surgical, urological, gynaecological, and orthopaedic procedures. The primary outcomes were patient-reported time in severe pain measured on a numerical analogue scale from 0 to 100% and patient-reported satisfaction with pain relief during the first week following discharge. Data were collected by in-hospital chart review and patient telephone interview 1 week after discharge.Results: The study recruited 4273 patients from 144 centres in 25 countries; 1311 patients (30.7%) were prescribed opioid analgesia at discharge. Patients reported being in severe pain for 10 (i.q.r. 1-30)% of the first week after discharge and rated satisfaction with analgesia as 90 (i.q.r. 80-100) of 100. After adjustment for confounders, opioid analgesia on discharge was independently associated with increased pain severity (risk ratio 1.52, 95% c.i. 1.31 to 1.76; P < 0.001) and re-presentation to healthcare providers owing to side-effects of medication (OR 2.38, 95% c.i. 1.36 to 4.17; P = 0.004), but not with satisfaction with analgesia (beta coefficient 0.92, 95% c.i. -1.52 to 3.36; P = 0.468) compared with opioid-free analgesia. Although opioid prescribing varied greatly between high-income and low- and middle-income countries, patient-reported outcomes did not.Conclusion: Opioid analgesia prescription on surgical discharge is associated with a higher risk of re-presentation owing to side-effects of medication and increased patient-reported pain, but not with changes in patient-reported satisfaction. Opioid-free discharge analgesia should be adopted routinely