Literatura académica sobre el tema "Hammerhead sharks"
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Artículos de revistas sobre el tema "Hammerhead sharks"
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Barker, Amanda M., Douglas H. Adams, William B. Driggers, Bryan S. Frazier y David S. Portnoy. "Hybridization between sympatric hammerhead sharks in the western North Atlantic Ocean". Biology Letters 15, n.º 4 (abril de 2019): 20190004. http://dx.doi.org/10.1098/rsbl.2019.0004.
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Hybridization between closely related species has been documented across a wide range of taxa but has not been well studied in elasmobranchs. Hammerhead sharks have drawn global conservation concern because they experience some of the highest mortality rates among sharks when interacting with fisheries. Here we report on the detection of hybrids between the globally distributed scalloped hammerhead ( Sphyrna lewini ) and recently described Carolina hammerhead ( S. gilberti ) which are only known from the western Atlantic Ocean. Using a genomics approach, 10 first-generation hybrids and 15–17 backcrosses were detected from 554 individuals. The identification of backcrosses demonstrates hybrids are viable, and all backcrosses but one involved a scalloped hammerhead. All hybrids but one possessed Carolina hammerhead mtDNA, indicating sex-biased gene flow between species. Repeated hybridization and backcrossing with scalloped hammerheads could lead to the loss of endemic Carolina hammerheads.
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Alaudin, Alaudin, Jaliadi Jaliadi y Burhanis Burhanis. "SEBARAN UKURAN DAN PERTUMBUHAN HIU MARTIL (BY CATCH) YANG DIDARATKAN DI PANGKALAN PENDARATAN IKAN (PPI) UJONG BAROH MEULABOH". JURNAL PERIKANAN TROPIS 8, n.º 1 (3 de junio de 2021): 65. http://dx.doi.org/10.35308/jpt.v8i1.2595.
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Hammerhead shark is a type of predator shark belongs to the family of Sphyrnidae. This shark is so aggressive in hunting prey such as fish, squid, and shrimp. The hammerhead shark in Indonesia is included in Appendix II of CITES and has been a special concern in the field of capture fisheries. The aim of the study was to see the size spread, the number of catches, the first size caught, the age growth and the genital ratio of the hammerhead sharks caught with the base fish net. The study was conducted from October to December 2019. The shark measurement was performed once in 2 weeks. Sharks caught by the gills of the base (buttom gilt net) were measured using a roll meter. The collection of hammerhead sharks included total length (TL), number of catches and genital ratio. The analysis was done descriptively using the ELEFAN I existing on Sofwere FiSAT II. The results showed that the hammerhead sharks caught with an gill net of 65 tails from October to December 2019 were taken on the male genital. The total size spread of female malletic sharks were between 61.5-131.5 cm and male hammering sharks between 61.5-111.5 cm. The morphologically spread of the female hammerhead was relatively longer than the male shark. The male hammerhead shark was first captured at a length of 117.9 cm and a female hammerhead shark at a size of 106.2 cm. Hammerhead shark growth by following the curve of von Bertalanffy mallet were male Lt = 138,08 (1-exp (-0.480 (t + 0.0487)) and female mallet shark Lt = 138,08 (1-exp (-0.430 (t + 0.0434)). Such equations can be known by using the relationship curve model between the age and length of fish.
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Bahri, S., N. Hikmah y N. Fadli. "Relationship analysis of Scalloped Hammerhead (Sphyrna lewini) from West Aceh Waters using molecular genetics approach". IOP Conference Series: Earth and Environmental Science 1137, n.º 1 (1 de enero de 2023): 012016. http://dx.doi.org/10.1088/1755-1315/1137/1/012016.
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Abstract Hammerhead sharks are particularly vulnerable to fishing because of their slow growth rate and reproductive constraints. This type of sharks needs special attention due to its conservation status. This research was aimed to describe the relationships of the hammerhead sharks from West Aceh waters with the hammerhead sharks from other places. Samples of the shark were collected from Ujong Baroh Fish Port, West Aceh. The samples were analysed at the Laboratory of Department of Marine Science and Fisheries, Syiah Kuala University. The laboratory activity was started with extraction of DNA enhanced by Polymerase Chain Reaction method and visualized by an electrolytical. Analysis using BLAST showed that the first sample obtained 94%-95% cover query value and produced a 683 base pair length while the second sample obtained 98% per sample for a cover query value and produced a 658 base pair length. The average nucleotide values of the hammerhead shark were T=32.8, C=26.6, A=25.7 and G=14.9. The phylogenetic tree shows that the hammerhead sharks from the study area were more similar to the hammerhead sharks from Australia and Malaysia. Overall, based on the nucleotide composition, phylogenetic tree and genetic distance, the hammerhead sharks from the study area are unique compared to the populations from the other places.
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Anna, Zuzy, Purna Hindayani, Asep Agus Handaka Suryana, Yudi Nurul Ihsan y Asia Salsabila. "Sustainability Study of Scalloped Hammerhead Shark (Sphyrna lewini) in Indramayu Waters". Sustainability 12, n.º 24 (14 de diciembre de 2020): 10459. http://dx.doi.org/10.3390/su122410459.
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Hammerhead shark (Sphyrna lewini) population decline is a global problem experienced by various ocean basins worldwide, including Indramayu waters. As the regency known by its fishery barn that supplies 65% of captured fisheries in West Java, Indonesia, illegal fishing practices towards this protected species is inevitable. In 2017, 2869 tons of sharks were landed in Indramayu with the production value of IDR 44.01 billion, which hammerhead shark catch reaches 268 tons. This research aimed to observe the sustainability of hammerhead shark in Indramayu waters using a bio-economic model of Gordon Schaefer (GS) and Gompertz. The results showed the overfishing of hammerhead shark in Indramayu waters on actual conditions in 2012, 2014, 2015, 2016, 2017, and 2018, both in the GS and Gompertz models. The abundant number of hammerhead sharks started to deplete from 2015 to 2018, and the highest depletion was found in 2017, with a depletion value of 16 tons and depreciation value of IDR 164 million. The depletion rate suffered the most significant decline in 2011 to 2012 for all types of sharks, including hammerhead. The prohibition of consistent fishing and more pronounced law enforcement for hammered shark fishing are needed to maintain the sustainability of this resource.
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Piercy, Andrew N., John K. Carlson y Michelle S. Passerotti. "Age and growth of the great hammerhead shark, Sphyrna mokarran, in the north-western Atlantic Ocean and Gulf of Mexico". Marine and Freshwater Research 61, n.º 9 (2010): 992. http://dx.doi.org/10.1071/mf09227.
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The great hammerhead shark, Sphyrna mokarran, is a cosmopolitan species that is caught in a variety of fisheries throughout much of its range. The apparent decline of great hammerhead shark populations has reinforced the need for accurate biological data to enhance fishery management plans. To this end, age and growth estimates for the great hammerhead were determined from sharks (n = 216) ranging in size from 54- to 315-cm fork length (FL), captured in the Gulf of Mexico and north-western Atlantic Ocean. Growth curves were fitted using multiple models and evaluated using Akaike’s information criterion. The von Bertalanffy growth model was the best fitting model, with resulting growth parameters of L∞ = 264.2-cm FL, k = 0.16 year–1, t0 = –1.99 year for males, and L∞ = 307.8-cm FL, k = 0.11 year–1, t0 = –2.86 year for females. Annual band pair deposition was confirmed through marginal-increment analysis and a concurrent bomb radiocarbon validation study. Great hammerheads have one of the oldest reported ages for any elasmobranch (44 years) but grow at relatively similar rates (on the basis of von Bertalanffy k value) to other large hammerhead species from this region. The present study is the first to provide vertebral ages for great hammerheads.
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Kajiura, Stephen M. y Kim N. Holland. "Electroreception in juvenile scalloped hammerhead and sandbar sharks". Journal of Experimental Biology 205, n.º 23 (1 de diciembre de 2002): 3609–21. http://dx.doi.org/10.1242/jeb.205.23.3609.
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SUMMARY The unique head morphology of sphyrnid sharks might have evolved to enhance electrosensory capabilities. The `enhanced electroreception' hypothesis was tested by comparing the behavioral responses of similarly sized carcharhinid and sphyrnid sharks to prey-simulating electric stimuli. Juvenile scalloped hammerhead sharks Sphyrna lewini and sandbar sharks Carcharhinus plumbeus oriented to dipole electric fields from the same maximum distance (approximately 30 cm) and thus demonstrated comparable behavioral-response thresholds (<1 nV cm-1). Despite the similarity of response threshold, the orientation pathways and behaviors differed for the two species. Scalloped hammerheads typically demonstrated a pivot orientation in which the edge of the cephalofoil closest to the dipole remained stationary while the shark bent its trunk to orient to the center of the dipole. By contrast, sandbars swam in a broader arc towards the center of the dipole. The different orientation patterns are attributed to the hydrodynamic properties of the cephalofoil, which enables the hammerheads to execute sharp turns at high speed. The greater trunk width of the sandbar sharks prevented them from demonstrating the same degree of flexibility. Therefore, although the sphyrnid head morphology does not appear to confer a greater sensitivity to prey-simulating dipole electric fields, it does provide(1) a greater lateral search area, which may increase the probability of prey encounter, and (2) enhanced maneuverability, which may aid in prey capture.
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Marcotte, Megan M. y Christopher G. Lowe. "Behavioral Responses of Two Species of Sharks to Pulsed, Direct Current Electrical Fields: Testing a Potential Shark Deterrent". Marine Technology Society Journal 42, n.º 2 (1 de junio de 2008): 53–61. http://dx.doi.org/10.4031/002533208786829133.
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To describe and contrast the behavioral responses of two species of sharks to an electrical deterrent, sharks were baited to a food odor source within a strong pulsed, direct current electrical field. A head twitch behavior was elicited in scalloped hammerhead (Sphyrna lewini) and leopard sharks (Triakis semifasciata) at mean voltage gradient thresholds of 4.16 ± 0.59 V/m (X ± SD) and 4.30 ± 0.78 V/m, respectively, and did not differ significantly. A shimmy behavioral response was elicited in some hammerhead sharks at a mean threshold of 5.54 ± 1.55 V/m. A retreat behavioral response occurred in hammerhead and leopard sharks at a mean, maximum threshold of 18.50 ± 13.27 V/m and 9.64 ± 10.28 V/m, respectively. The hammerhead sharks retreated at significantly stronger field strengths than the leopard sharks, suggesting that some species may require stronger electrical fields for effective deterrence. Both species of shark remained significantly further away and spent less time near the food odor source when the electrical field was on versus off. The maximum voltage gradient threshold required to cause the sharks to retreat was much higher than previously reported, and the electrical field was not 100% effective at excluding sharks. The sharks only retreated after involuntary muscle contractions were induced by the electrical field.
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Taylor, Stephen, Wayne Sumpton y Tony Ham. "Fine-scale spatial and seasonal partitioning among large sharks and other elasmobranchs in south-eastern Queensland, Australia". Marine and Freshwater Research 62, n.º 6 (2011): 638. http://dx.doi.org/10.1071/mf10154.
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Our understanding of the ecological role of larger elasmobranchs is limited by a lack of information on their spatial and seasonal abundance. Analysis of 14 years of gill-net catch data in south-eastern Queensland, Australia, revealed that the species composition of large sharks and other elasmobranchs significantly differed among beaches and seasons. Spinner sharks (Carcharhinus brevipinna) and hammerhead sharks (Sphyrna spp.) comprised nearly half the catch of all elasmobranchs. Although the distribution of these sharks overlapped, spatial variation existed in their abundance. Spinner sharks characterised the catch at Sunshine Coast beaches, whereas the catch at Gold Coast beaches was dominated by hammerhead sharks. Seasonal differences in elasmobranch community structure were also apparent, driven largely by a lower abundance of many species during the winter and the predominance of species such as spinner sharks and hammerheads in spring and summer. The present study provides the first quantitative data for numerous species of Carcharhiniformes in south-eastern Queensland and demonstrates that analysis of catch-rate data can improve our understanding of how larger sharks partition resources.
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Lowe, Christopher y Gwen Goodman-Lowe. "Suntanning in hammerhead sharks". Nature 383, n.º 6602 (octubre de 1996): 677. http://dx.doi.org/10.1038/383677a0.
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Bezerra, Natalia P. A., Bruno C. L. Macena, Paulo Travassos, Pedro Afonso y Fábio H. V. Hazin. "Evidence of site fidelity and deep diving behaviour of scalloped hammerhead shark (Sphyrna lewini) around the Saint Peter and Saint Paul Archipelago, in the equatorial Mid-Atlantic ridge". Marine and Freshwater Research 71, n.º 6 (2020): 708. http://dx.doi.org/10.1071/mf19029.
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Seven scalloped hammerhead sharks (Sphyrna lewini) were satellite tagged around the Saint Peter and Saint Paul Archipelago (SPSPA), located at the equatorial Mid-Atlantic ridge, to investigate their vertical and horizontal movements. All sharks remained in the surroundings of the SPSPA over the course of the 120-day monitoring period, suggesting a high degree of medium-term site fidelity. During this period, scalloped hammerhead sharks covered a wide extension of the water column, ranging from the mixed layer to the mesopelagic zone. All sharks remained in warm (>22°C) shallow layers most of the time, but also dove to depths greater than 150m, mostly at night, eventually reaching 728m (5.6°C) on two occasions. This study contributes important, novel information on the habitat use and movement patterns of scalloped hammerhead shark in Atlantic equatorial oceanic waters. It also highlights the potential of protecting key, large oceanic areas as a useful tool for the conservation of this endangered species.
Tesis sobre el tema "Hammerhead sharks"
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Lowe, Christopher G. "Bioenergetics and swimming efficiency of juvenile scalloped hammerhead sharks, Sphyrna lewini, in Kaneohe Bay, Oahu, Hawaii". Thesis, University of Hawaii at Manoa, 1998. http://hdl.handle.net/10125/18160.
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The goal of this study was to determine the energetic
requirements of juvenile scalloped hammerhead sharks (Sphyrna
lewini) in Kaneohe Bay, Oahu, Hawaii using a multidisciplinary
approach. A large flume/respirometer (635 1)
was constructed to determine the critical swimming speeds
(Ucrit )' swimming kinematics (tailbeat frequency, tailbeat
amplitude, and stride length), and oxygen consumption rates
(V02 ) of juvenile sharks over a range of swimming speeds (U).
Swimming kinematics were also compared with unconstrained
sharks in a seawater pond. These experiments indicated that
tailbeat frequency (TBF) and water temperature could be used
as a predictor of U and V02 for free-swimming sharks in the
field; however, the flume affected the sharks' swimming
kinematics at slow speeds. The flume and pond kinematic
comparisons were used to correct for flume effects on sharks'
V02.
An acoustic tailbeat-sensing transmitter was designed
and constructed to quantify activity and energy consumption
of free-swimming hammerhead shark pups in Kaneohe Bay.
Sharks with transmitters behaved similarly to uninstrumented
sharks, but incurred a 28% increase in cost of transport due
to increased drag from the transmitters. These data were
used to correct for the effects of the transmitter on freeswimming
sharks in the field. Sharks tracked in Kaneohe Bay with tailbeat transmitters
exhibited increased U during dawn and dusk, while sharks
tracked in the warmer summer months had higher activity rates
and metabolic rates (MR) than a shark tracked during the
winter. Sharks tracked in this study had higher MR than
those measured for other species of tropical sharks and, as a
result, require higher daily rations. Low and negative
growth rates determined from sharks in the Bay and declining
catch rates over the season suggest that a large percentage
of the pups in Kaneohe Bay may starve as the result of their
high metabolic requirements. Although prey do not appear to
be li~itingi lack of foraging experience compounded by a high
daily metabolic demand may explain why sharks lose weight
during summer months. Those pups that survive the winter
experience lower MR due to seasonal temperature decline and
less competition as the result of high neonatal mortality.x, 130 leaves, bound : ill. (some col.) ; 29 cm.
Missing page 74.
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Gustafson, Johann A. "Hammerhead sharks (Sphyrnidae) of southeast Queensland: habitat and movements". Thesis, Griffith University, 2020. http://hdl.handle.net/10072/397639.
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Hammerhead sharks (Sphyrnidae) are iconic and charismatic species that have received little attention until more recently, resulting in knowledge gaps about life histories, habitats, behaviours and migratory drivers, mostly in the southern hemisphere such as Australian waters. Globally, shark populations are declining as many species extinction risk has increased under the threat of fishing and habitat degradation. Hammerhead shark (Sphyrnidae) populations are highly susceptible to human-induced pressure such as long lines and are currently undergoing severe declines, especially in Australia. Recently, hammerhead sharks have been added to the International Union for Conservation of Nature’s (IUCN) Red List of Threatened Species, with scalloped hammerhead listed as critically endangered. Therefore, further information is needed to address the current shortfalls regarding hammerheads in Australia, for the management and conservation of these species.
Earlier research using catch data from the Queensland Shark Control Program (QSCP) showed a decline in numbers of caught hammerhead sharks since the start of the program in 1960. A review of the literature (CHAPTER 1) revealed that hammerhead sharks were understudied in Australia, with information shortfalls on movement, resource use, nursery areas and habitat use. The general aim of this thesis was to provide a better understanding of the movement, distribution, habitat use and resource use of scalloped hammerhead shark (Sphyrna lewini) in Queensland, Australia to improve conservation and management strategies. I used multiple methodologies to determine (i) the distribution of suitable habitat for juvenile scalloped hammerhead sharks and the percentage of overlap with marine protected areas (CHAPTER 2); (ii) fine-scale movement of juvenile scalloped hammerheads within these habitats and determine behavioural states using high-resolution acoustic tracking (CHAPTER 3); (iii) thermal tolerance range “thermal niche” of hammerhead shark using historical catch records from the QSCP (CHAPTER 4); and (iv) resource overlap between hammerhead sharks species and with other co-existing large sharks using carbon and nitrogen stable isotopes (CHAPTER 5). This allowed me to build a solid baseline framework of the ecology of scalloped hammerhead sharks in Queensland.
The species distribution model identified 10,082.87 km2 of suitable habitat characterised by low current velocities (< 0.5 m-s), warm sea surface temperatures (> 20°C), estuarine/oceanic salinities (25-35 PSU) and shallow bathymetries (< 20 m). Suitable habitats occurred in coastal areas within wetland and seagrass habitats. Highly suitable areas accounted for 1,784.33 km2 of the total distribution and
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occurred around highly developed areas, such as Moreton Bay, Hervey Bay, Townsville and Cairns. Coastal beach areas of the Gold Coast were also uncovered as highly suitable habitats and may be due to close proximity of the Gold Coast seaway and Tweed River connections to more sheltered estuarine habitats. The majority of the predicted suitable distribution occurred within the lower protection multi-use zones (6,291.20 km2) and outside marine protected areas (3,791.67 km2); where no-take zones protected only 11 % and 8.56 % of high and medium modelled suitable habitats. Within these habitats, continuous tracking of two juvenile scalloped hammerhead sharks uncovered highly active diving behaviours where both sharks continuously dove from water surface to the bay floor over 12- and 3-hour tracks. Two diving patterns were observed in both sharks and described as A-type: one long dive with multiple small dives at depth, and B-type dives: one long dive without extra dives at depth. The two-state behavioural model uncovered low activity (forage) and high activity (direction) states, which were influenced by distance to seagrass and coral habitats as well as habitat depth.
Quantile regression modelling determined catches of hammerhead sharks in relation to changes in seas surface temperatures changed with latitude along the Queensland coast. Scalloped hammerhead catches in the southern areas were most likely to occur between 20℃ - 25℃ and likely to occur throughout the year in the northern areas, as sea surface temperatures remained above 22℃. Co-existing bull (Carcharias leucas) and tiger (Galeocerdo cuvier) sharks also occurred throughout this thermal range while white shark (Carcharodon carcharias) only occurred below 23℃. Stable isotope analysis revealed scalloped and great hammerhead sharks overlapped 69% in isotopic space and with several large shark species. Both hammerhead species undertook a seasonal dietary shift, and scalloped hammerheads showed a wider δ13C and lower δ15N than the more specialised great hammerhead. Tiger sharks feed at a lower trophic level overlapping mostly with both hammerhead sharks. White and bull sharks competed with hammerhead sharks at higher δ15N.
Overall, results from my research make original contributions to the knowledge of hammerhead sharks by identifying previously unreported distributions of suitable juvenile habitats of the scalloped hammerhead, which occurred in developed areas and within multi-use protection zones. Additionally, the research described previously unreported diving patterns and state-switching of juvenile hammerhead sharks within highly developed areas, highlighting the importance of wetland and estuarine habitats for shark conservation. Furthermore, the research showed high overlap in resource use between two endangered hammerhead species with several large predatory shark species. In iii summary, this thesis highlights the relevance of movement and habitat use information in the conservation and management of endangered iconic shark speciesThesis (PhD Doctorate)
Doctor of Philosophy (PhD)
School of Eng & Built Env
Science, Environment, Engineering and Technology
Full Text
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Mara, Kyle Reid. "Evolution of the Hammerhead Cephalofoil: Shape Change, Space Utilization, and Feeding Biomechanics in Hammerhead Sharks (Sphyrnidae)". Scholar Commons, 2010. http://scholarcommons.usf.edu/etd/3502.
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The relationship between form and function is often used to elucidate the biological role of a structure. Hammerhead sharks offer a unique opportunity to study form and function through phylogeny. Because sphyrnid sharks display a range of cranial morphologies this group can be used to address questions about the evolution of cranial design and investigate the effects of changes in head morphology on feeding structures and bite force. Geometric morphometrics, volumetric analyses, morphological dissections, and phylogenetic analyses of the cephalofoil were used to gain insight into changes in cranial design through evolutionary history. External morphometrics and internal volumetric analyses indicated that while the external shape of the cephalofoil and placement of the sensory structures is variable through evolutionary history, the volumes of the internal cranial elements do not change. Constructional constraints within the cephalofoil were confined to sensory structures while feeding morphology remained relatively unchanged. Analysis of the morphology and biomechanics of the feeding apparatus revealed that through phylogeny the feeding system does not change among sphyrnid species. However, size-removed bite force was lower than predicted for all sphyrnid species except Sphyrna mokarran. Despite differences in head morphology between sphyrnid and carcharhinid sharks, the feeding bauplan is conserved in sphyrnid sharks with few changes to the feeding structures. Instead the chondrocranial and sensory structures are modified around the relatively static feeding core. Finally, the durophagous S. tiburo was found to consume hard prey in a manner that is biomechanically and morphologically different from other durophagous fishes. Furthermore, the diet of S. tiburo is constrained by the properties of its preferred prey.
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Abercrombie, Debra. "Efficient PCR-Based Identification of Shark Products in Global Trade: Applications for the Management and Conservation of Commercially Important Mackerel Sharks (Family Lamnidae), Thresher Sharks (Family Alopiidae) and Hammerhead Sharks (Family Sphyrnidae)". NSUWorks, 2004. http://nsuworks.nova.edu/occ_stuetd/131.
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Shark populations worldwide are suspected to be in severe decline due to domestic and international markets for trade in shark products, especially dried fins in Asian markets, and as a result of bycatch mortality in multi-species fisheries. The management of sharks on a species-specific basis has become imperative for shark conservation, particularly in regions where numerous species are heavily fished, because sharks with differing life-history characteristics respond differently to exploitation. However, many commercially exploited sharks are morphologically similar and not easily identifiable to the species level. This problem is exacerbated when it comes to identifying detached fins, processed carcasses (logs), and filets or steaks at the dock or in trade.
To address these species-identification problems and make available an accurate but practical, DNA-based forensic method for use in conservation and management of sharks, I have developed a highly streamlined genetic assay based on multiplex polymerase chain reaction (PCR) and species-specific primers derived from interspecific DNA sequence differences in the nuclear ribosomal internal transcribed spacer 2 (ITS2) locus of sharks. This forensic assay allows accurate identification of body parts from ten shark species commonly exploited worldwide for their meat and/or fins. In this thesis, I report on the development and use of this assay in the form of two separate suites of species-specific PCR primers that can be used in a high-density multiplex format to achieve rapid and accurate species identification. Chapter 1 of this thesis describes a suite of species-specific primers and multiplex PCR assay that simultaneously distinguishes among seven pelagic shark species: four species of mackerel sharks: shortfin mako (Isurus oxyrinchus), longfin mako (Isurus paucus), porbeagle (Lamna nasus) and salmon (Lamna ditropis); and the three species of alopiid (thresher) sharks: common thresher (Alopias vulpinus), bigeye thresher (Alopias superciliosus) and pelagic thresher (Alopias pelagicus). The second species-specific primer suite, described in chapter 2, simultaneously identifies the three globally distributed and most commercially important species of hammerheads: the great hammerhead (Sphyrna mokarran), scalloped hammerhead (Sphyna lewini) and the smooth hammerhead (Sphyrna zygaena).
The species-specific PCR primers and forensic approach described here provide an efficient, straightforward technique that can be used in conservation and management relevant contexts where large volumes of samples need to be screened quickly. Preliminary testing of dried fins from the Hong Kong market and confiscated fins from U.S. and South African law enforcement activities suggests that this genetic technique will be useful for large-scale survey applications, such as monitoring the species composition of the fin trade as well as improving fisheries law enforcement capabilities. The efficient nature of the general forensic approach reported here may also make it useful as a model applicable to monitoring trade in other wildlife products on a global scale.
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Hayes, Christopher Glenn. "Investigating single and multiple species fisheries management: stock status evaluation of hammerhead (Sphyrna spp.) sharks in the western North Atlantic Ocean and Gulf of Mexico". Thesis, Virginia Tech, 2007. http://hdl.handle.net/10919/30989.
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Three hammerhead sharks (Sphyrna spp.) are currently managed as part of the large coastal shark complex in the United States. Including multiple species in an assessment ignores the different stock dynamics of each individual species within the complex due to different life histories. This study completed individual assessments of scalloped (S. lewini), great (S. mokarran), and smooth (S. zygaena) hammerhead sharks in the U.S. Atlantic Ocean and Gulf of Mexico. Combined data for all three species and unclassified hammerhead sharks were also used to produce a stock assessment of the hammerhead shark complex. Depletions of 83%, 96%, and 91% were estimated for scalloped, great, and smooth hammerhead sharks, respectively, between 1981 and 2005. When modeled as a single stock, the hammerhead shark complex experienced a 90% decline over the same time period. All three stocks, and the complex were overfished (below population size associated with maximum sustainable yield (MSY)), and overfishing (fishing level above that associated with MSY) occurred in 2005. We found that scalloped hammerhead shark population recovery is likely to occur within 10 years if catch remains at or below 2005 levels. Great and smooth hammerhead sharks will likely still be overfished in 30 years unless catches are reduced.
It appears that the species composition could be changing in this hammerhead shark complex. The faster-growing scalloped hammerhead sharks are able to withstand fishing pressure better than great or smooth hammerhead sharks. However, it is difficult to target any single large coastal shark species while fishing; hence they are subject to similar fishing pressure. The result is a greater decline in great and smooth hammerhead sharks than experienced by scalloped hammerhead sharks. Therefore, the proportion of scalloped hammerhead sharks increased between 1981 and 2005. Species-specific stock assessments, such as those presented here, allow managers to more closely monitor populations of slower-growing species and reduce the risk of overexploitation of those species.Master of Science
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Horn, Rebekah L. "Applying a Molecular Genetics Approach to Shark Conservation and Management: Assessment of DNA Barcoding in Hammerhead Sharks and Global Population Genetic Structuring in the Gray Reef Shark, Carcharhinus amblyrhynchos". NSUWorks, 2010. http://nsuworks.nova.edu/occ_stuetd/218.
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Chapter 1
DNA barcoding based on the mitochondrial cytochrome c oxidase subunit I (COI) gene sequence is emerging as a useful tool for identifying unknown, whole or partial organisms to species level. However, the application of only a single mitochondrial marker for robust species identification has also come under some criticism due to the possibility of erroneous identifications resulting from species hybridizations and/or the potential presence of nuclear-mitochondrial psuedogenes. The addition of a complementary nuclear DNA barcode has therefore been widely recommended to overcome these potential COI gene limitations, especially in wildlife law enforcement applications where greater confidence in the identifications is essential. In this study, we examined the comparative nucleotide sequence divergence and utility of the mitochondrial COI gene (N=182 animals) and nuclear ribosomal internal transcribed spacer 2 (ITS2) locus (N=190 animals) in the 8 known and 1 proposed cryptic species of globally widespread, hammerhead sharks (family Sphyrnidae). Since hammerhead sharks are under intense fishing pressure for their valuable fins with some species potentially set to receive CITES listing, tools for monitoring their fishery landings and tracking trade in their body parts is necessary to achieve effective management and conservation outcomes. Our results demonstrate that both COI and ITS2 loci function robustly as stand-alone barcodes for hammerhead shark species identification. Phylogenetic analyses of both loci independently and together accurately place each hammerhead species together in reciprocally monophyletic groups with strong bootstrap support. The two barcodes differed notably in levels of intraspecific divergence, with average intraspecific K2P distance an order of magnitude lower in the ITS2 (0.297% for COI and 0.0967% for ITS2). The COI barcode also showed phylogeographic separation in Sphyrna zygaena, S. lewini and S. tiburo, potentially providing a useful option for assigning unknown specimens (e.g. market fins) to a broad geographic origin. We suggest that COI supplemented by ITS2 DNA barcoding can be used in an integrated and robust approach for species assignment of unknown hammerhead sharks and their body parts in fisheries and international trade.
Chapter 2
The gray reef shark (Carcharhinus amblyrhynchos) is an Indo-Pacific, coral reef associated species that likely plays an important role as apex predator in maintaining the integrity of coral reef ecosystems. Populations of this shark have declined substantially in some parts of its range due to over-fishing, with recent estimates suggesting a 17% decline per year on the Great Barrier Reef (GBR). Currently, there is no information on the population structure or genetic status of gray reef sharks to aid in their management and conservation. We assessed the genetic population structure and genetic diversity of this species by using complete mitochondrial control region sequences and 15 nuclear microsatellite markers. Gray reef shark samples (n=305) were obtained from 10 locations across the species’ known longitudinal Indo-Pacific range: western Indian Ocean (Madagascar), eastern Indian Ocean (Cocos [Keeling] Islands, Andaman Sea, Indonesia, and western Australia), central Pacific (Hawaii, Palmyra Atoll, and Fanning Atoll), and southwestern Pacific (eastern Australia – Great Barrier Reef). The mitochondrial and nuclear marker data were concordant in most cases with population-based analysis showing significant overall structure (FST = 0.27906 (pST = 0.071 ± 0.02), and significant pairwise genetic differentiation between nearly all of the putative populations sampled (i.e., 9 of the 10 for mitochondrial and 8 of the 10 for nuclear markers). Individual-based analysis of microsatellite genotypes identified at least 5 populations. The concordant mitochondrial and nuclear marker results are consistent with a scenario of very low to no appreciable connectivity (gene flow) among most of the sampled locations, suggesting that natural repopulation of overfished regions by sharks from distant reefs is unlikely. The results also indicate that conservation of genetic diversity in gray reef sharks will require management measures on relatively local scales. Our findings of extensive genetic structuring suggests that a high level of genetic isolation is also likely to be the case in unsampled populations of this species.
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McCallister, Michael Philip. "Abundance, Distribution, and Habitat Use of Sharks in Two Northeast Florida Estuaries". UNF Digital Commons, 2012. http://digitalcommons.unf.edu/etd/352.
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Sharks are considered top predators in many marine ecosystems, and can play an important role in structuring those communities. As a result, it is necessary to understand the factors that influence their abundance and distribution. This is particularly important as fishery managers develop fishery management plans for sharks that identify areas that serve as essential fish habitat (EFH). This includes nursery habitat where sharks are born and juveniles spend the early part of their life. However, our understanding of shark habitat use in the northeast Florida waters is limited. The goal of this thesis was to characterize the abundance and distribution of sharks in northeast Florida estuaries, and to examine the effect of abiotic and biotic factors affecting shark habitat use. A bottom longline survey conducted from 2009 – 2011 indicated that 11 shark species use the estuarine waters of northeast Florida during summer months. Atlantic sharpnose (Rhizoprionodon terraenovae), blacktip (Carcharhinus limbatus), bonnethead (Sphyrna tiburo), and sandbar sharks (Carcharhinus plumbeus) were the most abundant species and made up 87.1% of the total catch. Month, bottom water temperature, and depth were the most important factors determining the presence and abundance of these species. This study also examined the role of prey abundance in determining the abundance of Atlantic sharpnose sharks. The probability of catching an Atlantic sharpnose shark, and the abundance of Atlantic sharpnose sharks, were most influenced by site. Neither potential prey abundance nor preferred prey abundance were not significant factors effecting Atlantic sharpnose abundance. This may be a result of prey sampling not providing an accurate measure of the true availability of prey resources. Other factors, such as predation risk, may better explain habitat use patterns of Atlantic sharpnose sharks. Continued sampling will give a better understanding of the factors influencing shark habitat use in this area.
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Ballesta, Artero Irene Maria. "Influence of the Estimator Selection in Scalloped Hammerhead Shark Stock Assessment". Thesis, Virginia Tech, 2014. http://hdl.handle.net/10919/24819.
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In natural sciences, frequentist paradigm has led statistical practice; however, Bayesian approach has been gaining strength in the last decades. Our study assessed the scalloped hammerhead shark population on the western North Atlantic Ocean using Bayesian methods. This approach allowed incorporate diverse types of errors in the surplus production model and compare the influences of different statistical estimators on the values of the key parameters (r, growth rate; K carrying capacity; depletion, FMSY , fishing levels that would sustain maximum yield; and NMSY, abundance at maximum sustainable yield). Furthermore, we considered multi-levelpriors due to the variety of results on the population growth rate of this species. Our research showed that estimator selection influences the results of the surplus production model and therefore, the value of the target management points. Based on key parameter estimates with uncertainty and Deviance Information Criterion, we suggest that state-space Bayesian models be used for assessing scalloped hammerhead shark or other fish stocks with poor data available. This study found the population was overfished and suffering overfishing. Therefore, based on our research and that there was very low evidence of recovery according with the last data available, we suggest prohibition of fishing for this species because: (1) it is highly depleted (14% of its initial population), (2) the fishery status is very unstable over time, (3) it has a low reproductive rate contributing to a higher risk of overexploitation, and (4) the easiness of misidentification among different hammerhead sharks (smooth, great, scalloped and cryptic species).Master of Science
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Kotas, Jorge Eduardo. "Dinâmica de populações e pesca do tubarão-martelo Sphyrna lewini (Griffith & Smith, 1834), capturado no mar territorial e zona econômica exclusiva do sudeste-sul do Brasil". Universidade de São Paulo, 2004. http://www.teses.usp.br/teses/disponiveis/18/18139/tde-08122015-105215/.
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O tubarão-martelo, Sphyrna lewini é um dos mais valiosos recursos marinhos, e o preço pago por suas barbatanas no mercado Asiático pode atingir acima dos U$ 100,00/kg. A análise da composição de tamanhos e idades nas capturas, o estudo do crescimento desta espécie de grande porte e a evolução temporal dos desembarques, indicaram que este recurso se encontra sobreexplotado no sudeste e sul do Brasil, como reflexo de diferentes modalidades pesqueiras atuando ao longo de todo o seu ciclo de vida e à baixa resiliência desta espécie à pesca, por apresentar um crescimento lento (L∞ = 329,12 cm; K = 0,071 ano-1; to = -2,37 ano; sexos combinados), longevidade acima dos 40 anos e mortalidade natural baixa (M = 0,1 ano-1 na fase adulta), padrões estes típicos de uma espécie K-estrategista . A sobrepesca de recrutamento, ocorre nas áreas costeiras, principalmente pela pesca de arrasto e emalhe costeiro, não havendo a proteção das áreas de parto na primavera-verão. Neste caso há grandes capturas de neonatos e juvenis até 8 anos de idade. A tração adulta por sua vez é reduzida pela pesca de espinheI e de emalhe de superfície principalmente na zona de talude. Modelos de análise de covariância indicaram maiores capturas desta espécie na pesca de espinheI de monofilamento de superfície durante os meses de primavera-verão, na zona de talude (200 e 3000 m) e a existência de uma relação linear positiva entre a captura em peso e o esforço em número de anzóis. Medidas de manejo e conservação para esta espécie são sugeridas.The scalloped hammerhead shark Sphyrna lewini is one of the most valuable marine resources, due to its high-priced fins in the Asian market, which can reach U$ 100,00/kg. The analysis of the length and age composition in the catches, growth studies, and the annual development of its landings in southern Brazil, showed signs of overexploitation for the species. This effect was mainly caused by different fishing gears exploiting all the phases of its life-cycle and its low resilience to fishing pressure due to its slow-growing strategy (L∞ = 329,12 cm; K = 0,071 yr-1; to = -2,37 ano; both sexes), longevity (> 40 yrs.) and low natural mortality (M = 0,1 yr-1, during adult phase), which means a K\'strategic typical pattern. Recruitment overfishing use to happen in coastal areas by trawls and anchored gillnets activities which destroy the nurseries and juvenile grounds for the species, mainly in spring-summer months when the parturition occurs. On the other hand, the adult fraction of the stock is reduced by surface longline and driftnets activities along the continental slope. For the surface monofilament longline fisheries, covariance models detected the highest catches of scalloped hammerhead sharks along the slope (between 200 - 3000 m depth), during spring-summer months. There was also a positive linear relationship between catch (in weight) and effort (hook number). Management and conservation measures are recommended for this species.
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Nelson, Jennifer A. "Comparative evaluation of the extended and minimal hammerheads suggests a shared dynamic pathway". Connect to online resource, 2007. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:3284472.
Texto completoLibros sobre el tema "Hammerhead sharks"
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Sarah, Palmer. Hammerhead sharks. Vero Beach, Fla: Rourke Enterprises, 1988.
Buscar texto completoCapítulos de libros sobre el tema "Hammerhead sharks"
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Cavalcanti, Mauro J. "Geometric morphometric analysis of head shape variation in four species of hammerhead sharks (Carcharhiniformes: Sphyrnidae)". En Morphometrics, 97–113. Berlin, Heidelberg: Springer Berlin Heidelberg, 2004. http://dx.doi.org/10.1007/978-3-662-08865-4_8.
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Peña, Alvaro, Noel Pérez, Diego S. Benítez y Alex Hearn. "Hammerhead Shark Species Monitoring with Deep Learning". En Applications of Computational Intelligence, 45–59. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-69774-7_4.
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"Hammerhead Sharks (Sphyrnidae)". En Shore Fishes of Hawaii, 23. University of Hawaii Press, 1996. http://dx.doi.org/10.1515/9780824844479-007.
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"Shark Nursery Grounds of the Gulf of Mexico and the East Coast Waters of the United States". En Shark Nursery Grounds of the Gulf of Mexico and the East Coast Waters of the United States, editado por DOUGLAS H. ADAMS y RICHARD PAPERNO. American Fisheries Society, 2007. http://dx.doi.org/10.47886/9781888569810.ch11.
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<em>Abstract.</em>—This study provides information regarding an open-ocean, nearshore nursery ground for the scalloped hammerhead <em>Sphyrna lewini </em>off the Atlantic coast of Florida near Cape Canaveral. Neonate scalloped hammerheads collected from this region ranged in size from 385 to 500 mm in total length (TL) and were observed during May and June, when water temperatures ranged from 26.1°C to 28.8°C. Although nearshore gill-net sampling during the study period encompassed the Florida Atlantic coastline from north of Cape Canaveral (latitude 28°40’N) south to the Jupiter Island area (latitude 27°04’N), neonate scalloped hammerheads were collected only in waters near the Cape Canaveral area. The nearshore waters near Cape Canaveral served as a nursery ground for scalloped hammerheads in 1994 and 1997. Extensive fisheries-independent gill-net sampling within the adjacent northern Indian River Lagoon system (Banana River Lagoon and Indian River Lagoon proper) did not collect scalloped hammerheads, indicating that this estuarine area does not serve as a nursery ground for this species. Other shark species collected in the overall study area included juvenile nurse sharks <em>Ginglymostoma cirratum </em>(620–1,219 mm TL); juvenile blacktip sharks <em>Carcharhinus limbatus </em>(630–885 mm TL); neonate, juvenile, and adult Atlantic sharpnose sharks <em>Rhizoprionodon terraenovae </em>(305–1,000 mm TL); juvenile and adult bonnethead <em>Sphyrna tiburo </em>(430–1,150 mm TL); and neonate and juvenile bull sharks <em>C. leucas </em>(754–1,460 mm TL). Human access to a portion of the open-ocean area near Cape Canaveral is currently prohibited due to security issues at the adjacent National Aeronautics and Space Administration’s Kennedy Space Center and Cape Canaveral Air Force Station. This area closure has inadvertently created a marine reserve by eliminating fishing pressure on and significantly reducing vessel- or shore-based human interaction with this nearshore habitat. The effects, if any, of this marine reserve on shark populations in the region are unknown, and studies regarding these and other aspects of shark abundance and distribution in the Cape Canaveral area are currently ongoing.
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"Shark Nursery Grounds of the Gulf of Mexico and the East Coast Waters of the United States". En Shark Nursery Grounds of the Gulf of Mexico and the East Coast Waters of the United States, editado por GLENN R. PARSONS y ERIC R. HOFFMAYER. American Fisheries Society, 2007. http://dx.doi.org/10.47886/9781888569810.ch19.
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<em>Abstract.</em>—From October 1997 to September 2000, we conducted a survey of shark nursery grounds in the northern Gulf of Mexico extending from Bay St. Louis, Mississippi to Perdido Bay, Alabama. The objectives of the survey were to identify shark pupping/nursery grounds, determine their extent, and characterize the environmental conditions prevalent. Collections were made from March to October of each year with at least four sites sampled each month, two sites in Mississippi waters and two sites in Alabama waters. Collections were made using a gill net fished from 1500 until 2200 hours each day. A total of 100 collections were made during the study, resulting in the capture of more than 2,200 sharks. Young-of-the-year and juvenile sharks were collected from many areas in the Mississippi Sound with many sharks taken around Cat, Ship, Horn, Petit Bois, Round, and Dauphin islands. Shark populations along the Mississippi and Alabama gulf coasts are dominated by three species, the Atlantic sharpnose shark <em>Rhizoprionodon terraenovae</em>, the blacktip shark <em>Carcharhinus limbatus</em>, and the finetooth shark <em>C. isodon. </em>Other species captured included the bull shark <em>C. leucas</em>, the scalloped hammerhead <em>Sphyrna lewini</em>, the bonnethead <em>S. tiburo</em>, the spinner shark <em>C. brevipinna, </em>the blacknose shark <em>C. acronotus</em>, and the sandbar shark <em>C. plumbeus</em>. We used analysis of variance to compare the environmental factors present at sites where sharks were present with those at sites where sharks were not present and found significant differences in surface and bottom dissolved oxygen when Atlantic sharpnose sharks were present, surface and bottom temperature and surface dissolved oxygen when finetooth sharks were present, and surface and bottom temperature when blacktip sharks were present. We used unweighted poisson regression to examine the effect of environmental factors on catch per unit effort (CPUE) (sharks 100 m net<sup>–1</sup> h<sup>–1</sup>) and found that surface salinity significantly altered catch of Atlantic sharpnose sharks, surface and bottom temperature and surface dissolved oxygen significantly altered finetooth shark CPUE, and both surface and bottom temperature and dissolved oxygen altered blacktip shark CPUE. To consider interspecific interactions between the three dominant species, we used the Yule coefficient of association and found that young of the year of the three most common species were significantly, positively associated. Future studies of shark abundance and distribution should consider the interactions between co-occurring species. The Mississippi Sound, associated barrier islands, and the lower reaches of the Mobile Bay are important nursery grounds for several shark species, particularly blacktip, Atlantic sharpnose, and finetooth sharks.
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"Shark Nursery Grounds of the Gulf of Mexico and the East Coast Waters of the United States". En Shark Nursery Grounds of the Gulf of Mexico and the East Coast Waters of the United States, editado por GLENN F. ULRICH, CHRISTIAN M. JONES, WILLIAM B. DRIGGERS, J. MARCUS DRYMON, DOUGLAS OAKLEY y CATHERINE RILEY. American Fisheries Society, 2007. http://dx.doi.org/10.47886/9781888569810.ch8.
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<em>Abstract.</em>—Sharks were collected from the estuarine and nearshore waters of South Carolina in an effort to delineate nursery grounds for coastal sharks within state waters. From March 1998 through December 2003, 4,098 sharks, representing 12 species, were collected using gill-net and hand-deployed longline fishing gears provided by the Cooperative Atlantic States Shark Pupping and Nursery Survey. To supplement these data, records of 6,648 shark captures, representing 16 species, from a long-term longline survey in South Carolina coastal waters were incorporated into the analyses. The results of this study indicate that the estuarine and nearshore waters of South Carolina represent an important primary nursery area for finetooth sharks <em>Carcharhinus isodon</em>, blacktip sharks <em>C. limbatus</em>, sandbar sharks <em>C. plumbeus</em>, Atlantic sharpnose sharks <em>Rhizoprionodon terraenovae</em>, and scalloped hammerheads <em>Sphyrna lewini</em>.
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Gordon, Robert B. "Independent Artisans". En A Landscape Transformed. Oxford University Press, 2000. http://dx.doi.org/10.1093/oso/9780195128185.003.0006.
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By 1730 New England colonists needed increasingly large amounts of iron for their expanding economy. Shipsmiths forged iron fastenings used in the vessels they built for the coastal and West Indian trades. The mariners who sailed these ships wanted large, strong iron anchors. Millwrights needed waterwheel axles and gudgeons, spindles, and numerous other iron components for gristmills, sawmills, fulling mills, and oil mills. Builders of the forges and furnaces that smelted and shaped iron products had to have iron hammerheads and forge plates. The pioneers on the frontier in New York and northern New England wanted massive iron kettles for boiling potash, usually the first cash crop they got off their newly cleared land. Everyone needed nails. Building a bloomery forge offered an adventurer in Connecticut’s Western Lands the easiest way to start making iron. One man could run a forge, although a helper made the work easier. The bloomery proprietor needed less capital than would be required for other types of ironworks. The region had plenty of easily developed water privileges of the right size to power a bloomery forge. Although it took skill and practice to make high-quality metal, a forge owner or hired hand could learn enough of the bloom smelting technique from an experienced smith within a few months to make serviceable metal. Iron of ordinary quality satisfied most people’s needs in the early days of the northwest. If the weather were bad, ore or fuel were unavailable, crops demanded attention, or the market of iron were slow, the proprietor could easily shut down his forge at short notice and restart it as soon as conditions improved. Although a bloomery forge could be part of an enterprise employing fifty or more hands, it could also be little more than a smithy in size and complexity. A farmer could accumulate enough money to build one. Alternatively, a number of individuals might take shares in a forge run by a single artisan. The proprietors of a mercantile business, or of grist or sawmills on the same or a nearby water privilege, could easily add a bloomery to their other enterprises.
Actas de conferencias sobre el tema "Hammerhead sharks"
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Pena, Alvaro, Noel Perez, Diego S. Benitez y Alex Hearn. "Tracking Hammerhead Sharks With Deep Learning". En 2020 IEEE Colombian Conference on Applications of Computational Intelligence (ColCACI). IEEE, 2020. http://dx.doi.org/10.1109/colcaci50549.2020.9247911.
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Zarea, Munir, Evan Brown, Allen George, Joshua Kozsey, Tyler Palmgren, Meng-Chien Wu, Sarah Oman, John Parmigiani, Joseph Piacenza y Susan Piacenza. "Analysis of Shark Fluid Dynamics to Guide Satellite Telemetry Tag Development". En ASME 2022 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2022. http://dx.doi.org/10.1115/imece2022-94838.
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Abstract Sharks are powerful predators that make long-range migrations across vast swaths of the ocean. Scientists attach satellite telemetry tracking tags to sharks in order to gather data on behavior, movement patterns and habitat usage. However, hydro-dynamic loading from these tags may unintentionally influence the host shark’s behavior, although the extent of the loading is still not well understood. While tag manufacturers have made incremental improvements to make tags lighter and smaller, there is still not a clear understanding between tag design and host animal impacts. This fundamental knowledge gap makes the design of telemetry tags difficult when aiming to minimize hydrodynamic effects. In this paper, we present an approach intended to help inform tag design. In addition, a case study demonstrates this approach using 3D digital models discussed in the introduction. Four different shark species: the great hammerhead (Sphyrna mokarran), shortfin mako (Isurus oxyrinchus), blacktip reef (Carcharhinus limbatus), and Caribbean reef (Carcharhinus perezii). We used computational fluid dynamics (CFD) methods to estimate baseline drag and lift coefficients from a range of angles of attack to simulate the sharks ascending, descending, and swimming horizontally. We solved lift and drag coefficients through force reports integrated into the CFD software, STAR-CCM+. The simulations were solved with the Menter shear stress transport (SST) k-ω turbulence model at steady-state. Across species, the drag and lift coefficients ranged from 0.14 – 0.21 and −0.02 – 0.37, respectively. To visualize the fluid dynamics, we created plots of pressure distribution and fluid flow associated with each shark’s average cruising speeds, providing insight for future researchers investigating optimal tag placement that minimizes the tag’s impact. To validate the computational models, we performed wind tunnel testing by using 3D printed models of each shark, allowing us to empirically measure lift and drag forces. A three-axis sting-balance style measurement system with strain gauges was used, while considering wind speed, fluid density, and matched Reynolds numbers associated with the CFD models for each species. Finally, we statistically compared the computational and wind tunnel measurements. Moving forward, we will explore the changes in drag and lift with different satellite tag models attached to the shark species. Our findings will support development of a methodology to quantify the hydrodynamic impact of different tag designs on sharks. This can be used by future researchers to determine the lift and drag forces a shark experiences with a satellite telemetry tag attached. Ultimately, this information will help to better monitor sharks in their natural environment and provide information that can be useful to the conservation of the species.
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Ulloa, Gabriela, Vicente A. Vasconez, Diego S. Benitez, Noel Perez y Alex Hearn. "Hammerhead Shark Detection Using Regions with Convolutional Neural Networks". En 2020 IEEE ANDESCON. IEEE, 2020. http://dx.doi.org/10.1109/andescon50619.2020.9272036.
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Ali, Asif, Kashif Zafar y Taimur Bakhshi. "On Nature-Inspired Dynamic Route Planning: Hammerhead Shark Optimization Algorithm". En 2019 15th International Conference on Emerging Technologies (ICET). IEEE, 2019. http://dx.doi.org/10.1109/icet48972.2019.8994757.
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Jenkins, Emily, Elizabeth Madura, Lindsay Cocotis y Helen Yuan. "The Great Hammerhead Shark: The use of ecological indicators to highlight pressures in the Philippines". En The 3rd Global Virtual Conference of the Youth Environmental Alliance in Higher Education. Michigan Technological University, 2021. http://dx.doi.org/10.37099/mtu.dc.yeah-conference/april2021/all-events/12.
Texto completoInformes sobre el tema "Hammerhead sharks"
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James Anderson, James Anderson. Stealth tagging of adult Scalloped Hammerhead sharks in Hawai'i. Experiment, marzo de 2015. http://dx.doi.org/10.18258/4907.
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David Shiffman, David Shiffman. What are Critically Endangered hammerhead sharks doing in the waters off Miami? Experiment, julio de 2022. http://dx.doi.org/10.18258/28336.
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