Journal articles: 'Carcharhinus obscurus'

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Rogers, P. J., C. Huveneers, S. D. Goldsworthy, W. W. L. Cheung, G. K. Jones, J. G. Mitchell, and L. Seuront. "Population metrics and movement of two sympatric carcharhinids: a comparison of the vulnerability of pelagic sharks of the southern Australian gulfs and shelves." Marine and Freshwater Research 64, no. 1 (2013): 20. http://dx.doi.org/10.1071/mf11234.

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The dusky shark Carcharhinus obscurus and the bronze whaler Carcharhinus brachyurus are large-bodied, marine predators that inhabit coastal and shelf waters of southern Australia. C. obscurus is considered to be among the most vulnerable pelagic sharks to overexploitation. This study focussed on population metrics and movement patterns of these sympatric species. Litters from two pregnant C. brachyurus were examined; these comprised 20 and 24 embryos, respectively. Tagging data indicated that 75% of whaler sharks tagged in this region by recreational fishers were juveniles, and 58% of recaptures occurred within 50 km of the tagging locations. Fishery catch samples comprised 99% juvenile C. brachyurus and C. obscurus. Our findings suggested that semi-protected gulf waters represented ecologically significant habitats of juveniles. A fuzzy-logic model showed that in terms of relative vulnerability to fishing, C. brachyurus ranked in the mid to lower end of the spectrum, when compared with six sympatric pelagic shark species, including the white shark, Carcharodon carcharias. Our findings emphasised a need for improvement to management measures for these carcharhinids, which are likely to play a significant role in the functioning of the temperate gulf and shelf ecosystems.

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Hesse, Ryan D., Michael Roach, Emma N. Kerr, Bhavya Papudeshi, Laís F. O. Lima, Asha Z. Goodman, Lisa Hoopes, et al. "Phage Diving: An Exploration of the Carcharhinid Shark Epidermal Virome." Viruses 14, no. 9 (September 5, 2022): 1969. http://dx.doi.org/10.3390/v14091969.

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The epidermal microbiome is a critical element of marine organismal immunity, but the epidermal virome of marine organisms remains largely unexplored. The epidermis of sharks represents a unique viromic ecosystem. Sharks secrete a thin layer of mucus which harbors a diverse microbiome, while their hydrodynamic dermal denticles simultaneously repel environmental microbes. Here, we sampled the virome from the epidermis of three shark species in the family Carcharhinidae: the genetically and morphologically similar Carcharhinus obscurus (n = 6) and Carcharhinus galapagensis (n = 10) and the outgroup Galeocerdo cuvier (n = 15). Virome taxonomy was characterized using shotgun metagenomics and compared with a suite of multivariate analyses. All three sharks retain species-specific but highly similar epidermal viromes dominated by uncharacterized bacteriophages which vary slightly in proportional abundance within and among shark species. Intraspecific variation was lower among C. galapagensis than among C. obscurus and G. cuvier. Using both the annotated and unannotated reads, we were able to determine that the Carcharhinus galapagensis viromes were more similar to that of G. cuvier than they were to that of C. obscurus, suggesting that behavioral niche may be a more prominent driver of virome than host phylogeny.

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Simpfendorfer, Colin A., Adrian Goodreid, and Rory B. McAuley. "Diet of three commercially important shark species from Western Australian waters." Marine and Freshwater Research 52, no. 7 (2001): 975. http://dx.doi.org/10.1071/mf01017.

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The diets of dusky (Carcharhinus obscurus), whiskery (Furgaleus macki) and gummy (Mustelus antarcticus) sharks from south-western Western Australia were examined by analysis of stomach contents. The majority of samples were obtained from catches of commercial gill-net fishers. Carcharhinus obscurus had a diverse diet dominated by pelagic teleosts and cephalopods. A wide range of demersal and benthic prey were also consumed, but represented only a small portion of the diet. As body size increased, importance of elasmobranchs in the diet of C. obscurus increased, while most other groups remained at similar levels. Furgaleus macki had a specialized diet, feeding almost exclusively on octopus and other cephalopods. The diet of M. antarcticus was dominated by benthic and epibenthic prey, including crabs, lobsters, tetraodontid fishes and octopus. As M. antarcticus increased in size there was an increase in the occurrence of rock lobster and a decrease in the occurrence of crabs in the diet. Differences in the diet were also noted between male and female M. antarcticus, but were confounded with differences between size classes.

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Rahayu, Slamet Mardiyanto. "IDENTIFIKASI IKAN DI PELABUHAN PERIKANAN TANJUNG LUAR, PULAU LOMBOK, PROVINSI NUSA TENGGARA BARAT." Jurnal Harpodon Borneo 13, no. 1 (November 25, 2020): 30–38. http://dx.doi.org/10.35334/harpodon.v13i1.1405.

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Sumberdaya ikan adalah jenis ikan termasuk biota perairan laut lainnya yang merupakan sumber kekayaan alam yang memiliki daya pulih kembali secara alami, sehingga pemanfaatannya dapat dilakukan secara berkelanjutan. Pelabuhan perikanan merupakan tempat pendaratan hasil tangkapan dan awal pemasarannya. jenis ikan hasil tangkapan nelayan yang didaratkan di Pelabuhan Perikanan Pantai Tanjung Luar, Kabupaten Lombok Timur. Penelitian dilakukan dengan metode survey dan identifikasi. Berdasarkan penelitian diperoleh sebanyak 34 jenis ikan hasil tangkapan nelayan di Pelabuhan Perikanan Tanjung Luar, Pulau Lombok, yaitu: Naso brevisrostris, Chanos chanos, Parastromateus niger, Thallasoma purpureum, Siganus canaliculatus, Plectorhinchus polytaenia, Diodon holocanthus, Upeneus vittatus, Caesio cuning, Dermogenys sp, Epinephelus areolatus, Rastrelliger sp, Pomadasys argenteus, Lepturacanthus savala, Decapterus macrosoma, Sillago sihama, Eusphyra blochii, Carcharhinus brevipinna, Carcharhinus albimarginatus, Carcharhinus limbatus, Carcharhinus obscurus, Galeocerdo cuvier, Prionace glauca, Taeniura lymma, Priancanthus hamrur, Scolopsis sp, Scombermorus guttatus, Euthynnus affinis, Nemipterus japonicas, Sardinella sp, Lutjanus bitaeniatus, Secutor interruptus, Sphyraena jello, dan Caranx ignobilis

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Braccini, Matias, Brett Molony, and Nick Blay. "Patterns in abundance and size of sharks in northwestern Australia: cause for optimism." ICES Journal of Marine Science 77, no. 1 (October 10, 2019): 72–82. http://dx.doi.org/10.1093/icesjms/fsz187.

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Abstract Reliable information for population assessments is rare for sharks. We quantified patterns in catch rates and mean size for numerous tropical and subtropical species from 15 years of fishery-independent surveys (2002–2017) in northwestern Australia. This study region represents an area of ~0.8 million km2 which was closed to commercial shark fishing from 1993 or 2005 onward due to the very high State-wide catches of sandbar (Carcharhinus plumbeus) and dusky (Carcharhinus obscurus) sharks. A total of 43 shark and ray species were sampled, with sandbar shark being the most commonly caught species, followed by milk (Rhizoprionodon acutus), spot-tail (Carcharhinus sorrah), tiger (Galeocerdo cuvier), blacktip (Carcharhinus limbatus and Carcharhinus tilstoni), dusky and sliteye (Loxodon macrorhinus) sharks, and scalloped hammerhead (Sphyrna lewini). For sandbar shark, catch rates increased between 2008 and 2017 whereas for other taxa catch rates were mostly stable (albeit fluctuating). Mean size at capture fluctuated across years with no particular trends. Unlike for other parts of the world, catch rates and mean size of northwestern Australian sharks have been stable or increased in recent years. Though most shark species have conservative life histories, when science, management and enforcement work synergistically, sustainable resource use, recovery and conservation outcomes can all be achieved.

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Bornatowski, Hugo, Andrés Felipe Navia, Raul Rennó Braga, Vinícius Abilhoa, and Marco Fábio Maia Corrêa. "Ecological importance of sharks and rays in a structural foodweb analysis in southern Brazil." ICES Journal of Marine Science 71, no. 7 (March 5, 2014): 1586–92. http://dx.doi.org/10.1093/icesjms/fsu025.

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Abstract Understanding the trophic interactions and the position of species within a foodweb is crucial if we want to understand the dynamics of marine communities and the impact individual components of the community have on trophic network compartments. Recent studies have indicated sharks and rays are important elements within foodwebs. In this study, we evaluated the ecological importance of sharks and rays in a subtropical ecosystem off the coast of southern Brazil by using topological analyses. We tested the hypotheses that some elasmobranchs can be considered key elements within the foodweb, and that large predators have topological importance (act as keystones), so that, when large predators are excluded, mesopredator elasmobranchs occupy higher topological positions. Our results indicate that Galeocerdo cuvier, Carcharhinus obscurus, Carcharias taurus, Sphyrna lewini and S. zygaena are species with large ecological function values and may exert a powerful influence over lower levels. These issues need to be considered by conservation and fishery management groups since it appears that ecosystem integrity may be compromised by reductions in the populations of large predators. Carcharhinus obscurus, S. zygaena and Zapteryx brevirostris were found to be the elasmobranchs with largest values of centrality, and can, therefore, be considered key elements in the topological structure.

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Braccini, Matias, Simon de Lestang, and Rory McAuley. "Dusky sharks (Carcharhinus obscurus) undertake large-scale migrations between tropical and temperate ecosystems." Canadian Journal of Fisheries and Aquatic Sciences 75, no. 9 (September 2018): 1525–33. http://dx.doi.org/10.1139/cjfas-2017-0313.

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Understanding the large-scale migrations of marine predators can allow better representation of their population dynamics. The migration biology of dusky sharks (Carcharhinus obscurus), a cosmopolitan large marine predator with very low resilience to fishing, was quantified using a large-scale network of acoustic receivers deployed across Western Australia. Time-series plotting of individual shark detections and modified logistic modelling were used to determine the timing of acoustically tagged sharks’ seasonal migration, the proportion of the population migrating, and the size at which sharks start to migrate. Large (>200 cm fork length) dusky sharks migrated between areas closed (north) and open (south) to commercial shark fishing. There was limited evidence that smaller sharks occurred in the northern study area, whereas several larger individuals of both sexes undertook repeated north–south displacements, moving between disparate ecosystems within the Indian Ocean (21.7°S–35.4°S) and covering round-trip distances of 2000–3000 km per migratory event. For migrating individuals, the probability of occurring in the north was high in the austral winter–spring and low (males) to moderate (females) during the austral summer–autumn.

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Pank, Melissa, Michael Stanhope, Lisa Natanson, Nancy Kohler, and Mahmood Shivji. "Rapid and Simultaneous Identification of Body Parts from the Morphologically Similar Sharks Carcharhinus obscurus and Carcharhinus plumbeus (Carcharhinidae) Using Multiplex PCR." Marine Biotechnology 3, no. 3 (May 1, 2001): 231–40. http://dx.doi.org/10.1007/s101260000071.

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Dudley, Sheldon F. J., and Colin A. Simpfendorfer. "Population status of 14 shark species caught in the protective gillnets off KwaZulu - Natal beaches, South Africa, 1978 - 2003." Marine and Freshwater Research 57, no. 2 (2006): 225. http://dx.doi.org/10.1071/mf05156.

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Shark nets have been set off the beaches of KwaZulu–Natal, South Africa, since 1952 to reduce the risk of shark attack. The nets fish in fixed localities 400 m from shore and both directly affect local shark populations and act as fisheries-independent monitoring devices. Reliable catch information at the species level was available for the period 1978–2003. Trends in catch rate and size were used to assess the population status of 14 commonly caught shark species. In addition, a demographic modelling approach was used in conjunction with the catch information to assess the potential effect of the nets on populations. Catch rates of four species (Carcharhinus leucas, C. limbatus, Sphyrna lewini and S. mokarran) showed a significant decline, as did the mean or median length of three species (Carcharhinus amboinensis, C. limbatus and female Carcharodon carcharias). For three species that showed declining catch rates or length the potential effect of the shark nets was assessed to be low, suggesting that other sources of catch were responsible for the declining status. The potential effect of the shark nets was assessed to be high for two species (Carcharhinus obscurus and Carcharias taurus, neither of which showed declines in catch rate or length), because of very low intrinsic rates of population increase.

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Hussey, Nigel E., Sheldon F. J. Dudley, Ian D. McCarthy, Geremy Cliff, and Aaron T. Fisk. "Stable isotope profiles of large marine predators: viable indicators of trophic position, diet, and movement in sharks?" Canadian Journal of Fisheries and Aquatic Sciences 68, no. 12 (December 2011): 2029–45. http://dx.doi.org/10.1139/f2011-115.

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Understanding the role of predators is challenging but critical for ecosystem management. For community dynamics, predator-specific size-based variation in diet, trophic position, and habitat use are rarely accounted for. Using two applied tools (stable isotopes and stomach content data), we examined inter- and intra-species ontogenetic variability in diet (stomach contents), trophic position (TPSIA for δ15N and TPSCA for stomach contents), and habitat use (δ13C) of two large sharks, the scalloped hammerhead ( Sphyrna lewini ) and the dusky ( Carcharhinus obscurus ). Stomach contents identified size-based and gender-specific shifts in diet indicating resource partitioning for and between species. Calculated TP for the two sharks varied by method, either TPSIA or TPSCA and with species, size, and gender, but were complicated by differing baselines and broad functional prey groups, respectively. TP increased with size for S. lewini, but was low in large C. obscurus compared with small sharks. Size-based δ13C profiles indicated habitat partitioning by sex in S. lewini and a movement to shelf edge foraging in large C. obscurus. These results demonstrate that predators exert proportional size-based effects on multiple components of the marine system that are further complicated by species- and gender-specific strategies.

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Hussey, NE, DT Cocks, SFJ Dudley, ID McCarthy, and SP Wintner. "The condition conundrum: application of multiple condition indices to the dusky shark Carcharhinus obscurus." Marine Ecology Progress Series 380 (April 7, 2009): 199–212. http://dx.doi.org/10.3354/meps07918.

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Dicken, M. L., A. A. Kock, and M. Hardenberg. "First observations of dusky sharks (Carcharhinus obscurus) attacking a humpback whale (Megaptera novaeangliae) calf." Marine and Freshwater Research 66, no. 12 (2015): 1211. http://dx.doi.org/10.1071/mf14317.

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Direct observations of sharks attacking mysticetes are rare. The present study provides the first direct observation of dusky sharks (Carcharhinus obscurus) attacking a humpback whale (Megaptera novaeangliae) calf. The event was witnessed on 16 July 2014 within the Pondoland Marine Protected Area, South Africa, during the annual sardine run. The event involved a group of ~10 to 20 dusky sharks ranging in length between 2 and 3m. The sharks followed in a loose group behind the whale and attacked it while it was on the surface as well as when diving. Shark bites were concentrated on the left-hand side of the whale’s body primarily between the pectoral fin and tail fluke, with almost no bites on the right-hand side. Most of the bites were superficial and resulted in tooth impressions and scrapes with little tissue removed. The condition of the calf deteriorated over the study period and it was presumed to have drowned from exhaustion when it stopped surfacing. These observations provide a new insight into the potential threat that dusky sharks may pose to whale calves.

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Pirog, Agathe, Antonin Blaison, Sébastien Jaquemet, Marc Soria, and Hélène Magalon. "Isolation and characterization of 20 microsatellite markers from Carcharhinus leucas (bull shark) and cross-amplification in Galeocerdo cuvier (tiger shark), Carcharhinus obscurus (dusky shark) and Carcharhinus plumbeus (sandbar shark)." Conservation Genetics Resources 7, no. 1 (September 7, 2014): 121–24. http://dx.doi.org/10.1007/s12686-014-0308-3.

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Hussey, Nigel E., Ian D. McCarthy, Sheldon F. J. Dudley, and Bruce Q. Mann. "Nursery grounds, movement patterns and growth rates of dusky sharks, Carcharhinus obscurus: a long-term tag and release study in South African waters." Marine and Freshwater Research 60, no. 6 (2009): 571. http://dx.doi.org/10.1071/mf08280.

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Knowledge of movement patterns of sharks in coastal waters is critical for the structuring of regional management plans. Through a long-term tag–recapture program, 9716 dusky sharks (Carcharhinus obscurus) were tagged and released along the east coast of South Africa. A total of 648 C. obscurus, principally small sharks (<100 cm PCL), were recaptured. Most recaptures were within 100 km of the tagging location in the nursery habitat in KwaZulu-Natal (KZN) with small scale movements occurring throughout the year. Forty-eight C. obscurus undertook movements >200 km that indicated a southerly migration between KZN and Eastern/Southern Cape (E/SC) between June and November. Seasonal northerly migrations were less well defined. The largest southerly and northerly movements were 1323 km and 1374 km, respectively. For sharks moving 1–100 km south from their tagging locality in KZN, an increase in displacement occurred between June and September identifying animals beginning their migration to the E/SC. With increasing displacement, there was also an increase in minimum swimming speed. Calculated growth rates of small sharks of 10.3–11.5 cm year–1 were in agreement with current literature values. Established tag–recapture programs provide an important tool in understanding the ecology of early life-stages of coastal shark species.

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Joung, Shoou-Jeng, Jun-Hsu Chen, Chien-Pang Chin, and Kwang-Ming Liu. "Age and Growth of the Dusky Shark, Carcharhinus obscurus, in the Western North Pacific Ocean." Terrestrial, Atmospheric and Oceanic Sciences 26, no. 2-1 (2015): 153. http://dx.doi.org/10.3319/tao.2014.10.15.01(oc).

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Blower, D. C., S. Corley, J. P. Hereward, C. R. Riginos, and J. R. Ovenden. "Characterisation and cross-amplification of 21 novel microsatellite loci for the dusky shark, Carcharhinus obscurus." Conservation Genetics Resources 7, no. 4 (October 22, 2015): 909–12. http://dx.doi.org/10.1007/s12686-015-0499-2.

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Rossouw, C., S. P. Wintner, and A. E. Bester-Van Der Merwe. "Assessing multiple paternity in three commercially exploited shark species: Mustelus mustelus , Carcharhinus obscurus and Sphyrna lewini." Journal of Fish Biology 89, no. 2 (May 29, 2016): 1125–41. http://dx.doi.org/10.1111/jfb.12996.

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Hoffmayer, Eric R., James S. Franks, William B. Driggers, Jennifer A. McKinney, Jill M. Hendon, and Joseph M. Quattro. "Habitat, movements and environmental preferences of dusky sharks, Carcharhinus obscurus, in the northern Gulf of Mexico." Marine Biology 161, no. 4 (January 30, 2014): 911–24. http://dx.doi.org/10.1007/s00227-014-2391-0.

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Sulikowski, James A., Walt Golet, Eric R. Hoffmayer, William B. Driggers, Lisa J. Natanson, Amy Carlson, and Brett B. Sweezey. "Observing post-release mortality for dusky sharks, Carcharhinus obscurus, captured in the U.S. pelagic longline fishery." Fisheries Research 221 (January 2020): 105341. http://dx.doi.org/10.1016/j.fishres.2019.105341.

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Natanson, Lisa J., Gregory B. Skomal, Sarah L. Hoffmann, Marianne E. Porter, Kenneth J. Goldman, and David Serra. "Age and growth of sharks: do vertebral band pairs record age?" Marine and Freshwater Research 69, no. 9 (2018): 1440. http://dx.doi.org/10.1071/mf17279.

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Inaccurate age estimates can have severe consequences in the management of elasmobranchs. Numerous studies in shark age validation have demonstrated a disconnect between band pair counts and age, resulting in age underestimation, particularly in older individuals. To investigate the relationship between band pairs, vertebral shape and growth, we quantified intracolumn differences in centrum morphology (size and structure) and band pair counts in seven shark species: Squatina dumeril, Carcharodon carcharias, Lamna nasus, Isurus oxyrinchus, Alopias vulpinus, Prionace glauca and Carcharhinus obscurus. In all species examined, band pair deposition was closely related to body girth and the structural properties of the cartilaginous skeleton, relative to maximum size, and body type. These results have strong implications for accurately assessing age for fisheries management of these species.

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Drew, Michael, Paul Rogers, and Charlie Huveneers. "Slow life-history traits of a neritic predator, the bronze whaler (Carcharhinus brachyurus)." Marine and Freshwater Research 68, no. 3 (2017): 461. http://dx.doi.org/10.1071/mf15399.

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Intra-species plasticity in the life-history characteristics of sharks leads to the need for regional estimates to accurately determine resilience to anthropogenic effects. The present study provides the first length-at-age, growth and maturity estimates for the bronze whaler (Carcharhinus brachyurus) from southern Australia. Age estimates were obtained from vertebral sections of 466 individuals spanning 50–308-cm total length. Maximum estimates of age for males and females were 25 and 31 years respectively. The three-parameter logistic model for females (L∞=308cm LT, k=0.15, α=742) and for males (L∞=317cm LT, k=0.13, α=782) provided the best fit to the size at age data. Males matured at a similar age (16 years), but smaller size than females (224v. 270cm LT). Growth parameters and age-at-maturity estimates were similar to those for genetically isolated C. brachyurus populations, and the sympatric dusky shark (C. obscurus). The southern Australian C. brachyurus population is long-lived, slow growing and late maturing. These growth parameters are needed to undertake demographic analyses to assess the resilience of C. brachyurus to fishing, and provide an example of a wide-ranging elasmobranch with similar life-history characteristics across isolated populations.

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Simpfendorfer, Colin A., and Philip Unsworth. "Gill-net mesh selectivity of dusky sharks (Carcharhinus obscurus) and whiskery sharks (Furgaleus macki) from south-western Australia." Marine and Freshwater Research 49, no. 7 (1998): 713. http://dx.doi.org/10.1071/mf98004.

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Gill-net mesh selectivity parameters were estimated for C. obscurus and F. macki from catches of an experimental net composed of seven panels of mesh ranging in size from 12.7 cm to 21.6 cm. A maximum-likelihood model was used to fit a gamma distribution to length data from each of the different-sized meshes. Mesh selectivity parameters for the gilled-only data set were θ1 =126.90 and θ1 =20253, and for the data set including gilled and non-gilled sharks θ1 =130.13 and θ1 =29237. The advantages of the parameters from each of these data sets are discussed. Mesh-selectivity parameters for F. macki were θ1 =173.70 and θ2 =26415. The exclusion of data from the two largest mesh sizes, which had much lower catch rates than the other mesh sizes, did not significantly change the parameter estim- ates. Catch rates from the panels in the experimental net that correspond to those used by the commercial gill-net fishery in south-western Australia were compared and no significant differences were found.

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Maduna, Simo N., Charné Rossouw, Ruhan Slabbert, Sabine P. Wintner, Charlene da Silva, and Aletta E. Bester-van der Merwe. "New polymorphic microsatellite loci revealed for the dusky shark Carcharhinus obscurus through Ion Proton double-digest RAD sequencing." Molecular Biology Reports 45, no. 6 (September 14, 2018): 2759–63. http://dx.doi.org/10.1007/s11033-018-4338-x.

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Benavides, MT, RL Horn, KA Feldheim, MS Shivji, SC Clarke, S. Wintner, L. Natanson, et al. "Global phylogeography of the dusky shark Carcharhinus obscurus: implications for fisheries management and monitoring the shark fin trade." Endangered Species Research 14, no. 1 (April 7, 2011): 13–22. http://dx.doi.org/10.3354/esr00337.

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Geraghty, Pascal T., William G. Macbeth, and Jane E. Williamson. "Aspects of the reproductive biology of dusky, spinner and sandbar sharks (Family Carcharhinidae) from the Tasman Sea." Marine and Freshwater Research 67, no. 4 (2016): 513. http://dx.doi.org/10.1071/mf14228.

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Increased harvest pressure exerted on sharks worldwide has created a necessity for more information concerning the basic biology of targeted species. This study marks the first dedicated assessment of the reproductive biology of Carcharhinus obscurus, C. brevipinna and C. plumbeus in eastern Australian waters, where these species support a demersal longline fishery. We found all three to be late maturing species of low reproductive output, suggestive of an overarching susceptibility to stock depletion in the region. Length- (L50, cm LT) and age-at-maturity (A50, years), for females and males were respectively 281.1 and 15.5, and 271.9 and 14.6 for C. obscurus; 224.9 and 10.1, and 208.9 and 8.5 for C. brevipinna; and, 174.8 and 9.5, and 164.5 and 7.0 for C. plumbeus. Uterine fecundity (i.e. litter size) was observed at 5–12 (=9.6), 5–14 (=10.6) and 3–12 (=7.8) for the same three species respectively, and increased significantly with maternal length in C. brevipinna. Length-at-birth (L0, cm LT) ranged from 92 to 96 for C. obscurus, 79–82 for C. brevipinna and 66–76 for C. plumbeus, and all three species exhibited lengthy gestation periods, overall embryonic sex ratios of 1:1 and synchronous parturition in autumn. However, given limitations with respect to sample size and temporal distribution inherent in this study, the reproductive parameters defined herein are necessarily preliminary. Nevertheless, this research challenges a range of findings emanating from other parts of the world and, in doing so, raises pertinent questions relating to the resilience to targeted fishing activities of these species in New South Wales waters compared to other oceanic regions. Moreover, it reinforces the importance of locally derived demographic parameters for population modelling and stock assessment.

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Marshall, Heather, Gregory Skomal, Paige G. Ross, and Diego Bernal. "At-vessel and post-release mortality of the dusky (Carcharhinus obscurus) and sandbar (C. plumbeus) sharks after longline capture." Fisheries Research 172 (December 2015): 373–84. http://dx.doi.org/10.1016/j.fishres.2015.07.011.

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Wirtz, Peter, Jane Bingeman, John Bingeman, Ronald Fricke, Timothy J. Hook, and Jimmy Young. "The fishes of Ascension Island, central Atlantic Ocean – new records and an annotated checklist." Journal of the Marine Biological Association of the United Kingdom 97, no. 4 (September 23, 2014): 783–98. http://dx.doi.org/10.1017/s0025315414001301.

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A checklist of the fishes of Ascension Island is presented. The speciesRhincodon typus,Alopias superciliosus,Isurus oxyrinchus,Carcharhinus obscurus,Galeocerdo cuvier,Sphyrna lewini,Hexanchus griseus,Manta birostris,Gymnothorax vicinus,Hippocampussp.,Epinephelus itajara,Cookeolus japonicus,Apogon pseudomaculatus,Phaeoptyx pigmentaria,Remora albescens,Caranx bartholomaei,Carangoides ruber,Decapterus tabl,Seriola dumerili,Thalassoma sanctaehelenae,Cryptotomussp.,Ruvettus pretiosus,Acanthocybium solandri,Auxis rochei,Auxis thazard,Euthynnus alletteratus,Katsuwonus pelamis,Thunnus alalunga,Thunnus obesus,Xiphias gladius,Istiophorus platypterus,Kajikia albida,Makaira nigricans,Tetrapturus pfluegeri,Hyperoglyphe perciformis,Schedophilussp.,Cantherhines macrocerus,Sphoeroides pachygasterandDiodon eydouxiiare recorded for the first time from Ascension Island. We have recognized two previous records as identification errors and indicate 11 other records as doubtful. Including the 40 new records, we now list 173 fish species from Ascension Island, of which 133 might be considered ‘coastal fish species’. Eleven of these (8.3%) appear to be endemic to the island and a further 16 species (12%) appear to be shared endemics with St Helena Island.

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Romine, Jason G., John A. Musick, and George H. Burgess. "Demographic analyses of the dusky shark, Carcharhinus obscurus, in the Northwest Atlantic incorporating hooking mortality estimates and revised reproductive parameters." Environmental Biology of Fishes 84, no. 3 (January 31, 2009): 277–89. http://dx.doi.org/10.1007/s10641-008-9435-6.

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Natanson, Lisa J., Brian J. Gervelis, Megan V. Winton, Li Ling Hamady, Simon J. B. Gulak, and John K. Carlson. "Validated age and growth estimates for Carcharhinus obscurus in the northwestern Atlantic Ocean, with pre- and post management growth comparisons." Environmental Biology of Fishes 97, no. 8 (November 19, 2013): 881–96. http://dx.doi.org/10.1007/s10641-013-0189-4.

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McAuley, Rory B., Colin A. Simpfendorfer, and Norm G. Hall. "A method for evaluating the impacts of fishing mortality and stochastic influences on the demography of two long-lived shark stocks." ICES Journal of Marine Science 64, no. 9 (September 20, 2007): 1710–22. http://dx.doi.org/10.1093/icesjms/fsm146.

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Abstract McAuley, R. B., Simpfendorfer, C. A., and Hall, N. G. 2007. A method for evaluating the impacts of fishing mortality and stochastic influences on the demography of two long-lived shark stocks. — ICES Journal of Marine Science, 64. Stochastic demographic models were developed for Carcharhinus obscurus and C. plumbeus populations off the west coast of Australia by resampling the input parameters for life tables from empirical biological data collected from commercial target fisheries and fishery-independent surveys. The models were used to examine the effects of multiple scenarios of age-specific survival, derived from the fishing mortality rates estimated from a tagging study on sharks and indirect estimates of natural mortality. In the absence of fishing, median estimates of the rates of intrinsic population increase (r) were 0.025 for both species. Inclusion of the age-specific fishing mortality rates estimated for C. obscurus recruits born in 1994 and 1995 resulted in the median estimates of r declining to 0.007 and 0.012, respectively, suggesting that recent harvest levels of mainly neonates by the target fishery were probably sustainable. However, the model also suggested that the population was more susceptible to exploitation of older sharks than was previously believed. The C. plumbeus model indicated that fishing mortality between 2001 and 2004 was probably unsustainable. The increasingly negative trend in median r estimates (from –0.032 to –0.049), and the population’s apparently limited capacity for density-dependent compensation through changes in fecundity, somatic growth and longevity, suggests that management intervention is necessary to prevent continued stock depletion.

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Liu, Kwang-Ming, Lung-Hsin Huang, and Kuan-Yu Su. "Assessment of the Impact on 20 Pelagic Fish Species by the Taiwanese Small-Scale Longline Fishery in the Western North Pacific Using Ecological Risk Assessment." Animals 12, no. 16 (August 19, 2022): 2124. http://dx.doi.org/10.3390/ani12162124.

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Ecological risk assessment (ERA) has been applied on assessing the relative risk of bycatch species in recent years. ERA index is calculated by productivity of species and susceptibility of fisheries on fish species. In this study, a semi-quantitative method was used to evaluate the risks of exploitation for 20 pelagic fish species by the small-scale longline fisheries in the western North Pacific Ocean. The productivity was estimated based on the ranking (high, median, and low) of seven life history parameters. The susceptibility was calculated by the multiplication of the catchability, selectivity and post-capture mortality. The ERA results indicated the risks of sharks are higher than those of tunas and billfishes, except yellowfin tuna (Thunnus albacares). The shortfin mako shark (Isurus oxyrinchus) and dusky shark (Carcharhinus obscurus) have the highest risk. Other shark species, yellowfin tuna, and sailfish (Istiophorus platypterus) have medium risk. While the striped marlin (Kajikia audax), and albacore tuna (T. alalunga) have the lowest risk. Stock assessment and rigorous management measures such as catch quota and size limit are recommended for the species in high or medium ecological risk and a consistent monitoring management scheme is suggested for those in low ecological risk.

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Wintner, Sabine P., and Sven E. Kerwath. "Cold fins, murky waters and the moon: what affects shark catches in the bather-protection program of KwaZulu–Natal, South Africa?" Marine and Freshwater Research 69, no. 1 (2018): 167. http://dx.doi.org/10.1071/mf17126.

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The influence of environmental variables on shark catch in the bather-protection program along the eastern coast of South African was investigated for 11 commonly caught species (Carcharhinus limbatus, C. obscurus, C. brachyurus, C. plumbeus, C. brevipinna, C. leucas, Carcharodon carcharias, Carcharias taurus, Sphyrna lewini, S. zygaena, Galeocerdo cuvier). Data for the period 1986–1994 were analysed using generalised additive models and generalised additive mixed models. The influence of temporal and spatial factors was respectively considered and removed within a standardisation procedure to investigate and predict the influence of lunar cycle, sea-surface temperature (SST) and water visibility on daily catch. The catches of C. taurus and C. brevipinna were significantly affected by all three factors. Catches of all other species were affected by at least one of the three factors, e.g. six were affected by lunar phase, six by SST and seven by water visibility. The results suggested that measurable, predictable relationships exist between environmental conditions and presence and, consequently, catch of shark species in this program. Understanding these relationships could be useful to mitigate against unwanted catch and to further reduce risk for bathers.

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Geraghty, Pascal T., William G. Macbeth, Alastair V. Harry, Jacqueline E. Bell, Michelle N. Yerman, and Jane E. Williamson. "Age and growth parameters for three heavily exploited shark species off temperate eastern Australia." ICES Journal of Marine Science 71, no. 3 (November 13, 2013): 559–73. http://dx.doi.org/10.1093/icesjms/fst164.

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Abstract The removal of large predatory sharks from the world's oceans poses profound threats to marine community structure and species conservation. Effective management of exploited shark stocks requires a sound understanding of the life histories of target species. Here we provide the first assessment of age and growth for Carcharhinus brevipinna in Australian waters, and for C. obscurus and C. plumbeus in eastern Australian waters, based on interpretations of vertebral growth bands. In doing so, we provide arguably among the most robust growth parameters to date for the abovementioned taxa on the bases of genetic validation and sample size and distribution, but acknowledge equally a range of limitations—most notably those associated with vertebral ageing and our lack of age validation. Comparatively, the three species displayed both contrasts and consistencies in their growth characteristics off Australia's southeast coast. For all three sharks, rates of growth were greatest in the years immediately after birth, males grew more rapidly than females in the juvenile phase, and females were observed to grow larger, live longer and were generally larger at any given age. Longevity and all modelled growth parameters (L∞, k and L0), however, differed among the three species, and appeared to challenge the findings for conspecific populations in other parts of the world. The validity of these latter comparisons is, however, compromised by a range of confounding factors. Nevertheless, we provide the least conservative k estimates for C. obscurus and C. plumbeus of those previously reported, and extend maximum age estimates for C. brevipinna. In this way, our results have important implications for the assessment of natural mortality, productivity, and hence resilience to stock depletion, in these species in southeastern Australian waters.

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Gilbert, Jann M., Christine Baduel, Yan Li, Amanda J. Reichelt-Brushett, Paul A. Butcher, Shane P. McGrath, Victor M. Peddemors, Laurence Hearn, Jochen Mueller, and Les Christidis. "Bioaccumulation of PCBs in liver tissue of dusky Carcharhinus obscurus, sandbar C. plumbeus and white Carcharodon carcharias sharks from south-eastern Australian waters." Marine Pollution Bulletin 101, no. 2 (December 2015): 908–13. http://dx.doi.org/10.1016/j.marpolbul.2015.10.071.

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Braccini, Matias, and Stephen Taylor. "The spatial segregation patterns of sharks from Western Australia." Royal Society Open Science 3, no. 8 (August 2016): 160306. http://dx.doi.org/10.1098/rsos.160306.

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The extent to which sharks segregate by size and sex determines the population structure and the scale at which populations should be managed. We summarized 20 years of fisheries-dependent and independent sampling to define the spatial patterns of size and sexual segregation for sharks in Western Australia. Carcharhinus obscurus and C. plumbeus showed a large-scale (more than 1000 km) latitudinal gradient in size. Large individuals occurred predominantly in the northwest and north whereas smaller individuals occurred predominantly in the southwest and south. Mustelus antarcticus and Furgaleus macki showed strong sexual segregation at very large scales. Females occurred predominantly in the west and southwest whereas the proportion of males in catches substantially increased in the southeast. The populations of other shark species did not show sex and size segregation patterns at very large scales; most species, however, showed varying degrees of segregation when data were analysed at a smaller scale. These findings highlight the importance of matching the scale of observation to the scale of the phenomenon observed. As many shark species are highly mobile, if sampling is opportunistic and constrained both temporally and spatially, the observed segregation patterns may not be representative of those at the population level, leading to inaccurate scientific advice.

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BILECENOGLU, M., J. E. F. ALFAYA, E. AZZURRO, R. BALDACCONI, Y. Ö. BOYACI, V. CIRCOSTA, L. J. V. COMPAGNO, et al. "New Mediterranean Marine biodiversity records (December, 2013)." Mediterranean Marine Science 14, no. 2 (October 29, 2013): 463. http://dx.doi.org/10.12681/mms.676.

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Based on recent biodiversity studies carried out in different parts of the Mediterranean, the following 19 species are included as new records on the floral or faunal lists of the relevant ecosystems: the green algae Penicillus capitatus (Maltese waters); the nemertean Amphiporus allucens (Iberian Peninsula, Spain); the salp Salpa maxima (Syria); the opistobranchs Felimida britoi and Berghia coerulescens (Aegean Sea, Greece); the dusky shark Carcharhinus obscurus (central-west Mediterranean and Ionian Sea, Italy); Randall’s threadfin bream Nemipterus randalli, the broadbanded cardinalfish Apogon fasciatus and the goby Gobius kolombatovici (Aegean Sea, Turkey); the reticulated leatherjack Stephanolepis diaspros and the halacarid Agaue chevreuxi (Sea of Marmara, Turkey); the slimy liagora Ganonema farinosum, the yellowstripe barracuda Sphyraena chrysotaenia, the rayed pearl oyster Pinctada imbricata radiata and the Persian conch Conomurex persicus (south-eastern Crete, Greece); the blenny Microlipophrys dalmatinus and the bastard grunt Pomadasys incisus (Ionian Sea, Italy); the brown shrimp Farfantepenaeus aztecus (north-eastern Levant, Turkey); the blue-crab Callinectes sapidus (Corfu, Ionian Sea, Greece). In addition, the findings of the following rare species improve currently available biogeographical knowledge: the oceanic pufferfish Lagocephalus lagocephalus (Malta); the yellow sea chub Kyphosus incisor (Almuñécar coast of Spain); the basking shark Cetorhinus maximus and the shortfin mako Isurus oxyrinchus (north-eastern Levant, Turkey).

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Gilbert, Jann M., Amanda J. Reichelt-Brushett, Paul A. Butcher, Shane P. McGrath, Victor M. Peddemors, Alison C. Bowling, and Les Christidis. "Metal and metalloid concentrations in the tissues of dusky Carcharhinus obscurus , sandbar C. plumbeus and white Carcharodon carcharias sharks from south-eastern Australian waters, and the implications for human consumption." Marine Pollution Bulletin 92, no. 1-2 (March 2015): 186–94. http://dx.doi.org/10.1016/j.marpolbul.2014.12.037.

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Withers, P., G. Hefter, and TS Pang. "ROLE OF UREA AND METHYLAMINES IN BUOYANCY OF ELASMOBRANCHS." Journal of Experimental Biology 188, no. 1 (March 1, 1994): 175–89. http://dx.doi.org/10.1242/jeb.188.1.175.

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The possible role of urea and trimethylamine oxide (TMAO) in providing positive buoyancy has been examined for elasmobranch fishes. TMAO has a considerably lower density than an equimolar solution of urea, and solutions of both TMAO and urea are considerably less dense than equimolar solutions of most other body fluid solutes. The body fluid composition of three elasmobranchs, the whiskery shark Furgaleus ventralis, the black whaler shark Carcharhinus obscurus and the shovelnosed ray Aptychotremata vincentiana, is typical for marine elasmobranchs, with plasma concentrations of about 260 mmol l-1 Na+, 250 mmol l-1 Cl-, 340 mmol l-1 urea and 70 mmol l-1 trimethylamine oxide. A plasma density of 1.015 was calculated for the whaler shark (from the concentrations, relative molecular masses and absolute molal volumes of plasma solutes), which would contribute a positive lift of 8.45 g l-1. There is a large positive contribution to buoyancy by urea (3.7 g l-1), trimethylamine oxide (1.8 g l-1) and Cl- (4.0 g l-1), whereas slight negative buoyancy is conferred by Na+ (-0.8 g l-1). Divalent cations (Ca2+, Mg2+) contribute minimal negative buoyancy (about -0.1 g l-1 each) despite their rather negative partial molal volumes, because of their low concentrations. Muscle fluids contain about 40 mmol l-1 Cl-, 365 mmol l-1 urea, 160 mmol l-1 trimethylamine oxide, 16 mmol l-1 betaine and 69 mmol l-1 sarcosine. The organic solutes contribute about 12.1 g l-1 lift. Although urea and TMAO act as balancing osmolytes, and TMAO as a counteracting solute, a positive buoyancy role must be considered as a further adaptive function of urea and TMAO accumulation in chondrichthyean fishes.

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ARTICLE A, COLLECTIVE. "V. Gerovasileiou et al.: New Mediterranean Biodiversity Records (July, 2017)." Mediterranean Marine Science 18, no. 2 (July 31, 2017): 355. http://dx.doi.org/10.12681/mms.13771.

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This Collective Article presents information on 37 taxa belonging to 6 Phyla and extending from the western Mediterranean to the Levantine Sea. The new records were found in 10 countries as follows: Algeria: first reports on the presence of the fish species Lesueurigobius sanzi, L. friesii, L. suerii and Luvarus imperiali; France: first record of the alien nudibranch Godiva quadricolor; Italy: first record of an adult-sized red emperor snapper Lutjanus sebae from the southern Tyrrhenian Sea; first record of the pantropical rhodophyte Chondria curvilineata and the Lessepsian fish Siganus luridus from southern Sicily; record of a large pregnant female Dusky shark Carcharhinus obscurus off Sicily; Albania: first record of the fish Ruvettus pretiosus, new records of the alien molluscs Conomurex persicus, Bursatella leachii, Dendostrea cf. folium, Fulvia fragilis and Ruditapes philippinarum and additional report of the alien bivalve Pinctada imbricata radiata; Montenegro: first record of the sea slug Thecacera pennigera in the Adriatic Sea; Greece: first record of the invasive calcarean sponge Paraleucilla magna in Greek waters; occupancy estimation of the established cryptogenic rhodophyte Ganonema farinosum, the alien crustacean Percnon gibbesi and the alien fish species Fistularia commersonii, Siganus luridus, and S. rivulatus along the Cretan coastline; first record of the alien mollusc Sticteulima lentiginosa in Greek waters suggesting a westward unintentional expansion of this species; Turkey: photographic evidence of interactions of the monk seal Monachus monachus with sea-cage farms in the Turkish Aegean Sea and first record of the yellow boxfish Ostracion cubicus in the Turkish Mediterranean; Cyprus: first records of the rare speleophilic fish Thorogobius ephippiatus and Grammonus ater in Cyprus, extending the known distribution of the latter Mediterranean endemic species eastwards; first records of the alien fish Kyphosus vaigiensis and the alien crustacean species Macrophthalmus indicus and Carupa tenuipes as well as additional records of the alien echinoderm Diadema setosum and the alien ascidian Symplegma brakenhielmi in the country; Lebanon: first report on the presence of the four alien fish species Cephalopholis taeniops, Equulites popei, Pseudupeneus prayensis and Sphoeroides pachygaster; Egypt: first record of the Lessepsian fish Synchiropus sechellensis in the Egyptian Mediterranean waters.

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Bejarano-Álvarez, Olga Marcela, and Felipe Galván-Magaña. "First report of an embryonic dusky shark (Carcharhinus obscurus) with cyclopia and other abnormalities." Marine Biodiversity Records 6 (January 2013). http://dx.doi.org/10.1017/s1755267212001236.

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IRSAN, Ahmad, Fahma WİJAYANTİ, Yayan Mardiansyah ASSUYUTİ, and Ranny YUNENİ. "Fisheries and Biological Aspect of Dusky Whaler Shark (Carcharhinus obscurus, Lesueur 1818) in Muncar Fishing Port, Banyuwangi, Indonesia." Acta Aquatica Turcica, February 10, 2021. http://dx.doi.org/10.22392/actaquatr.812389.

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Huveneers, Charlie, Yuri Niella, Michael Drew, Rory McAuley, Paul Butcher, Victor Peddemors, Daniela Waltrick, et al. "Continental-Scale Network Reveals Cross-Jurisdictional Movements of Sympatric Sharks With Implications for Assessment and Management." Frontiers in Marine Science 8 (August 31, 2021). http://dx.doi.org/10.3389/fmars.2021.697175.

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Understanding the movement ecology of marine species and connectivity of populations is required for effective fisheries management. This is especially the case for species with wide-ranging distributions for which movement can span across several jurisdictions with different management regulations. We used the Australian national network of acoustic receivers facilitated by the Integrated Marine Observing System (IMOS) to describe the extent and frequency of movements for two large epipelagic shark species, the bronze whaler (Carcharhinus brachyurus) and dusky shark (Carcharhinus obscurus). A total of 210 sharks (117 bronze whalers and 93 dusky sharks) were tracked for a 10-year period during which 21% and 9% of detected bronze whalers and dusky sharks, respectively, moved between Australian states. Bronze whalers showed more variable inter-state movements, mostly between Western Australia and South Australia but also eastwards to New South Wales (NSW). Although no dusky sharks tagged in Western Australia undertook inter-state movements, ∼50% of the sharks tagged in South Australia went to Western Australia. Five of the 14 dusky sharks tagged in NSW (36%) were detected across different states but remained on the east and southeast coasts (Queensland, NSW, Victoria, and Tasmania). The IMOS receivers also detected six bronze whalers in Ningaloo Reef, representing an extension of the previously known Australian distribution. Our findings highlight the value of collaboration between researchers and the value of national infrastructure, by providing a more accurate understanding of inter-state movements. This new information will allow the development of more adequate population dynamic models for stock assessment and management advice, requiring collaboration among state agencies for coordinating research activities, sharing data and resources, and establishing appropriate cross-jurisdictional policies. This is essential to achieve successful management and conservation outcomes for highly migratory species.

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Kroetz, Andrea M., Simon J. B. Gulak, and John K. Carlson. "Horizontal and vertical movements of immature dusky sharks Carcharhinus obscurus in relation to commercial longline fisheries in the western North Atlantic Ocean." Animal Biotelemetry 9, no. 1 (August 21, 2021). http://dx.doi.org/10.1186/s40317-021-00258-8.

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Abstract Background Many species of sharks, including the dusky shark Carcharhinus obscurus, are often incidentally captured in commercial pelagic and bottom longline fisheries. Incidental capture can lead to at-vessel or post-release mortality and can be detrimental to populations of threatened, endangered, or prohibited species. The estimated at-vessel mortality for dusky sharks can be high in longline fisheries and, to minimize mortality, time–area closures have been designated in the western North Atlantic Ocean to mitigate interactions with longline fisheries, yet incidental capture of dusky sharks is still common. We compared the vertical and horizontal movements of dusky sharks to the overall fishing effort and depth fished of commercial pelagic and bottom longline fisheries to determine when and where overlap is present that could lead to incidental capture. Results Twenty-one (n = 21) dusky sharks were tagged with pop-up archival transmitting satellite tags and all were immature animals (123–200 cm FL) apart from two individuals (230 and 300 cm FL). Sharks were tagged off the coasts of North Carolina (71%) and Florida (29%). Twenty tags (95%) reported and provided tracks between 1 and 107 days (median 15 days) and 10 tags (50%) remained on sharks for > 4 days. Most individuals remained within the bottom longline closed area off the coast of North Carolina during their time at liberty. Dusky sharks primarily occupied the 20–40 m depth range 26% of the time, and overlapped with bottom and pelagic longline gears 41% and 59% of the time, respectively. Overlap was highest in the winter and spring for both commercial fisheries. Conclusions The use of archival satellite telemetry in this study has provided valuable preliminary information on vertical and horizontal movements of immature dusky sharks in western North Atlantic Ocean. Dusky sharks may be more vulnerable to incidental capture in the pelagic longline fishery due to the high fishing effort, larger areas of horizontal overlap, and greater percentage of vertical overlap. This information will inform mitigation measures of commercial longline fisheries, which can work toward population rebuilding of the species.

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Crear, Daniel P., Tobey H. Curtis, Stephen J. Durkee, and John K. Carlson. "Highly migratory species predictive spatial modeling (PRiSM): an analytical framework for assessing the performance of spatial fisheries management." Marine Biology 168, no. 10 (September 6, 2021). http://dx.doi.org/10.1007/s00227-021-03951-7.

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AbstractSpatial management for highly migratory species (HMS) is difficult due to many species’ mobile habits and the dynamic nature of oceanic habitats. Current static spatial management areas for fisheries in the United States have been in place for extended periods of time with limited data collection inside the areas, making any analysis of their efficacy challenging. Spatial modeling approaches can be specifically designed to integrate species data from outside of closed areas to project species distributions inside and outside closed areas relative to the fishery. We developed HMS-PRedictive Spatial Modeling (PRiSM), which uses fishery-dependent observer data of species’ presence–absence, oceanographic covariates, and gear covariates in a generalized additive model (GAM) framework to produce fishery interaction spatial models. Species fishery interaction distributions were generated monthly within the domain of two HMS longline fisheries and used to produce a series of performance metrics for HMS closed areas. PRiSM was tested on bycatch species, including shortfin mako shark (Isurus oxyrinchus), billfish (Istiophoridae), and leatherback sea turtle (Dermochelys coriacea) in a pelagic longline fishery, and sandbar shark (Carcharhinus plumbeus), dusky shark (C. obscurus), and scalloped hammerhead shark (Sphyrna lewini) in a bottom longline fishery. Model validation procedures suggest PRiSM performed well for these species. The closed area performance metrics provided an objective and flexible framework to compare distributions between closed and open areas under recent environmental conditions. Fisheries managers can use the metrics generated by PRiSM to supplement other streams of information and guide spatial management decisions to support sustainable fisheries.

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Journal articles on the topic 'Carcharhinus obscurus'

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