Sharks - Science topic

The scalloped hammerhead shark (Sphyrna lewini) is a Critically Endangered species with a circumglobal distribution that has declined because of unsustainable trade in its fins. Since 2014 its international trade is regulated through the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES). Recently, a Global Nort...

Freshwater or euryhaline sharks and rays are usually a forgotten component of shark, ray, and chimera biodiversity, mainly because the vast majority of these species are associated with marine ecosystems. Freshwater rays are cartilaginous fish species that have adapted and developed the ability to live and complete their entire life cycles in fresh...

In the 20 years since the IUCN SSC Shark Specialist Group’s first status report (2005), much has changed for sharks, rays and chimaeras. This report updates our understanding, and the scope of information reflects the scale of these two decades of change. The breadth of research topics has expanded, mirroring the inclusion of a greater diversity of...

Introduction: Interobserver reliability in interpreting cardiotocographs (CTGs) using traditional categorization into "normal," "suspicious," and "pathological" is typically very low ranging from Kappa 0.3 to 0.6. Physiological CTG interpretation focuses on identifying specific features of different types of fetal hypoxic stress and a combination...

Direct numerical simulation is performed for flow separation over a bump in a turbulent channel. Comparisons are made between a smooth bump and one where the lee side is covered with replicas of shark denticles – dermal scales that consist of a slender base (the neck) and a wide top (the crown). As flow over the bump is under an adverse pressure gr...

Throughout chondrichthyan evolution, significant adaptations have led to the establishment of rapid tooth replacement and the development of highly differentiated tooth mineralogies in modern sharks. By contrast, in some early chondrichthyans, tooth replacement was evidently much slower. Specifically, cladodonts are known to retain their teeth inst...

Abstrak: Sistem sangkar menjadi pilihan utama pengusaha akuakultur air tawar terutamanya tilapia dan patin di Sungai Pahang kerana kelebihan penggunaan air sungai yang mengalir, bekalan air yang berterusan dan dikatakan dapat mengurangkan rasa dan bau lumpur berbanding ternakan menggunakan sistem kolam tanah. Namun demikian, penternak menghadapi pe...

Recent advancements in the Internet of Things (IoT) have paved the way for intelligent and sustainable solutions in smart city environments. However, despite these advantages, IoT-connected devices present significant privacy and security risks, as network attacks increasingly exploit user-centric information. To protect the network against the rap...

Evolutionary transitions toward gigantic body sizes have profound consequences for the structure and dynamics of ecological networks. Among elasmobranchs (sharks and rays), gigantism has evolved on several occasions, most notably in the iconic Megalodon (Otodus megalodon †) and the extant whale shark (Rhincodon typus), basking shark (Cetorhinus max...

Elasmobranchs (shark sand rays) are critical components of coral reef ecosystems and are often considered indicators of reef health (Roff et al., 2016). Yet, they are experiencing global population declines and effective monitoring of these populations is essential to their protection. Underwater stationary videos, such as those from Baited Remote...

Length-weight relationships are valuable in fisheries biology for estimating a fish's average weight at a given length, aiding in predicting population conditions based on total biomass. This study presents length-weight relationships for six threatened shark species captured off the Brazilian Amazon Coast. The specimens of Carcharhinus porosus, Ca...

Trace fossils preserved with fossil worm-shaped remains suggest the presence of free-living flatworms during the Ordovician at the latest and their occurrence in terrestrial environments during the Permian. The presence of hooks associated with acanthodian and placoderm fishes indicates the existence of parasitic monopisthocotyleans, with a simple...

The discovery of a tooth of the cow shark Hexanchus microdon (Ag., 1835) from carbonate deposits of the Karsun Formation in the ‘Krasny Oktyabr’ quarry (Volsk, Saratov Volga River Right Bank) is described. Based on the associated foraminifera complex, the stratigraphic position of the find was determined as Lower Maastrichtian, benthic foraminifera...

Animal movements are typically influenced by multiple environmental factors simultaneously, and individuals vary in their response to this environmental heterogeneity. Therefore, understanding how environmental aspects, including biotic, abiotic, and anthropogenic factors, influence the movements of wild animals is an important focus of wildlife re...

The roughskin dogfish Centroscymnus owstonii, a deep‐sea shark, has a patchy global distribution, with most knowledge stemming from incidentally captured specimens. Using a deep‐sea remote lander video system, we observed multiple C. owstonii individuals alive on the footage at 1054 m off Little Cayman, Cayman Islands, Western Atlantic Ocean, marki...

Surface wettability, the interaction between a liquid droplet and the surface it contacts, plays a key role in influencing droplet behavior and flow dynamics. There is a growing interest in designing surfaces with tailored wetting properties across diverse applications. Advanced fabrication techniques that create surfaces with unique wettability of...

Introduction: Elasmobranchs, such as sharks and rays, are among the world’s most endangered vertebrates, with over 70% loss in abundance over the past 50 years due to human impacts. Zooarchaeological baselines of elasmobranch diversity, distribution, and exploitation hold great promise for contributing essential historical contexts in the assessmen...

Southern Brazil is home to a large biodiversity of elasmobranchs from the Brazilian coast. Several genera and species of small sharks of the Triakidae family live in this marine environment. Studies on these shark species are scarce, with few genetic data and little information on animal population structures. The present study aimed to sequence th...

The mode of evolution of left-right asymmetries in the vertebrate habenulae remains largely unknown. Using a transcriptomic approach, we show that in a cartilaginous fish, the catshark Scyliorhinus canicula, habenulae exhibit marked asymmetries, in both their medial and lateral components. Comparisons across vertebrates suggest that those identifie...

Stress and anxiety are significant psychological challenges in modern society, which have led to a rapidly growing market for functional foods, including those reported to relieve stress, as alternatives to psychoactive drugs. Among these, diacyl glyceryl ethers (DAGE) derived from deep-sea shark liver oil have gained attention for their strong ant...

Fishing is a fundamental economic activity in the development of coastal areas. However, it experiences processes of overexploitation, deterioration of ecosystems, increased social pressure, and administrative inefficiencies, among other challenges that compromise the sustainability and well-being of many highly dependent and highly vulnerable comm...

Organo-sedimentary deposits that result from fine-grained sediment trapping, binding, and likely precipitation (of carbonate) by microbes in flat-mat, branching, and dome-shaped constructions are termed microbialites. They were first identified as stromatolites by paleontologists well before the discovery of cyanobacteria that build the same kinds...

This study was conducted to analyze the catches of sharks, such as composition, length-weight relationship, and to determine the distribution of shark fishing areas. Every fishing activity has by-catch issues. Fishers commonly catch sharks as by-catch. These fishing activities will harm the shark ecosystem in the waters. This research was conducted...

A case of diprosopia anomaly in a blue shark (Prionace glauca) embryo from the South Atlantic Ocean is described. A detailed morphological description of internal organs was provided. The sample came from a pregnant female caught near Trindade Island (19°29'30”S, 028°20’00”W) in Southeast Brazil, with three normal embryos and one with external morp...

This paper proposes a two-raft wave energy conversion technology with bionic rafts, aiming to enhance the wave energy capture performance of existing devices with regularly shaped rafts. The cross-sectional shape of the bionic raft is designed as a nested pattern of the long and short axes of two semi-ellipses, which is inspired by the cross-sectio...

Northern Australia is considered a ‘lifeboat’ region for globally threatened shark and ray species (elasmobranchs), although much of the region is understudied. The Roper River in the Northern Territory’s Gulf of Carpentaria has been inadequately surveyed, with most elasmobranch data gained opportunistically through freshwater fish surveys. This st...

New approaches to abundance surveying utilizing unoccupied aerial vehicles (UAVs) are proving to be effective tools in marine and terrestrial environments. We explored UAV efficacy for surveys in the Galapagos Marine Reserve (GMR), where relative abundance patterns of juvenile sharks and subsequent classifications of putative nursery areas based on...

This study explores the capability of Convolutional Neural Networks (CNNs), a particular class of Deep Learning algorithms specifically crafted for computer vision tasks, to classify images of isolated fossil shark teeth gathered from online datasets as well as from the authors' experience on Peruvian Miocene and Italian Pliocene fossil assemblages...

The reproductive state of wild, free-swimming tiger sharks (Galeocerdo cuvier), was assessed using underwater ultrasonography at a diving site in Fuvahmulah, a Maldivian atoll within the central Indian Ocean. The presence of embryos were observed in 93% of the adult sharks (26/28) and two distinct embryonic size groups were observed within the subs...

El palangre de superficie es un arte pesca dirigido a la captura de peces pelágicos, el cual puede enganchar especies vulnerables como tiburones, tortugas, aves y mamíferos marinos. El objetivo del presente trabajo fue analizar la incidencia de estos grupos en la pesca de barcos nodrizas ecuatorianos. La base de datos fue proporcionada por el Insti...

The pelagic thresher shark (Alopias pelagicus) and bigeye thresher shark (Alopias superciliosus) are important shark species for Indonesia's consumption and finning industry. Both Alopias species are included in the CITES appendix II, thus requiring certain documents for trading. Regarding species identification for on-site application, the DNA iso...

On July 11, 2024, a single juvenile specimen of the little gulper shark Centrophorus uyato (Rafinesque, 1810) was caught by a commercial trawler off the coast of Silifke in the Gulf of Mersin (Northeastern Mediterranean Sea, Turkey) at a depth of about 568 m. All measurements, counts, and color descriptions of C. uyato agree with previous descripti...

It is widely accepted that populations of terrestrial predators sometimes contain “problem individuals” that repeatedly attackhumans, yet this phenomenon has never been demonstrated in sharks. Here, we present photographic and genetic evidence of individuals in populations of tiger Galeocerdo cuvier and oceanic whitetip Carcharhinus longimanus shar...

Killer whales occur in the Gulf of Mexico (GoMex) and the North Atlantic, including off the southeastern United States (SEUS). Data from cetacean surveys during 1990 – 2021 and other sources were combined to assess killer whale biology, including spatial and temporal distribution, social structure, genetics, morphology, acoustics, and predatory beh...

Scalloped hammerhead sharks (Sphyrna lewini) routinely perform rapid dives to forage on mesopelagic prey. These deep dives consist of intensive swimming followed by recovery periods in the surface mixed layer. Swimming muscle temperature profiles suggest that S. lewini suppresses gill function as a means to reduce convective heat loss during dives...

Australian pygmy blue whales (Balaenoptera musculus brevicauda) migrate between the waters off southern Australia and the tropics. They are known to feed off Timor and in the Banda Sea. On their return migration from the Banda Sea, blue whales pass by the coast of Timor-Leste, where they can be easily encountered by surface vessels in a nacent tour...

Morphological scaling describes changes in the size or shape of one morphological character (e.g. mass, length, width, area etc.) as another increases in size. Understanding how morphological characters scale with body size can shed light on how natural selection influences morphology, and the nature of ecomorphological relationships through ontoge...

Opportunistic records can provide valuable information on certain species, including the critically endangered porbeagle shark (Lamna nasus). This note documents the occurrence of three juveniles, with approximate 120‐, 88‐, and 85‐cm fork lengths respectively, observed along the coast of Asturias, Spain, in 2024. Given the three distinct scenarios...

RESUMO O objetivo deste trabalho foi fazer a descrição dos dentículos dérmicos e utilizar estes como ferramenta de identificação taxonômica em espécimes de tubarões e raias processados para consumo humano. Os indivíduos são oriundos de apreensões realizadas por órgãos de fiscalização ambiental no período entre 2018 e 2020. Para análise dos dentícul...

It is widely accepted that populations of terrestrial predators sometimes contain “problem individuals” that repeatedly attack humans, yet this phenomenon has never been demonstrated in sharks. Here, we present photographic and genetic evidence of individuals in populations of tiger Galeocerdo cuvier and oceanic whitetip Carcharhinus longimanus sha...

Aim: To examine the species richness, distribution and macroecological patterns of elasmobranch assemblages across a broad latitudinal gradient in the Eastern Pacific Ocean (EPO). Location: The study area encompasses the Pacific coast of the American continent, spanning from 65°N to 60°S, and extending from the coastline to approximately 1000 km of...

The skeletons of sharks and rays, fashioned from cartilage, and armored by a veneer of mineralized tiles (tesserae) present a mathematical challenge: How can the continuous covering be maintained as the skeleton expands? This study, using microCT and custom visual data analyses of growing stingray skeletons, systematically examines tessellation pat...

Fisher-shark conflict is occurring at Lord Howe Island, Australia due to high levels of Galapagos shark (Carcharhinus galapagensis) depredation (where sharks consume hooked fish) and bycatch. Depredation causes costly loss of target catch and fishing gear and increased mortality of target species, and sharks can be injured or killed when bycaught....

Suspension system is one of the important Subsystems in an ATV. It ensures both safety and comfort of the driver. The main aim of this paper is to design the suspension system of an ATV and explain the suspension parameters that have a significant impact on other subsystems such as the frame, braking, and steering. The study of relations between su...

The lack of reliable fishing data poses a challenge for sustainable shark management in Mexico. Fishery-dependent landings surveys of longline catches were conducted in Paredón (state of Chiapas), the primary shark fishing locality in the northern Gulf of Tehuantepec between March 2021 and April 2022. The local fishing fleet consists of 30 fibergla...

Aim The Mediterranean Sea is one of the most anthropized seas in the world but also a marine biodiversity hotspot with many fish species under threat. The main goal of the study is to test whether on the heavily fished and anthropized Mediterranean coast, the less impacted Corsica and Balearic Islands, can be considered as refugia for threatened an...

Chondrichthyans (sharks, rays, skates, and chimaeras) make up one of the oldest and most ecologically diverse vertebrate groups, yet they face severe threats from fishing, necessitating improved management strategies. To effectively manage these species, we need to understand their spatial interactions with fisheries. However, this understanding is...

Eocene climate cooling, driven by the falling pCO2 and tectonic changes in the Southern Ocean, impacted marine ecosystems. Sharks in high‐latitude oceans, sensitive to these changes, offer insights into both environmental shifts and biological responses, yet few paleoecological studies exist. The Middle‐to‐Late Eocene units on Seymour Island, Antar...

One of the chief consequences of climate change is the worldwide redistribution of species in the pursuit of physiologically and ecologically favourable conditions. As part of one of the most threatened groups of vertebrates, assessing how climate change may affect the distribution patterns of key shark species is essential for their long-term cons...

Scoliodon is a genus of small placental sharks living in offshore waters. For a long time, the genus was considered a monotypic genus until a valid species, Scoliodon macrorhynchos, was confirmed in 2010. However, S. muelleri in the same study was not widely recognized because of the lack of evidence. In this study, we obtained the complete mitocho...

Silky shark (Carcharhinus falciformis) populations in the South Atlantic Ocean are listed as vulnerable under the IUCN. In fact, this species is classified as critically endangered in Brazil under the Ministry of the Environment. The present study reports the first opportunistic sighting of an aggregation of 250–300 silky sharks in the Alcatrazes A...

Nowadays, wireless sensor networks (WSNs) are the central means for data gathering in the edge-based internet of things era. Mobile edge nodes, such as mobile sinks (MSs), are the most reasonable way to gather the sensed data in these WSNs by travelling through rendezvous points (RPs) across the region of interest. Nevertheless, effective path plan...

The Ouled Abdoun Basin lies to the west of the Atlas Mountains in Morocco. The largest (9000km2) of five major phosphate basins in the country, it is worked commercially and contains deposits ranging from Late Cretaceous (Maastrichtian) to Early Paleogene (basal Lutetian) in age. Believed to be related to offshore nutrient upwellings, the phosphate...

Background/Objectives: For years, research has been conducted on the relationship between anti-inflammatory diets and the incidence and risk of various diseases. In recent years, much attention has been paid to the beneficial effects of fish oil (FO) or shark liver oil (SLO) consumption, which is increasingly being used clinically. Health benefits...

Sharks are notorious for their exceptional dental diversity, which is frequently used as a proxy for ecological function. However, functional inferences from morphology need to consider morphological features across different organizational scales, from small cusplets to patterns at the level of the entire jaw. Here, we deploy a set of classic and...

In the context of low-carbon energy transformation, fully utilizing the integrated demand response (IDR) resources on the load side can improve the operational flexibility and economy of the integrated energy system (IES). However, establishing a reasonable trading mechanism to enhance users’ participation in IDR has become a key issue that IES urg...

The current Community Service Partner has been carried out at the Bekasi Javanese Christian Church West so that of the existing congregations, there are several congregations who are entangled with these online loans and find it difficult to repay the online loans, and not a few of the congregations end up in contact with debt collector officers. W...

Age data are essential for estimating life history parameters and are thus critical for population assessment, management, and conservation. Traditional vertebrae-based age estimation in elasmobranchs can be costly, time intensive, of low accuracy, and is by necessity lethal. Herein, epigenetic clocks were developed for an elasmobranch, the cownose...

Keywords: dynamic Brownian bridge movement model earth mover's distance elasmobranch endangered movement ecology wildlife provisioning By changing the spatiotemporal availability of resources, tourism-related feeding can have potentially detrimental impacts on the movement ecology of animals, thus possibly undermining its own conservation benefits....

Mammoth Cave National Park (MACA) in central Kentucky holds the longest cave system in the world, with cave passages cutting through Middle to Upper Mississippian limestones. These limestones hold records of fish assemblages, mostly dominated by chondrichthyans, that are primarily identified from isolated teeth, spines, and occasional skeletal cart...

The Upper Cretaceous Western Interior Seaway (WIS) of North America is best known for its diverse assemblage of marine vertebrates, namely marine reptiles, birds, sharks, turtles, and bony fish. The majority of previous studies has been based on macrofossil remains, such as partial cranial and/or post-cranial skeletons. Recent analyses of microvert...

This study presents a circularly-polarized (CP) planar monopole antenna designed for ultra-wideband (UWB) applications using characteristic mode analysis (CMA). Initially, a planar monopole antenna with a crescent moon-shaped radiator and a circular open-loop on an FR-4 substrate was designed to achieve wideband characteristics, however, this anten...