814 results on '"chondrichthyes"'
Search Results
2. The elasmobranchs of <scp>Malpelo Flora</scp> and <scp>Fauna Sanctuary</scp> , <scp>Colombia</scp>
- Author
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Pelayo Salinas-de-León, Edgar E. Becerril-García, Edgar M. Hoyos-Padilla, Felipe Ladino, Sandra Bessudo, and Charles M. Shepard
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Conservation of Natural Resources ,Fauna ,Colombia ,Aquatic Science ,Biology ,biology.organism_classification ,Deep sea ,Chondrichthyes ,Fishery ,Taxon ,Threatened species ,Sharks ,Animals ,IUCN Red List ,Marine protected area ,Ecosystem ,Ecology, Evolution, Behavior and Systematics ,Visual census - Abstract
Management and conservation actions in marine-protected areas require baselines for monitoring threatened marine fauna such as elasmobranchs. This article provides evidence of the occurrence of 34 species of elasmobranchs (21 sharks and 13 batoids) in the Malpelo Flora and Fauna Sanctuary, Colombia, including five new records of sharks and three of rays. From 1987 to 2021, new records were obtained by underwater visual census using SCUBA, manned submersibles and deep-ocean cameras to depths of up to 2211 m. Of the recorded species, 21 are considered as threatened taxa (64%) by the IUCN, making the Malpelo Flora and Fauna Sanctuary an essential conservation area for this highly threatened group of species.
- Published
- 2021
3. Occurrence of the bigeye thresher shark, Alopias superciliosus (Lowe, 1841) (Elasmobranchii, Alopiidae) in the southwestern Gulf of Mexico
- Author
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Jorge Pérez-Díaz, Tao Hernández-Arellano, Luis Fernando Del Moral-Flores, and Eduardo López-Segovia
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pelagic sharks ,Adult female ,biology ,Bigeye thresher shark ,Mesopelagic zone ,Pelagic zone ,western Atlantic ,Aquatic Science ,Oceanography ,biology.organism_classification ,Chondrichthyes ,Alopias superciliosus ,Fishery ,Geography ,Elasmobranchii ,Lamniformes ,new record - Abstract
The bigeye thresher shark Alopias supeciliosus is a large epipelagic and mesopelagic species, and it has a wide distribution in the Atlantic. However, its record in the Gulf of Mexico is sporadic. A single adult female of A. superciliosus, measuring 360 cm total length and about weight 165 kg, was caught by artisanal fishers in Salinas Roca Partida, Veracruz, Mexico, on July 14, 2020. This study reports the first occurrence of this species in the southwestern of the Gulf of Mexico, which extends its geographical distribution in Mexico.
- Published
- 2021
4. Report of zonetail butterfly ray, Gymnura zonura (Bleeker, 1852) and mangrove stingray Urogymnus granulatus (Macleay 1883) (Chondrichthyes: Myliobatiformes) from Andaman waters, India
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Ravi Ranjan Kumar, K. V. Akhilesh, K. K. Bineesh, and S. Venu
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0106 biological sciences ,Myliobatiformes ,Urogymnus ,biology ,Range (biology) ,010604 marine biology & hydrobiology ,04 agricultural and veterinary sciences ,Aquatic Science ,Oceanography ,biology.organism_classification ,01 natural sciences ,Chondrichthyes ,Fishery ,Butterfly ray ,Stingray ,040102 fisheries ,0401 agriculture, forestry, and fisheries ,Gymnura zonura ,Mangrove - Abstract
This paper reports the occurrence of two stingray species from Andaman waters, India; the zonetail butterfly ray Gymnura zonura (Bleeker, 1852) (695 mm DW) which represents a new distributional range, and the mangrove stingray Urogymnus granulatus (Macleay 1883) (395 mm DW) which represents a rare occurrence. These occurrences suggest hidden stingray diversity in this region. Morphological descriptions of both species, as well as a molecular barcode of G. zonura, were generated in the present study to clarify the taxonomic information. The current report assists in improving the understanding of the local diversity and distribution of batoids in Andaman waters, which is crucial for developing fishery management strategies.
- Published
- 2021
5. First record of clasper malformation of Pseudobatos buthi (Chondrichthyes: Rhinobatidae) in the Gulf of California
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Rosa Isabel Ochoa-Báez, Gabriela García-Vázquez, Julio C. Martínez-Ayala, Felipe Galván-Magaña, and Katherin Soto-López
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0106 biological sciences ,Cadmium ,Pseudobatos ,biology ,010604 marine biology & hydrobiology ,chemistry.chemical_element ,Zoology ,Heavy metals ,Histology ,Zinc ,Aquatic Science ,Clasper ,biology.organism_classification ,010603 evolutionary biology ,01 natural sciences ,Chondrichthyes ,chemistry ,Reproductive system - Abstract
Elasmobranchs in the Gulf of California have been found with malformations, probably originated during embryonic development or caused by environmental anomalies and pollution associated with intense mining activity in the region. Clasper malformations are reported for the first time in two specimens of Pseudobatos buthi, a species recently described from the Gulf of California. The function of the claspers was not affected by the size difference, because specimens presented the distinctive characteristics of an adult individual. The reproductive system did not show any malformation, with symmetrical testes. Histological analysis of the testes revealed a normal spermatogenic development. To elucidate the causes and to detect a possible effect of the morphological malformations due to high levels of heavy metals, trace concentration values (cadmium, copper, iron, manganese, silver, lead and zinc) were determined in muscle and liver. Cadmium and lead concentrations in the muscle of the two specimens were below the permissible limit for human consumption (−1); however, iron and zinc presented high values (0.455, 4.024 mg kg−1 in muscle and 21.931, 3.694 mg kg−1 in liver respectively). Mining activity and heavy metal pollution in the sampling area may have caused the malformations, which might be attributed to the high values of iron and zinc discovered in the muscle and liver.
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- 2021
6. First confirmed record of the occurrence of the lesser devil ray, Mobula hypostoma (Elasmobranchii, Mobulidae), in the southwestern Gulf of Mexico
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Luis Fernando Del Moral-Flores, Itzel Meza-Abundio, and Horacio Pérez-España
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Morphometrics ,biology ,Rare species ,Zoology ,devil ray ,western Atlantic ,Aquatic Science ,Oceanography ,biology.organism_classification ,Chondrichthyes ,humanities ,Geography ,Elasmobranchii ,Mobula hypostoma ,Mobula ,distribution ,geographic locations ,morphometry - Abstract
Nine specimens (one female and eight males, all juveniles) of lesser devil ray, Mobula hypostoma (Bancroft, 1831), were caught in the southwest Gulf of Mexico. These specimens represent the first record of the species in the Mexican waters. The disk width ranged between 552 and 773 mm. Morphometrics data are consistent with previously published records. Because of the number of specimens captured, we suggest that it is not a rare species in the southwest Gulf of Mexico.
- Published
- 2020
7. Sharks and rays caught by a small‐scale fisheries in the western equatorial Atlantic
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Jones Santander-Neto and Vicente Vieira Faria
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Fishery ,Scale (ratio) ,Endangered species ,Aquatic Science ,Biology ,biology.organism_classification ,Chondrichthyes - Published
- 2020
8. Sharks, rays, and chimaeras of the Revillagigedo National Park: An update of new and confirmed records
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Brad Henning, Pelayo Salinas de León, Edgar E. Becerril-García, and Edgar M. Hoyos-Padilla
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0106 biological sciences ,Conservation of Natural Resources ,Parks, Recreational ,Biodiversity ,Endangered species ,Aquatic Science ,010603 evolutionary biology ,01 natural sciences ,Deep sea ,Megafauna ,Animals ,Mexico ,Ecology, Evolution, Behavior and Systematics ,geography ,geography.geographical_feature_category ,biology ,National park ,010604 marine biology & hydrobiology ,Fishes ,biology.organism_classification ,Chondrichthyes ,Fishery ,Archipelago ,Sharks ,Marine protected area - Abstract
The Revillagigedo Archipelago National Park is the largest no-take Marine Protected Area in North America and it is essential for the conservation of globally endangered marine megafauna, including cetaceans, sea birds and cartilaginous fishes. The present paper reports the occurrence of 28 chondrichthyan species, including 19 sharks, seven batoids and two chimaeras in the Revillagigedo Archipelago, comprising eight new records and a brief revision of confirmed species to date.
- Published
- 2020
9. First records of the seven‐gilled <scp> Notorynchus cepedianus </scp> and six‐gilled <scp> Hexanchus griseus </scp> sharks (Chondrichthyes: Hexanchiformes: Hexanchidae) found in the Galápagos Marine Reserve
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Alan Turchik, Jonatha Giddens, Paulina Sepa, Salome Buglass, David A. Ebert, Fernando Rivera, Shannon Nagy, and Katherine L.C. Bell
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0106 biological sciences ,food.ingredient ,biology ,Range (biology) ,010604 marine biology & hydrobiology ,Marine reserve ,Hexanchiformes ,Aquatic Science ,biology.organism_classification ,010603 evolutionary biology ,01 natural sciences ,Chondrichthyes ,Fishery ,food ,Habitat ,Hexanchus ,Notorynchus ,Ecology, Evolution, Behavior and Systematics ,Apex predator - Abstract
This study reports the first records of cowsharks (Hexanchidae) in the Galapagos Islands, in particular Notorynchus cepedianus and Hexanchus griseus, observed between depths of 210 and 418 m on footage from free-falling autonomous deep-ocean cameras. These sightings provide new information on the habitat preferences and range distribution for N. cepedianus and the first records of H. griseus in Ecuadorian waters. The findings support the formulation of regional conservation strategies for these large apex predator species and highlight the limited biological knowledge of Galapagos' deep-water ecosystems.
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- 2020
10. The multiscale architecture of tessellated cartilage and its relation to function
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Mason N. Dean, Aravind Kumar Jayasankar, and Ronald Seidel
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Mammals ,0106 biological sciences ,biology ,010604 marine biology & hydrobiology ,Cartilage ,Aquatic Science ,biology.organism_classification ,010603 evolutionary biology ,01 natural sciences ,Chondrichthyes ,Skeletal tissue ,Structure-Activity Relationship ,medicine.anatomical_structure ,Evolutionary biology ,Sharks ,medicine ,Animals ,Ecology, Evolution, Behavior and Systematics ,Function (biology) - Abstract
When describing the architecture and ultrastructure of animal skeletons, introductory biology, anatomy and histology textbooks typically focus on the few bone and cartilage types prevalent in humans. In reality, cartilage and bone are far more diverse in the animal kingdom, particularly within fishes (Chondrichthyes and Actinopterygii), where cartilage and bone types are characterized by features that are anomalous or even pathological in human skeletons. This review discusses the curious and complex architectures of shark and ray tessellated cartilage, highlighting similarities and differences with their mammalian skeletal tissue counterparts. By synthesizing older anatomical literature with recent high-resolution structural and materials characterization work, this review frames emerging pictures of form-function relationships in this tissue and of the evolution and true diversity of cartilage and bone.
- Published
- 2020
11. Growth trajectories of prenatal embryos of the deep‐sea shark <scp> Chlamydoselachus anguineus </scp> (Chondrichthyes)
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Sho Tanaka, Faviel A. López-Romero, Claudia Klimpfinger, and Jürgen Kriwet
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Male ,0106 biological sciences ,Embryo, Nonmammalian ,frilled shark ,Ontogeny ,Embryonic Development ,Zoology ,Aquatic Science ,010603 evolutionary biology ,01 natural sciences ,Deep sea ,Total Body Length ,Regular Paper ,Animals ,jaw development ,geometric morphometrics ,development ,Phylogeny ,Ecology, Evolution, Behavior and Systematics ,Morphometrics ,Sex Characteristics ,biology ,010604 marine biology & hydrobiology ,Regular Papers ,biology.organism_classification ,Chondrichthyes ,Sexual dimorphism ,ontogeny ,Sharks ,Chlamydoselachus anguineus ,Female ,Allometry ,Ovoviviparity - Abstract
Chlamydoselachus anguineus, Garman 1884, commonly called the frilled shark, is a deep‐sea shark species occurring up to depths of 1300 m. It is assumed to represent an ancient morphotype of sharks (e.g., terminal mouth opening, more than five gill slits) and thus is often considered to represent plesiomorphic traits for sharks. Therefore, its early ontogenetic developmental traits are important for understanding the evolution of its particular phenotype. Here, we established six stages for prenatal embryos and used linear measurements and geometric morphometrics to analyse changes in shape and size as well as their timing during different embryonic stages. Our results show a change in head shape and a relocation of the mouth opening at a late stage of development. We also detected a negative allometric growth of the head and especially the eye compared to the rest of the body and a sexual dimorphism in total body length, which differs from the known data for adults. A multivariate analysis of covariance shows a significant interaction of shape related to the logarithm of centroid size and developmental stage. Geometric morphometrics results indicate that the head shape changes as a covariate of body size while not accounting for differences between sexes. The growth pattern of stages 32 and 33 indicates a shift in head shape, thus highlighting the moment in development when the jaws start to elongate anteriorly to finally achieve the adult condition of terminal mouth opening rather than retaining the early embryonic subterminal position as is typical for sharks. Thus, the antero‐terminal mouth opening of the frilled shark has to be considered a derived feature.
- Published
- 2020
12. On the presence of the Eastern Pacific Black Ghostshark Hydrolagus melanophasma (Chondrichthyes: Chimaeridae) in northern Chile, with notes on its distribution in the Eastern Pacific
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Juan Francisco Araya, Pablo Reyes, and Mathias Hüne
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0106 biological sciences ,Dissostichus ,biology ,business.industry ,010604 marine biology & hydrobiology ,Distribution (economics) ,Gyrocotyle ,04 agricultural and veterinary sciences ,Aquatic Science ,Oceanography ,biology.organism_classification ,01 natural sciences ,Chondrichthyes ,Deep water ,Fishery ,Bycatch ,Geography ,Hydrolagus melanophasma ,040102 fisheries ,0401 agriculture, forestry, and fisheries ,business ,Chimaeridae - Abstract
The Eastern Pacific Black Ghostshark Hydrolagus melanophasma (James et al. Zootaxa 2218:59–68, 2009) is a recently described deep water holocephalan found along the Eastern Pacific and so far known from a few records. Here we present new records for this species based on specimens collected as bycatch in the Chilean Seabass, Dissostichus eleginoides Smith, 1898 fishery at a depth of 1800 m off Taltal (25°S), northern Chile. This is the first record of Hydrolagus melanophasma in northern Chile, and its second occurrence in the southeastern Pacific, filling a gap in the distribution of the species and confirming its presence in the southeastern Pacific. We also report the first record of a Gyrocotyle species as parasite in this species.
- Published
- 2020
13. Morphological deformities in the pelvic fin and clasper in specimens of Potamotrygon marquesi (Chondrichthyes: Myliobatiformes: Potamotrygoninae)
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André Luis da Silva Casas and João Paulo C. B. Da Silva
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0106 biological sciences ,Myliobatiformes ,Potamotrygonidae ,Potamotrygon ,Pelvic girdle ,biology ,010604 marine biology & hydrobiology ,04 agricultural and veterinary sciences ,Anatomy ,Aquatic Science ,Clasper ,biology.organism_classification ,01 natural sciences ,Skeleton (computer programming) ,Chondrichthyes ,stomatognathic system ,040102 fisheries ,Deformity ,medicine ,0401 agriculture, forestry, and fisheries ,medicine.symptom - Abstract
We report deformities in the pelvic fin and clasper skeleton in specimens of Potamotrygon marquesi from Acre, Northwestern Brazil. The malformations involve skeletal deformities in the pelvic girdle, right clasper skeleton, and severe muscular and skeletal deformities in the left or right pelvic fin and clasper, including the loss of all of its terminal components. Descriptions of malformations dealing with elasmobranchs are extensive in the literature and are important for future studies dealing with their probable causes. Nevertheless, although the reasons of these deformities are herein possibly linked to malformation (as a result of stress or chemical contaminants) or predation, the anomalies in the muscular and skeletal components of the pelvic fin and clasper are described in detail and compared to a non‐deformed specimen.
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- 2020
14. On the presence of the spinner shark Carcharhinus brevipinna (Müller & Henle, 1839) (Chondrichthyes: Carcharhinidae) in Maldivian waters
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F. Russo and A. De Maddalena
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Ecology ,biology ,QH301-705.5 ,spinner shark ,Zoology ,Aquatic Science ,biology.organism_classification ,Chondrichthyes ,shark ,ecotourism ,Huvadhoo Atoll ,Carcharhinus brevipinna ,Biology (General) ,Ecology, Evolution, Behavior and Systematics - Abstract
We present the first confirmed report on the presence of spinner shark, Carcharhinus brevipinna, in Maldivian waters. The species was observed in front of Kooddoo’s harbour, in Villingili pass, Northern Huvadhoo Atoll, Southern Maldives in March 2020.
- Published
- 2021
15. Elasmobranch Responses to Experimental Warming, Acidification, and Oxygen Loss—A Meta-Analysis
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Catarina Pereira Santos, Eduardo Sampaio, Beatriz P. Pereira, Maria Rita Pegado, Francisco O. Borges, Carolyn R. Wheeler, Ian A. Bouyoucos, Jodie L. Rummer, Catarina Frazão Santos, and Rui Rosa
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0106 biological sciences ,warming ,Environmental change ,batoids ,Science ,media_common.quotation_subject ,Climate change ,Ocean Engineering ,Context (language use) ,QH1-199.5 ,Aquatic Science ,Biology ,sharks ,Oceanography ,010603 evolutionary biology ,01 natural sciences ,acidification ,03 medical and health sciences ,14. Life underwater ,Chondrichthyes ,030304 developmental biology ,Water Science and Technology ,media_common ,0303 health sciences ,Global and Planetary Change ,Ecology ,Oxygen transport ,General. Including nature conservation, geographical distribution ,Hypoxia (environmental) ,Global change ,Overexploitation ,climate change ,13. Climate action ,Psychological resilience - Abstract
Despite the long evolutionary history of this group, the challenges brought by the Anthropocene have been inflicting an extensive pressure over sharks and their relatives. Overexploitation has been driving a worldwide decline in elasmobranch populations, and rapid environmental change, triggered by anthropogenic activities, may further test this group's resilience. In this context, we searched the literature for peer-reviewed studies featuring a sustained (>24 h) and controlled exposure of elasmobranch species to warming, acidification, and/or deoxygenation: three of the most pressing symptoms of change in the ocean. In a standardized comparative framework, we conducted an array of mixed-model meta-analyses (based on 368 control-treatment contrasts from 53 studies) to evaluate the effects of these factors and their combination as experimental treatments. We further compared these effects across different attributes (lineages, climates, lifestyles, reproductive modes, and life stages) and assessed the direction of impact over a comprehensive set of biological responses (survival, development, growth, aerobic metabolism, anaerobic metabolism, oxygen transport, feeding, behavior, acid-base status, thermal tolerance, hypoxia tolerance, and cell stress). Based on the present findings, warming appears as the most influential factor, with clear directional effects, namely decreasing development time and increasing aerobic metabolism, feeding, and thermal tolerance. While warming influence was pervasive across attributes, acidification effects appear to be more context-specific, with no perceivable directional trends across biological responses apart from the necessary to achieve acid-base balance. Meanwhile, despite its potential for steep impacts, deoxygenation has been the most neglected factor, with data paucity ultimately precluding sound conclusions. Likewise, the implementation of multi-factor treatments has been mostly restricted to the combination of warming and acidification, with effects approximately matching those of warming. Despite considerable progress over recent years, research regarding the impact of these drivers on elasmobranchs lags behind other taxa, with more research required to disentangle many of the observed effects. Given the current levels of extinction risk and the quick pace of global change, it is further crucial that we integrate the knowledge accumulated through different scientific approaches into a holistic perspective to better understand how this group may fare in a changing ocean.
- Published
- 2021
16. State of Shark and Ray Genomics in an Era of Extinction
- Author
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Jessica Pearce, Matthew W. Fraser, Ana M. M. Sequeira, and Parwinder Kaur
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Science ,Population ,Ocean Engineering ,Genomics ,Aquatic Science ,QH1-199.5 ,Oceanography ,sharks ,Genome ,rays ,genomics ,education ,Chondrichthyes ,Water Science and Technology ,Data deficient ,Whole genome sequencing ,Global and Planetary Change ,education.field_of_study ,Extinction ,conservation ,General. Including nature conservation, geographical distribution ,Evolutionary biology ,Threatened species ,Conservation status ,molecular science - Abstract
Chondrichthyan species (sharks, rays, skates, and chimeras) are a class of high ecological, economic, and cultural significance, and yet they are the most threatened taxa in the marine environment. The creation of reference chromosome-length genome assemblies allows for conservation genomics methods, such as population and ecological genomics, to be utilized. Despite being greatly threatened and of great importance in maintaining ecosystem function, chondrichthyan species have been repeatedly absent from conservation-based genome sequencing projects. Less than 1% of these species have a genome sequence, despite their almost 50% either threatened or Data Deficient conservation status. Most notably, there are seven orders within this class without any genome representation. In this review, we identify gaps in chondrichthyan genomic resources and demonstrate how the lack of genomic resources for this major taxonomic class is limiting the conservation of these already difficult to conserve species. We highlight other applications for chondrichthyans genomics, such as evolutionary and developmental biology. Likely, the mismatching sampling protocols and limited computational skills and communication between fields have been preventing the integration of marine and molecular sciences. Here, we propose that this field is in dire need to move forward quickly to increase protection for marine species and ecosystems through improved collaboration between marine, molecular, and computer sciences.
- Published
- 2021
17. Reducing Data Deficiencies: Preliminary Elasmobranch Fisheries Surveys in India, Identify Range Extensions and Large Proportions of Female and Juvenile Landings
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Jitesh B Solanki, Michael P. Doane, Isabel Moreno, Elizabeth A. Dinsdale, Sam R. Fellows, Shaili Johri, Isabella Livingston, Anissa Busch, and Anjani Tiwari
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0106 biological sciences ,Range (biology) ,Science ,Fishing ,India ,Ocean Engineering ,Rhinobatos annandalei ,Aquatic Science ,QH1-199.5 ,Oceanography ,sharks ,010603 evolutionary biology ,01 natural sciences ,03 medical and health sciences ,rays ,music ,030304 developmental biology ,Water Science and Technology ,Data deficient ,Sphyrna lewini ,0303 health sciences ,Global and Planetary Change ,Carcharhinus sorrah ,music.instrument ,biology ,Arabian Sea ,conservation ,General. Including nature conservation, geographical distribution ,biology.organism_classification ,Chondrichthyes ,Fishery ,Geography ,fisheries ,Carcharhinus amboinensis - Abstract
Chondrichthyes, an ancient and diverse class of vertebrates, are crucial to the health of marine ecosystems. Excessive demand for chondrichthyan products has increased fishing pressure, threatening ∼30% of species with extinction in recent decades. India is the second-largest shark landing nation globally and the province of Gujarat, is the largest contributor to its shark exports. Despite their significant contribution to global fish supplies, chondrichthyan fisheries in Gujarat remain understudied and many species, data deficient, posing challenges to the conservation of remaining populations in the region. Here, we report results from taxonomic assessment of elasmobranchs at four key landing sites in Gujarat. We identified thirty-one species of sharks and rays with a significant bias toward capture of females and juveniles by fisheries. Our data indicate the presence of nursery areas for species such as Sphyrna lewini and Rhynchobatus laevis in the neritic areas off Gujarat. Further, we discovered extensions of the current distribution range for three species -Torpedo sinuspersici, Carcharhinus sorrah, and Rhinobatos punctifer. Taxonomic identities for a subset of species were confirmed using genomic analyses conducted with portable DNA sequencing tools. We present assessments for six data deficient species in the region – Rhinobatos annandalei, Rhinoptera jayakari, Maculabatis bineeshi, Pateobatis bleekeri, T. sinuspersici, and Carcharhinus amboinensis. Our investigation underscores species with urgent conservation needs and reduces data deficiencies. These data will inform and pivot future scientific and conservation efforts to protect remaining populations of some of the most vulnerable Chondrichthyes in the Arabian Seas Region.
- Published
- 2021
18. Feeding together: a global diet analysis of twenty-three species of chondrichthyes on a feeding ground area
- Author
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Cristian Battagliotti, Federico Cortés, Mauro Belleggia, and Jorge Horacio Colonello
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0106 biological sciences ,biology ,010604 marine biology & hydrobiology ,media_common.quotation_subject ,Zoology ,Aquatic animal ,Aquatic Science ,biology.organism_classification ,010603 evolutionary biology ,01 natural sciences ,Chondrichthyes ,Crustacean ,Competition (biology) ,Predation ,Predator ,Shellfish ,Trophic level ,media_common - Abstract
A global analysis of the diet of chondrichthyes (23 species) was conducted during one bottom-trawl research cruise in the region where the highest catches of skates occurred off southwestern Atlantic. The diet was quantified by calculating the percentage frequency of occurrence of each prey. The influence of variables total length, sex, maturity stage, predator species, morphtype (sharks, skates, batoids), and depth on the diet was evaluated by fitting generalized linear models. The diet composition of chondrichthyes consisted mainly of crustaceans, polychaetes, and fish. The study region constituted a feeding ground for the majority of chondrichthyans species analyzed. The diet of chondrichthyes exhibited inter-specific differences sorted into three major trophic guilds and global ontogenetic shift. The consumption of crustaceans and polychaetes decreases with the total length of the chondrichthyes, whereas the consumption of fish increases as the predator grew in size. In addition, prey size of fish and crabs increased with increasing body size of predator, but large chondrichthyes also continued to feed on relatively small crabs. Trophic partitioning and ontogenetic diet shifts may act synergistically, favoring the coexistence of at least 23 species of chondrichthyes at all stages of their life histories, limiting the direct competition for food.
- Published
- 2019
19. Southernmost record of the white shark Carcharodon carcharias (Chondrichthyes: Lamnidae) in the Mexican Pacific
- Author
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Edgar Becerril Garcia, Edgar Hoyos Padilla, David Petatan, and Felipe Galvan Magana
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0106 biological sciences ,food.ingredient ,White (horse) ,biology ,010604 marine biology & hydrobiology ,Aquatic Science ,Oceanography ,biology.organism_classification ,010603 evolutionary biology ,01 natural sciences ,Chondrichthyes ,Carcharodon ,Carcharias ,Fishery ,Bycatch ,food ,Geography ,Lamnidae ,Juvenile - Abstract
This study reports the first record of a white shark Carcharodon carcharias off the tropical coast of Nayarit and the southernmost record in the Mexican Pacific. The specimen was a juvenile female accidentally caught by artisanal fisheries in the locality of Playa Novillero, Nayarit. Oceanographic conditions at the time of capture were also recorded, with the aim of improving the knowledge on the ecology of this vulnerable and protected species.
- Published
- 2019
20. Effects of on-deck holding conditions and air exposure on post-release behaviours of sharks revealed by a remote operated vehicle
- Author
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Jane E. Williamson, Timothy M. Smith, Vincent Raoult, and Troy F. Gaston
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0106 biological sciences ,biology ,Range (biology) ,Trawling ,010604 marine biology & hydrobiology ,Cephaloscyllium laticeps ,Aquatic Science ,biology.organism_classification ,010603 evolutionary biology ,01 natural sciences ,Chondrichthyes ,Discards ,Fishery ,Demersal fish ,Squalus megalops ,Spurdog ,human activities ,Ecology, Evolution, Behavior and Systematics - Abstract
While post-release mortality estimates have been conducted on a range of shark species, the short-term sub-lethal effects of capture, handling and release are poorly known and have been mostly investigated in controlled conditions. In addition, the widely accepted notion that immediate post-release active swimming is an indicator of shark condition has never been tested. This study assessed the effects of deck exposure by analysing post-release behaviour of two species of shark, the draughtboard ( Cephaloscyllium laticeps) and the piked spurdog ( Squalus megalops ) in-situ using a remote-operated-vehicle and in a replicated experiment in controlled conditions. In total, 67 sharks were caught with demersal fish trawls and commercial longlines and subjected to different deck exposures and release environments. Tailbeat rates of deck-exposed sharks were significantly lower than the control sharks, but this effect differed between in-situ and experimental environments. Results indicate that capture has species-specific effects, that post-release effects may last longer than 5 min, and that controlled experiments may not be reliable indicators of post-release effects. Immediate post-release swimming was not a good predictor of post-release behaviour, suggesting capture and release fisheries may have significant sub-lethal effects on some species of shark, and that limiting capture or handling time may reduce post-release effects.
- Published
- 2019
21. Study of Dimensional and Morphological Characteristics of Erythrocytes in Some Black Sea Fish of Different Evolution Position and Ecological Specialization
- Author
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Yu. A. Silkin, V. N. Chernyaeva, V. E. Vasilets, and E. N. Silkina
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0106 biological sciences ,Teleostei ,biology ,010604 marine biology & hydrobiology ,Cartilaginous fish ,Zoology ,04 agricultural and veterinary sciences ,Aquatic Science ,biology.organism_classification ,01 natural sciences ,Chondrichthyes ,medicine.anatomical_structure ,040102 fisheries ,medicine ,0401 agriculture, forestry, and fisheries ,Shape index ,%22">Fish ,Black sea ,General Agricultural and Biological Sciences ,Nucleus - Abstract
A comparative analysis of the morphometric parameters of erythrocytes in two species of cartilage (Chondrichthyes) and five species of teleosts (Teleostei) Black Sea fish of different natural mobility was carried out. The volume, area, and shape index of the cell and nucleus, the specific surface and useful volume of the cell, and the nuclear-cytoplasmic ratio are calculated based on the linear dimensions of the cell and the nucleus. It has been shown that the studied cartilaginous fish (rays) had larger erythrocytes compared with the teleosts: the linear dimensions are 2–3 times larger, and the volume is 7–30 times larger. In actively swimming teleosts, the volume of erythrocytes and their nuclei is smaller than those of slow-moving species (2–3 times and 5–9 times, respectively). The revealed differences in the erythrocytes’ morphometric characteristics of cartilaginous and teleosts are considered to reflect the direction of the evolutionary process towards increasing the energy potential of the circulatory system of the “younger” fast-swimming teleosts.
- Published
- 2019
22. Stable-isotope analysis reveals the importance of soft-bodied prey in the diet of lesser spotted dogfish Scyliorhinus canicula
- Author
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Anne Marie Power, Conor Graham, Alina M. Wieczorek, and Patricia Browne
- Subjects
0106 biological sciences ,Carbon Isotopes ,Nitrogen Isotopes ,010604 marine biology & hydrobiology ,Zoology ,Bayes Theorem ,Scyliorhinus canicula ,Feeding Behavior ,Aquatic Science ,Biology ,biology.organism_classification ,010603 evolutionary biology ,01 natural sciences ,Chondrichthyes ,Gastrointestinal Contents ,Diet ,Predation ,Predatory fish ,Spotted dogfish ,Dogfish ,Animals ,Predator ,Ecology, Evolution, Behavior and Systematics ,Trophic level ,Isotope analysis - Abstract
This study examines the diet of lesser spotted dogfish Scyliorhinus canicula, one of the most ubiquitous predators of European coastal waters. This species is of increasing ecological significance as other large predatory fish decline as it has known interactions with fisheries. Scyliorhinus canicula diet was investigated in Irish coastal waters during June and July 2014 using both stomach-content analysis and δ13 C and δ15 N stable-isotope ratios. Prey contribution to the diet from dual stable-isotope data was estimated using Bayesian mixing models. It was found that only stable-isotope analysis provided a time-integrated picture of the diet of S. canicula and allowed for a new estimation of their trophic position. Trophic positions from stomach-content analysis within the present study and previous studies were found to be higher than revealed by isotopes. Stomach-content analysis could not reveal the importance of soft-bodied animals in the diet of these fish, however this approach remains a valuable tool to understand the potential prey spectrum in advance of isotope analysis and allows for a better resolution down to species level. The results highlight a greater variety in the diet of this important predator and the benefit of taking a multidisciplinary approach in dietary studies.
- Published
- 2018
23. Using historical and citizen science data to improve knowledge about the occurrence of the elusive sandbar shark Carcharhinus plumbeus (Chondrichthyes – Carcharhinidae) in the Adriatic Sea
- Author
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Ilija Ćetković, Patrick L. Jambura, Jürgen Kriwet, and Julia Türtscher
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Environmental Engineering ,Sandbar shark ,biology ,Endangered species ,Neonates ,Aquatic Science ,Oceanography ,biology.organism_classification ,Chondrichthyes ,Parturition ,Fishery ,Mediterranean sea ,Geography ,Elasmobranchii ,Carcharhinus ,Threatened species ,Mediterranean Sea ,IUCN Red List ,Estuaries ,Ecology, Evolution, Behavior and Systematics ,Migration - Abstract
The Mediterranean Sea is an extinction hotspot for sharks, skates, and rays, with at least half of all species being threatened. The sandbar shark Carcharhinus plumbeus is among the most threatened species and is declared endangered (EN) in the Mediterranean according to the IUCN Red List of Threatened Species. The Adriatic Sea was previously proposed to be an important nursery area for this species based on sporadic sightings of neonates and juveniles. However, this species is generally considered to be rare in this region, and reports of its presence are scarce. Here, we present new records for the sandbar shark in the Adriatic Sea and review spatial and temporal data accumulated from literature, museum specimens, and citizen science initiatives in an attempt to assess the distribution and seasonality of this species. The majority of the records were from neonate and juvenile sandbar sharks, and three hotspots for their occurrence could be identified: (1) the Emilia-Romagna region, (2) the Veneto region, and (3) the Gulf of Trieste. Our data indicate a high concentration of sandbar sharks around the delta of the Po river, emphasising the need for scientific surveys in this confined area in order to confirm a possible nursery ground. Data collected by citizen science initiatives reveal that this species is still present in the Adriatic Sea and might be more abundant than previously thought, underlining the potential of citizen science as a valuable tool to monitor the distribution of rare and endangered species.
- Published
- 2021
24. First observation of a Hydrolagus melanophasma (Chondrichthyes, Chimaeriformes, Holocephali) aggregation with egg cases extruding from a female
- Author
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David A. Ebert, Alan M. Friedlander, Jonatha Giddens, Pelayo Salinas-de-León, Alan Turchik, and Brad Henning
- Subjects
Geography ,biology ,Hydrolagus melanophasma ,Zoology ,Aquatic Science ,Oceanography ,biology.organism_classification ,Chondrichthyes ,Ecology, Evolution, Behavior and Systematics ,Holocephali - Published
- 2020
25. Parturition time for the Blacktip shark, Carcharhinus limbatus (Carcharhiniformes: Carcharhinidae), in Southwestern Atlantic
- Author
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Jones Santander-Neto, Leandro Yokota, and Thiago Silveira de Meneses
- Subjects
0106 biological sciences ,Nursery ,Stock assessment ,Berçário ,Fishing ,Reproductive biology ,Biologia reprodutiva ,Aquatic Science ,Biology ,010603 evolutionary biology ,01 natural sciences ,Blacktip shark ,Abundance (ecology) ,Carcharhiniformes ,Chondrichthyes ,Ecology, Evolution, Behavior and Systematics ,Época de parto ,010604 marine biology & hydrobiology ,biology.organism_classification ,Fishery ,Birth time ,QL1-991 ,Carcharhinus ,Pesca ,Animal Science and Zoology ,Fisheries management ,Zoology - Abstract
The determination of the period of parturition and identification of nursery areas are fundamental for the management and conservation of a fishing resource. Through combination of monthly abundance, length measurements, and development time of embryos we inferred about parturition time of the Blacktip sharks, Carcharhinus limbatus, from Southwestern Atlantic. Specimens of C. limbatus were caught from 2002 and 2008 by artisanal fleets from three different locations along the Brazilian coast using gillnets (mesh width ranging between 30 and 120 mm between opposite knots and operating from 9 to 120 m in depth), handlines (19 to 140 m depth) and longlines (6 to 90 m depth). Through a comparative analysis of fisheries landing data collected, we have verified neonatal (< 90 cm) catch peaks at specific times of the year in different locations and, matching with birth prediction of embryos, propose that C. limbatuspresents a well-defined parturition time in late spring-early summer in Southwestern Atlantic. Moreover, we indicate supposed nursery grounds for the species along the Brazilian coast. This information will be crucial for stock assessments of the species and may serve as a basis for determining fisheries management measures. Resumo A determinação do período de parto e identificação de áreas de berçário são fundamentais para o manejo e conservação da espécie. Através da combinação de abundância mensal, comprimentos e tempo de desenvolvimento de embriões nós inferimos sobre a época de parto do tubarão galha preta, Carcharhinus limbatus, no Sudoeste Atlântico. Espécimes de C. limbatus foram capturados entre 2002 e 2008 por frotas artesanais de três locais diferentes ao longo da costa brasileira usando redes de emalhar (largura de malha variando entre 30 e 120 mm entre nós opostos e operando de 9 a 120 m de profundidade), linhas de mão (19 a 140 m de profundidade) e espinhel (6 a 90 m de profundidade). Através de análise comparativa de dados de desembarque pesqueiro, verificamos picos de captura de neonatos (< 90 cm) em períodos específicos do ano em diferentes localidades e, combinando com a previsão de nascimento de embriões, propomos que C. limbatus apresenta um período de parto bem definido no final da primavera e início do verão no Sudoeste do Atlântico. Além disto, nós indicamos prováveis áreas de berçário ao longo da costa brasileira. Estas informações serão cruciais para avaliações de estoque da espécie e poderão servir de base para determinação de medidas de manejo de pescarias.
- Published
- 2020
26. Records of morphological abnormalities in the Brazilian electric ray Narcine brasiliensis (Olfers, 1831) (Chondrichthyes: Narcinidae) in the southwestern Atlantic
- Author
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Matheus Marcos Rotundo, Teodoro Vaske-Júnior, Gustavo Cardoso Stabile, Fernanda A. Rolim, Universidade Estadual Paulista (Unesp), and UNISANTA
- Subjects
0106 biological sciences ,High concentration ,Narcinidae ,Anophthalmia ,Narcine ,Torpediniformes ,Fins not adherent ,010604 marine biology & hydrobiology ,Anatomy ,Aquatic Science ,Biology ,Oceanography ,biology.organism_classification ,medicine.disease ,010603 evolutionary biology ,01 natural sciences ,Chondrichthyes ,eye diseases ,Left eye ,Embryonic development ,medicine ,Ecology, Evolution, Behavior and Systematics ,Brazilian electric ray - Abstract
Made available in DSpace on 2020-12-12T01:26:20Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-08-01 This study provides the first record of external morphological deformities in Chondrichthyes of the family Narcinidae. We report here abnormalities in two individuals of Narcine brasiliensis (Olfers, 1831), in which one of them had its pectoral fins not fused with the head and the other presented anophthalmia, with the left eye absent. Possible causes, including the high concentration of pollutants in the region, are briefly discussed. Institute of Biosciences São Paulo State University UNESP Institute of Biosciences Coastal Campus São Paulo State University UNESP Zoological Collection of University of Santa Cecília UNISANTA Institute of Biosciences São Paulo State University UNESP Institute of Biosciences Coastal Campus São Paulo State University UNESP
- Published
- 2020
27. Using Local Ecological Knowledge of Fishers to Reconstruct Abundance Trends of Elasmobranch Populations in the Strait of Sicily
- Author
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Manfredi Di Lorenzo, Andrea Simonetti, Francesco Colloca, and Virginia Carrozzi
- Subjects
0106 biological sciences ,010504 meteorology & atmospheric sciences ,lcsh:QH1-199.5 ,Population ,Ocean Engineering ,Mustelus asterias ,Aquatic Science ,lcsh:General. Including nature conservation, geographical distribution ,Oceanography ,01 natural sciences ,Demersal zone ,Abundance (ecology) ,sharks and batoids ,Mediterranean Sea ,14. Life underwater ,Squalidae ,education ,lcsh:Science ,Relative species abundance ,Chondrichthyes ,fisheries sustainability ,0105 earth and related environmental sciences ,Water Science and Technology ,Global and Planetary Change ,education.field_of_study ,Overfishing ,biology ,Ecology ,010604 marine biology & hydrobiology ,local ecological knowledge ,biology.organism_classification ,Centrophoridae ,Geography ,lcsh:Q - Abstract
Fishers “local ecological knowledge” (LEK) can be used to reconstruct long-term trends of species that are at very low biomass due to overfishing. In this study, we used historical memories of Sicilian fishers to understand their perception of change in abundance of cartilaginous fish in the Strait of Sicily over the last decades. We conducted interviews with 27 retired fishers from Mazara del Vallo harbor (SW Sicily) working in demersal fisheries, using a pre-defined questionnaire with a series of open and fixed questions related to the abundance of sharks and rays. The questionnaire included specific questions about the trends they perceived in catch or by-catch of cartilaginous fish abundance between the 1940s and 2000s compared to the present. Information was gathered for 18 species, including Carcharhinidae, mesopredatory demersal sharks (Squalidae, Hexanchidae, Centrophoridae, Oxynotidae, Triakidae, Scyliorhinidae, and Squatinidae) and batoids. Overall shark catches were perceived to have diminished since the early 1940s: about 95% of fishers reported the decline of commercially important species (e.g., Mustelus spp.) and indicated species that could have been depleted or locally extinct (e.g., Squatina spp., Sphyrna lewini, Mustelus asterias, etc.). Our study shows that LEK of fishers can be beneficial for reconstructing long-term population trends of exploited species when traditional standard data on fisheries catch or species relative abundance from surveys is limited or only available for recent periods. The results obtained clearly indicate the rapid and alarming decline of elasmobranchs in the Strait of Sicily highlighting the need for urgent conservation measures to be adopted.
- Published
- 2020
28. Ecological and biological factors associated to mercury accumulation in batoids (Chondrichthyes: Batoidea) from northeastern Brazil
- Author
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Wanderley Rodrigues Bastos, Luiz Drude de Lacerda, Vicente Vieira Faria, Júlia Nunes Rabelo, Guelson Batista da Silva, Victor Lacerda Moura, Carlos Eduardo de Rezende, and Moises Fernandes Bezerra
- Subjects
0106 biological sciences ,Food Chain ,chemistry.chemical_element ,010501 environmental sciences ,Aquatic Science ,Oceanography ,01 natural sciences ,chemistry.chemical_compound ,Biological Factors ,Stingray ,Animals ,Humans ,Fatores biológicos ,Methylmercury ,0105 earth and related environmental sciences ,Trophic level ,biology ,Ecology ,010604 marine biology & hydrobiology ,Biodiversidade ,Fishes ,Mercury ,Methylmercury Compounds ,biology.organism_classification ,Pollution ,Chondrichthyes ,Ecologia ,Mercury (element) ,chemistry ,Bioaccumulation ,Batoidea ,Gymnura micrura ,Brazil ,Water Pollutants, Chemical ,Environmental Monitoring - Abstract
The present study aims to understand how ecological and biological factors affect the Hg levels in stingrays occurring in the Northeastern Brazilian coast. Total mercury (Hg), methylmercury (MeHg) and stable isotope (δ13C and δ15N) analyses were performed in five species. Hypanus americanus and Gymnura micrura showed the highest total Hg concentrations (300 and 176 ng.g−1, respectively). Hypanus guttatus exhibited a significant correlation between total Hg and size. Both species of the genus Hypanus presented the highest percentage of MeHg, around 100%, whereas the other species showed median percentages below 50%. The δ13C and δ15N signatures suggest that all studied species present the same foraging habitat but different trophic positions. Trophic position and animal size were the main factors influencing total Hg and MeHg concentrations in batoid species. The genus Hypanus, present in the Brazilian fish markets, showed concentrations above the accepted limits for human consumption.
- Published
- 2020
29. Polymorphism in Conservative Structures? The Scapulocoracoids in Skates Genus Psammobatis (Chondrichthyes, Arhynchobatidae) and the Validity of P. parvacauda
- Author
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D. M. Vazquez, J. M. Díaz de Astarloa, Mariano González-Castro, Ezequiel Mabragaña, and V. Gabbanelli
- Subjects
synonymization ,0106 biological sciences ,lcsh:QH1-199.5 ,010504 meteorology & atmospheric sciences ,Rajiformes ,scapulocoracoids ,SYNONYMIZATION ,Ocean Engineering ,lcsh:General. Including nature conservation, geographical distribution ,Aquatic Science ,Oceanography ,01 natural sciences ,INTRASPECIFIC POLYMORPHISM ,purl.org/becyt/ford/1 [https] ,Arhynchobatidae ,P. PARVACAUDA ,lcsh:Science ,Psammobatis ,purl.org/becyt/ford/1.6 [https] ,0105 earth and related environmental sciences ,Water Science and Technology ,intraspecific polymorphism ,Global and Planetary Change ,SCAPULOCORACOIDS ,biology ,010604 marine biology & hydrobiology ,biology.organism_classification ,Chondrichthyes ,PSAMMOBATIS ,P. parvacauda ,lcsh:Q ,RAJIFORMES ,Humanities - Abstract
Skeletal structures, especially the claspers, neurocrania, and scapulocoracoids have been widely used to characterize and describe new species of elasmobranchs. Intra and interspecific variation of scapulocoracoids in 3 species of Psammobatis (n = 94) from the Southwest Atlantic Ocean were analyzed to assess its utility as a diagnostic character in skates. Moreover, based on scapulocoracoids and body morphometric analyses, the validity of Psammobatis parvacauda McEachran, 1983 was evaluated. A remarkable sexual dimorphism in scapulocoracoids was observed in all species in accordance with original descriptions, which was also evident in the principal component (PCA) and Discriminant Analyses. The number and arrangement of post-dorsal and post-ventral fenestra were highly variable at intra-specific level, in contrast with original descriptions. Particularly, one of the morphotypes observed in females of P. normani was identical to the one reported in P. parvacauda. Results showed intraspecific variation in this structure, as was previously observed in Sympterygia species. Therefore, this structure should not be used as a diagnostic character in skates, at least for these genera. Regarding body morphometry the PCA showed that P. parvacauda grouped with P. normani females and the cross-validated analysis showed that P. parvacauda was classified in the group of P. normani females. P. parvacauda is only known from its original description (one female) and a likely second specimen, but our analyses revealed a lack of diagnostic characteristics. Based on observations and measurements of the holotype of P. parvacauda, and comparisons with congenerics, P. normani is regarded a senior synonym of P. parvacauda. Fil: Mabragaña, Ezequiel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina Fil: González Castro, Mariano. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina Fil: Gabbanelli, Valeria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina Fil: Vazquez, Diego Martin. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina Fil: Díaz de Astarloa, Juan Martín. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina
- Published
- 2020
30. Feeding habits of the cockfish, Callorhinchus callorynchus (Holocephali: Callorhinchidae) from off northern Argentina
- Author
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Jorge Martin Roman, Santiago Aldo Barbini, Melisa A. Chierichetti, and Lorena Beatriz Scenna
- Subjects
0106 biological sciences ,Cambios ontogenéticos ,Zoology ,Ontogenetic shifts ,Aquatic Science ,Body size ,010603 evolutionary biology ,01 natural sciences ,Predation ,Trophic level ,purl.org/becyt/ford/1 [https] ,Abundance (ecology) ,Condrictios ,Atlántico Sudoccidental ,purl.org/becyt/ford/1.6 [https] ,Chondrichthyes ,Ecology, Evolution, Behavior and Systematics ,biology ,Nivel trófico ,Callorhinchidae ,Callorhinchus callorynchus ,04 agricultural and veterinary sciences ,biology.organism_classification ,Holocephali ,Diet ,QL1-991 ,Southwest Atlantic ,040102 fisheries ,0401 agriculture, forestry, and fisheries ,Animal Science and Zoology ,Dieta - Abstract
Los hábitos alimentarios de Callorhinchus callorynchus fueron investigados en las aguas costeras del norte de Argentina. Se evaluó el efecto del tamaño del cuerpo, la temporada y la región sobre la composición de la dieta de las hembras mediante un enfoque de modelado de múltiples hipótesis. Callorhinchus callorynchus se alimentó principalmente de bivalvos (55,61% PSIRI), seguido de cangrejos brachyuras (10,62% PSIRI) y de isópodos (10,13% PSIRI). Las hembras de C. callorynchus presentaron cambios en la dieta con incremento del tamaño del cuerpo, la temporada y la región. Además, esta especie es capaz de consumir bivalvos de mayor tamaño a medida que incrementa el tamaño del cuerpo. El nivel trófico fue calculado en 3,15, caracterizando a esta especie como un consumidor secundario. Concluimos que C. callorynchus presentó un comportamiento de triturador de presas duras, principalmente bivalvos, cangrejos y gasterópodos. Las hembras de esta especie cambian su dieta con el incremento del tamaño del cuerpo y en respuesta a cambios temporales y regionales en la abundancia y distribución de sus presas. The feeding habits of Callorhinchus callorynchus were investigated in coastal waters off northern Argentina. The effect of body size, seasons and regions was evaluated on female diet composition using a multiple-hypothesis modelling approach. Callorhinchus callorynchus fed mainly on bivalves (55.61% PSIRI), followed by brachyuran crabs (10.62% PSIRI) and isopods (10.13% PSIRI). Callorhinchus callorynchus females showed changes in the diet composition with increasing body size and also between seasons and regions. Further, this species is able to consume larger bivalves as it grows. Trophic level was 3.15, characterizing it as a secondary consumer. We conclude that C. callorynchus showed a behavior of crushing hard prey, mainly on bivalves, brachyuran, gastropods and anomuran crabs. Females of this species shift their diet with increasing body size and in response to seasonal and regional changes in prey abundance or distribution. Fil: Roman, Jorge Martin. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina Fil: Chierichetti, Melisa Antonela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina Fil: Barbini, Santiago Aldo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina Fil: Scenna, Lorena Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina
- Published
- 2020
31. First record of a single-clasper specimen of Pseudobatos percellens (Elasmobranchii: Rhinopristiformes: Rhinobatidae) from the Caribbean Sea, Venezuela
- Author
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Lorem del Valle González-González and Nicolás Ehemann
- Subjects
0106 biological sciences ,Pseudobatos ,biology ,deformity ,010604 marine biology & hydrobiology ,Zoology ,Aquatic Science ,Clasper ,biology.organism_classification ,010603 evolutionary biology ,01 natural sciences ,reproduction ,guitarfish ,Geography ,Elasmobranchii ,batoid fish ,Chondrichthyes - Abstract
Documented cases of abnormalities in elasmobranchs worldwide are more often reported for sharks than their close relatives, the skates and rays. This report confirms the occurrence of a chola guitarfish, Pseudobatos percellens (Walbaum, 1792), caught off Margarita Island, Venezuela, showing morphological abnormalities on the right side of the body, including the absence of one clasper. This is the first record of an anomalous single-clasper case in the Caribbean Sea region.
- Published
- 2018
32. First report of four deep-sea chondrichthyans (Elasmobranchii and Holocephali) from Andaman waters, India with an updated checklist from the region
- Author
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K. V. Akhilesh, K. K. Bineesh, Ravi Ranjan Kumar, Purnima Rajan, and S. Venu
- Subjects
Andaman waters ,0106 biological sciences ,Bramble shark ,deep-sea ,biology ,Echinorhinus ,010604 marine biology & hydrobiology ,Heptranchias perlo ,Bluntnose sixgill shark ,Sicklefin chimaera ,India ,Aquatic Science ,biology.organism_classification ,010603 evolutionary biology ,01 natural sciences ,Holocephali ,Fishery ,Geography ,Elasmobranchii ,new record ,Hexanchus ,Chondrichthyes ,morphometry - Abstract
This paper confirms the new distributional records of four rare deep-water chondrichthyans viz. sharpnose sevengill shark, Heptranchias perlo (Bonnaterre, 1788); bluntnose sixgill shark, Hexanchus griseus (Bonnaterre, 1788); bramble shark, Echinorhinus brucus (Bonnaterre, 1788); and sicklefin chimaera, Neoharriotta pinnata (Schnakenbeck, 1931) from the Andaman waters in the Indian EEZ. The above-mentioned four fish species have not been reported earlier from this region. More exploratory surveys in the region are essential to understand the diversity and distribution pattern which is essential for critical management actions. An updated checklist of chondrichthyans known from Andaman and Nicobar waters of India is also presented.
- Published
- 2018
33. Spatial variability of Chondrichthyes in the northern Mediterranean
- Author
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Maria Cristina Follesa, Francisca Salmerón Jiménez, Igor Isajlović, Alessandro Cau, Panagiota Peristeraki, Chiara Manfredi, Francesco Colloca, Cristina Porcu, Fabrizio Serena, Walter Zupa, Pierluigi Carbonara, Letizia Sion, Mirko Djurovic, Andrea Bellodi, Antonello Mulas, Angélique Jadaud, Angelo Cau, Martina Francesca Marongiu, Sergio Ramírez-Amaro, Ioannis Thasitis, and Rita Cannas
- Subjects
0106 biological sciences ,Mediterranean climate ,Fishing ,bottom trawl surveys ,SH1-691 ,mediterranean ,abundancia ,Aquatic Science ,Mediterranean ,Oceanography ,010603 evolutionary biology ,01 natural sciences ,Demersal zone ,lcsh:Aquaculture. Fisheries. Angling ,Carcharhiniformes ,Aquaculture. Fisheries. Angling ,distribution ,14. Life underwater ,Chondrichthyes ,fish ,abundance ,campañas de pesca experimental de arrastre ,lcsh:SH1-691 ,geography.geographical_feature_category ,biology ,Continental shelf ,010604 marine biology & hydrobiology ,Scyliorhinus canicula ,distribución ,mar Mediterráneo ,biology.organism_classification ,Fishery ,Geography ,Galeus melastomus ,chondrichthyes - Abstract
Thanks to the availability of the MEDITS survey data, a standardized picture of the occurrence and abundance of demersal Chondrichthyes in the northern Mediterranean has been obtained. During the spring-summer period between 2012 and 2015, 41 Chondrichthyes, including 18 sharks (5 orders and 11 families), 22 batoids (3 orders and 4 families) and 1 chimaera, were detected from several geographical sub-areas (GSAs) established by the General Fisheries Commission for the Mediterranean. Batoids had a preferential distribution on the continental shelf (10-200 m depth), while shark species were more frequent on the slope (200-800 m depth). Only three species, the Carcharhiniformes Galeus melastomus and Scyliorhinus canicula and the Torpediniformes Torpedo marmorata were caught in all GSAs studied. On the continental shelf, the Rajidae family was the most abundant, being represented in primis by Raja clavata and then by R. miraletus, R. polystigma and R. asterias. The slope was characterized by the prevalence of G. melastomus in all GSAs, followed by S. canicula, E. spinax and Squalus blainville. Areas under higher fishing pressure, such as the Adriatic Sea and the Spanish coast (with the exception of the Balearic Islands), show a low abundance of chondrichthyans, but other areas with a high level of fishing pressure, such as southwestern Sicily, show a high abundance, suggesting that other environmental drivers work together with fishing pressure to shape their distribution. Results of generalized additive models highlighted that depth is one of the most important environmental drivers influencing the distribution of both batoid and shark species, although temperature also showed a significant influence on their distribution. The approach explored in this work shows the possibility of producing maps modelling the distribution of demersal chondrichthyans in the Mediterranean that are useful for the management and conservation of these species at a regional scale. However, because of the vulnerability of these species to fishing exploitation, fishing pressure should be further incorporated in these models in addition to these environmental drivers. Gracias a la disponibilidad de los datos de campañas de pesca experimental MEDITS, se ha realizado una imagen estandarizada de la presencia y abundancia de Chondrichthyes demersales en el norte del Mediterráneo. Durante el período primavera-verano entre 2012 y 2015, se detectaron 41 Chondrichthyes, incluidos 18 tiburones (5 órdenes y 11 familias), 22 batoides (3 órdenes y 4 familias) y 1 quimera, de varias Subáreas Geográficas (GSA) establecidas por la Comisión General de Pesca para el Mediterráneo en la zona. Los batoides tuvieron una distribución preferencial en la plataforma continental (10-200 m de profundidad), mientras que las especies de tiburones fueron más frecuentes en la ladera (200-800 m de profundidad). Solo tres especies, Carcharhiniformes Galeus melastomus, Scyliorhinus canicula y Torpediniformes Torpedo marmorata fueron capturadas en todos los GSA estudiados. En la plataforma continental, la familia Rajidae fue la más abundante, representada en primer lugar por Raja clavata y luego por R. miraletus, R. polystigma y R. asterias. La pendiente se caracterizó por la prevalencia de G. melastomus en todos los GSA, seguido de S. canicula, E. spinax y Squalus blainville. Las áreas bajo mayor presión de pesca, como el Mar Adriático y la costa española (con la excepción de las Islas Baleares), registran una baja abundancia de condricthianos, pero otras áreas con un alto nivel de presión de pesca, como el suroeste de Sicilia, presentan una gran abundancia de estas especies. Sugiere que otros impulsores ambientales trabajen juntos con la presión pesquera para dar forma a su distribución. Los resultados de los modelos aditivos generalizados resaltaron que la profundidad es uno de los factores ambientales más importantes que influyen en la distribución de las especies de batoides y tiburones, aunque la temperatura también mostró una influencia significativa en su distribución. El enfoque explorado en este trabajo muestra la posibilidad de producir mapas que modelen la distribución de los condrictios demersales en el Mediterráneo, útiles para el manejo y la conservación de estas especies a escala regional. Sin embargo, teniendo en cuenta la vulnerabilidad de estas especies a la explotación pesquera, la presión pesquera debería incorporarse a estos modelos, además de estos factores ambientales.
- Published
- 2019
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34. Preliminary insights into the spatial ecology and movement patterns of a regionally critically endangered skate (Rostroraja alba) associated with a marine protected area
- Author
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Joffrey Baeyaert, Jorge M.S. Gonçalves, Inês Sousa, and Karim Erzini
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0106 biological sciences ,Survival ,Physiology ,Conservation ,Aquatic Science ,Biology ,Oceanography ,01 natural sciences ,Rajidae ,Critically endangered ,Skate ,Chondrichthyes ,Migration ,Thornback ray ,Ecology ,010604 marine biology & hydrobiology ,Diel ,North-Sea ,04 agricultural and veterinary sciences ,biology.organism_classification ,Fish ,Rajiformes ,040102 fisheries ,Spatial ecology ,0401 agriculture, forestry, and fisheries ,Marine protected area - Abstract
The implementation of spatial protection measures is currently a priority in batoid species' conservation strategies, but their spatial ecology remains largely unknown. We provide some preliminary insights into the movement patterns of the white skate (Rostroraja alba), a batoid classified as Critically Endangered in European waters. Three individuals (two females: one mature, one immature and one immature male) were monitored with acoustic telemetry in a marine protected area (Portugal). The mature female remained present in the study area throughout the whole monitoring period (20 months). Residency analyses revealed this specimen spent more than 70% of the time within this coastal marine park. The immature female and the immature male were only detected during three and four months, respectively. Whether the uncovered movement patterns are common within the population remains unclear, but the present study provides useful information to better plan future research on the movement ecology of a rather unstudied species. Fundacao para a Ciencia e a TecnologiaPortuguese Foundation for Science and Technology [CCMAR/Multi/04326/2013] LIFE-BIOMARES project [LIFE06 NAT/P/000192] Project Buffer ERA-Net BiodivERsA [ANR-12-EBID-0006] CCMAR - Centre of Marine Sciences [CCMAR/BI/0004/2018]
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- 2019
35. Redescription of the bigeye chimaera, Hydrolagus macrophthalmus de Buen, 1959 (Chondrichthyes: Chimaeriformes), with a genetic characterization of the species
- Author
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Matthew Jew, David A. Ebert, Kristin Walovich, Kimberly L. Quaranta, and Jenny M. Kemper
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0106 biological sciences ,Macrophthalmus ,biology ,Light spot ,Hydrolagus ,010604 marine biology & hydrobiology ,Biodiversity ,Zoology ,Aquatic Science ,Oceanography ,biology.organism_classification ,010603 evolutionary biology ,01 natural sciences ,Chondrichthyes ,Dorsal fin ,Sympatric speciation ,Chimera (mythology) ,Ecology, Evolution, Behavior and Systematics - Abstract
Hydrolagus macrophthalmus de Buen, 1959 is a little known chimaerid species from the southeastern Pacific Ocean. At the time of its description, it was the only chimaeroid species known from the region; however, there now are four other Hydrolagus species known from the area. Hydrolagus macrophthalmus is distinct from other species in the area based on the following characters: an undulated second dorsal fin with peaks on the anterior and posterior regions, a long curved first dorsal fin spine that extends past the origin of the second dorsal fin when laid flat, and uniform dark brown color with a light spot on middle of the second dorsal fin that extends onto the body below it. Genetic sequencing of the NADH2 gene was used to distinguish H. macrophthalmus from other known species in the region. This species is herein re-described and compared to four sympatric species: H. alphus, H. melanophasma, H. mccoskeri, and H. trolli. The redescription of this species will improve identification and aid in the taxonomic resolution of Southeastern Pacific Ocean chimaeras. A key to species of Hydrolagus in the Southeastern Pacific Ocean is provided.
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- 2018
36. First record of the deep-water shark Etmopterus spinax (Chondrichthyes: Etmopteridae) from the southern Baltic Sea (Pomeranian Bay)
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Angelika Linowska, Klaudia Górecka, Sławomir Keszka, Remigiusz Panicz, Ewa Sobecka, and Beata Więcaszek
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0106 biological sciences ,Atmospheric Science ,education.field_of_study ,biology ,010604 marine biology & hydrobiology ,Fauna ,Population ,Ocean Engineering ,Aquatic Science ,Oceanography ,biology.organism_classification ,010603 evolutionary biology ,01 natural sciences ,Chondrichthyes ,Fishery ,lcsh:Oceanography ,Geography ,Mediterranean sea ,Etmopteridae ,Etmopterus ,Pomeranian ,lcsh:GC1-1581 ,education ,Bay - Abstract
Summary: Etmopterus spinax is a deep-sea shark species that inhabits the northeast Atlantic and the western Mediterranean Sea. Skagerrak and Kattegat are reported to be part of the distribution of the species, but it has never been noted in the southern Baltic. Lacking any commercial value and commonly discarded in trawl and longline fisheries, E. spinax has been poorly studied. We reported on the first record of one specimen of E. spinax caught in the Pomeranian Bay on October 13, 2016 at a depth of 10 m. It was a female measuring 42.7 cm in total length. The morphological examination of the specimen was supported with COI barcode analysis, whereas species assignment to the population of origin was conducted based on a control region (CR) sequence of mtDNA. COI and CR sequence searches against GeneBank confirmed its identity as E. spinax and revealed that the specimen shared identical haplotypes with fish from populations in the Azores, Rockall Trough, and west of Ireland in the northeast Atlantic. The stomach contents, parasitic fauna, and hepatosomatic index of the individual were also examined. Only one L3 larval Anisakis simplex nematode specimen was collected from the stomach lumen of the shark. The specimen could have arrived in the Pomeranian Bay along with an inflow from the North Sea. In December 2014, a strong Major Baltic Inflow brought large amounts of water into the Baltic Sea, followed by some inflows of moderate intensity. Keywords: Etmopterus spinax, Anisakis simplex, Pomeranian Bay, Southern Baltic Sea, Inflow from the North Sea
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- 2018
37. Holocephalan (Chondrichthyes) dental plates with hypermineralized dentine as a substitute for missing teeth through developmental plasticity
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Chris Healy, Charlie J. Underwood, Moya Meredith Smith, Brett Clark, Esther Manzanares, and Zerina Johanson
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0106 biological sciences ,Aquatic Science ,010603 evolutionary biology ,01 natural sciences ,dentition ,dentine ,stomatognathic system ,Species Specificity ,Chimaera ,Harriotta ,cps ,Animals ,development ,Ecology, Evolution, Behavior and Systematics ,biology ,Dentition ,Hydrolagus ,whitlockin ,010604 marine biology & hydrobiology ,Anatomy ,Chimaeroidei ,biology.organism_classification ,Chondrichthyes ,Holocephali ,stomatognathic diseases ,Odontoblast ,Dentin ,Sharks ,Developmental plasticity ,Tooth - Abstract
All extant holocephalans (Chimaeroidei) have lost the ability to make individual teeth, as tooth germs are neither part of the embryonic development of the dental plates, nor of their continuous growth. Instead, a hypermineralized dentine with a unique mineral, whitlockin, is specifically distributed within a dentine framework into structures that give the dental plates their distinctive, species-specific morphology. Control of the regulation of this distribution must be cellular, with a dental epithelium initiating the first outer dentine, and via contact with ectomesenchymal tissue as the only embryonic cell type that can make dentine.\ud Chimaeroids have three pairs of dental plates within their mouth, two in the upper jaw and one in the lower. In the genera Chimaera, Hydrolagus and Harriotta, the morphology and distribution of this whitlockin within each dental plate differs both between different plates in the same species and between species. Whitlockin structures include ovoids, rods and tritoral pads, with substantial developmental changes between these. For example, rods appear before the ovoids, and result from a change in the surrounding trabecular dentine. In Harriotta, ovoids form separately from the tritoral pads, but also contribute to tritor development, while in Chimaera and Hydrolagus, tritoral\ud This article is protected by copyright. All rights reserved.\ud pads develop from rods that later are perforated to accommodate the vasculature. Nevertheless, the position of these structures, secreted by the specialized odontoblasts (whitloblasts), appears highly regulated in all three species. These distinct morphologies are established at the aboral margin of the dental plate, with proposed involvement of the outer dentine. We observe that this outer layer forms into serially added lingual ridges, occurring on the anterior plate only. We propose that positional, structural specificity must be contained within the ectomesenchymal populations, as stem cells below the dental epithelium, and a coincidental occurrence of each lingual, serial ridge with the whitlockin structures that contribute to the wear resistant oral surface.
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- 2019
38. Reproductive biology, multiple paternity and polyandry of the bull shark Carcharhinus leucas
- Author
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Thomas Poirout, Hélène Magalon, Agathe Pirog, Sébastien Jaquemet, Ecologie marine tropicale dans les Océans Pacifique et Indien (ENTROPIE [Réunion]), Centre National de la Recherche Scientifique (CNRS)-Université de La Réunion (UR)-Institut de Recherche pour le Développement (IRD), Laboratoire d'Excellence CORAIL (LabEX CORAIL), Institut de Recherche pour le Développement (IRD)-Université des Antilles et de la Guyane (UAG)-École des hautes études en sciences sociales (EHESS)-École pratique des hautes études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de La Réunion (UR)-Université de la Polynésie Française (UPF)-Université de la Nouvelle-Calédonie (UNC)-Institut d'écologie et environnement-Université des Antilles (UA), and The study was financially supported by CHARC programme (Feder Fund convention 2011 Presage N° 33,021) and ECORECORUN program (DEAL BOP113).
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0106 biological sciences ,Litter (animal) ,Male ,Carcharhinidae ,polyandry ,Zoology ,Paternity ,Gestation period ,Aquatic Science ,Bull shark ,010603 evolutionary biology ,01 natural sciences ,Sexual Behavior, Animal ,Reproductive biology ,Animals ,14. Life underwater ,Mating ,Indian Ocean ,Chondrichthyes ,Ecology, Evolution, Behavior and Systematics ,Leucas ,reproductive and urinary physiology ,life history traits ,biology ,010604 marine biology & hydrobiology ,Reproduction ,[SDV.BA]Life Sciences [q-bio]/Animal biology ,biology.organism_classification ,Carcharhinus ,Sharks ,Female ,Western Indian Ocean ,Seasons ,Reunion ,reproductive cycle ,Microsatellite Repeats - Abstract
International audience; To improve understanding of bull shark Carcharhinus leucas reproductive biology, we analysed reproductive traits from 118 bull sharks caught along Reunion Island coasts (Western Indian Ocean), including 16 gravid females. Specific microsatellite loci were used to investigate the frequency of multiple paternity. Males and females reached maturity at c. 234 cm and 257 cm total length (LT), respectively, and litter sizes ranged from 5 to 14 embryos. Analysis of the 16 litters collected in various months of the year indicated that parturition occurs between October and December, with a size at birth c. 60–80 cm LT and that the gestation period is probably c. 12 months. Assuming a 1 year resting period and a period of sperm storage (4–5 months) between mating (in June–September) and fertilisation, the reproductive cycle of bull sharks at Reunion Island would be biennial. At least 56.25% of the litters investigated were polyandrous, sired by 2–5 males. Several males that each sired several litters conceived during the same or distinct mating seasons were detected, suggesting both a seasonal aggregation of sharks to mate and some male fidelity to mating site. Altogether, these findings provide valuable information for both shark risk management and conservation of the species in the Western Indian Ocean.
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- 2019
39. First record of Leucoraja circularis (Chondrichthyes: Rajidae) in the Syrian marine waters (Eastern Mediterranean)
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Hasan Alkusairy and Adib Saad
- Subjects
0106 biological sciences ,Immature male ,First specimen ,Syrian coast ,Ecology ,biology ,Morphometric ,lcsh:QH1-199.5 ,010607 zoology ,Sandy skate ,Zoology ,Aquatic Science ,lcsh:General. Including nature conservation, geographical distribution ,Oceanography ,biology.organism_classification ,010603 evolutionary biology ,01 natural sciences ,Chondrichthyes ,Leucoraja circularis ,Eastern mediterranean ,First record ,Skate ,Ecology, Evolution, Behavior and Systematics - Abstract
Sandy Skate, Leucoraja circularis (Couch, 1838), is recorded for first time from the Syrian marine waters. Two specimens of L. circularis were caught by bottom trawl at depth about 120 m on 20 February 2017, the first specimen was an immature female and the second an immature male; they measured 580 mm and 628 mm total length, and weighed 880 g and 1240 g, respectively. This capture represents the first documented record of the species in the Syrian marine waters (Eastern Mediterranean) so further investigations should be made to detect new species along the Syrian coast.
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- 2018
40. Sexually dimorphic body proportions in the catshark genus Scyliorhinus (Chondrichthyes: Carcharhiniformes: Scyliorhinidae)
- Author
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Karla D. A. Soares
- Subjects
Male ,0106 biological sciences ,Zoology ,Aquatic Science ,010603 evolutionary biology ,01 natural sciences ,Genus ,Carcharhiniformes ,Mediterranean Sea ,Animals ,Atlantic Ocean ,Ecology, Evolution, Behavior and Systematics ,Morphometrics ,Analysis of Variance ,Sex Characteristics ,Body proportions ,biology ,010604 marine biology & hydrobiology ,Fishes ,biology.organism_classification ,Chondrichthyes ,Catshark ,Sexual dimorphism ,Scyliorhinus ,Sharks ,Female - Abstract
Intersexual differences in morphometrics were investigated in five species of the catshark genus Scyliorhinus. ANCOVA was used to test 59 measurements, considering capture location and total length as covariates. In all examined species, pelvic-anal distances and pelvic-fin inner margin lengths were greater in males than in females, representing a clear pattern for the genus.
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- 2019
41. Avoiding being dragged away: finding egg cases ofSchroederichthys bivius(Chondrichthyes: Scyliorhinidae) associated with benthic invertebrates
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Laura Schejter, Ezequiel Mabragaña, M. Belleggia, and Diego Martin Vazquez
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0106 biological sciences ,biology ,010604 marine biology & hydrobiology ,Schroederichthys bivius ,Zoology ,Anatomy ,Aquatic Science ,biology.organism_classification ,010603 evolutionary biology ,01 natural sciences ,Chondrichthyes ,Catshark ,Benthic zone ,Oviparity ,Ecology, Evolution, Behavior and Systematics ,Invertebrate - Abstract
Egg cases of the narrowmouthed catshark Schroederichthys bivius were recorded entangled with sponges, corals and tubeworms at different sites in the south-west Atlantic Ocean. This work sheds light on the importance of benthic invertebrates in the life cycle of oviparous chondrichthyan species.
- Published
- 2017
42. Biological observations on the broadfin shark Lamiopsis temminckii (Carcharhiniformes: Carcharhinidae)
- Author
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Thakurdas, Shoba Joe Kizhakudan, K. V. Akhilesh, and G. B. Purushottama
- Subjects
0106 biological sciences ,Litter (animal) ,biology ,010604 marine biology & hydrobiology ,Zoology ,Aquatic Science ,biology.organism_classification ,010603 evolutionary biology ,01 natural sciences ,Chondrichthyes ,Crustacean ,Lamiopsis temminckii ,Predation ,Bycatch ,Carcharhiniformes ,Ecology, Evolution, Behavior and Systematics - Abstract
Biological information was collected from 214 individuals of the broadfin shark Lamiopsis temminckii measuring 418 to 1782 mm total length, LT . Size at maturity (L50 ) for females and males was estimated at 1430 and 1368 mm LT , respectively, while mature and gravid females were observed from 1350 mm LT with litter sizes 2-8 and size at birth 418-650 mm LT . Analysis of stomach contents revealed a variety of prey, primarily crustaceans (54·0%), teleosts (42·7%) and cephalopods.
- Published
- 2017
43. Population biology of the little gulper shark Centrophorus uyato in Lebanese waters
- Author
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Myriam Lteif, B. Seret, Marion Verdoit-Jarraya, Gaby Khalaf, Philippe Lenfant, and Rita Mouawad
- Subjects
0106 biological sciences ,biology ,010604 marine biology & hydrobiology ,04 agricultural and veterinary sciences ,Aquatic Science ,biology.organism_classification ,Spatial distribution ,01 natural sciences ,Chondrichthyes ,Centrophoridae ,Centrophorus uyato ,Bycatch ,Fishery ,040102 fisheries ,0401 agriculture, forestry, and fisheries ,14. Life underwater ,Allometry ,Relative species abundance ,Ecology, Evolution, Behavior and Systematics ,Sex ratio - Abstract
A total of 38 individuals of the heavily exploited little gulper shark Centrophorus uyato were collected from Lebanese coastal waters using bottom longlines and trammel nets of different meshes at depths ranging from 115 to 600 m between May 2013 and February 2014. Their total lengths were between 45 and 94 cm and their total mass was from 870 to 6700 g. The sex ratio was not significantly different from 1:1, with 20 males and 18 females, but bathymetric sexual segregation occurred. Catch per net setting (CNS) was used as a relative abundance index to detect spatial distribution; trammel nets showed largest CNS ranging from 4·9 to 5·45 kg per unit effort in the north and south, at depths from 120 to 200 m, during spring and summer. The mass-length relationships demonstrated negative allometric growth (b
- Published
- 2017
44. Length–weight relationships of six elasmobranch species captured at the artisanal fishery of Margarita Island, Venezuela
- Author
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Nicolás Ehemann and Lorem del Valle González-González
- Subjects
0106 biological sciences ,Myliobatis freminvillei ,biology ,Length weight ,010604 marine biology & hydrobiology ,04 agricultural and veterinary sciences ,Aquatic Science ,biology.organism_classification ,01 natural sciences ,Chondrichthyes ,Fishery ,Mustelus higmani ,040102 fisheries ,0401 agriculture, forestry, and fisheries - Abstract
This study reports the length–weight relationship (LWR) for five batoid and one shark species, all frequently captured by the artisanal commercial fishery on Margarita Island (10o44’–11o10’N and 63o46’–64o13’W), Venezuela. In 2013, elasmobranchs captured by the artisanal fleet (using bottom gillnets 200–400 m in length with 5–8 inch mesh size) were identified, sized, weighed and sexed. The value of a ranged from 0.0006 to 0.0351, meanwhile the b value ranged from 2.84 (for pooled Myliobatis freminvillei) to 3.39 (male Mustelus higmani), with r² ranging from 0.920 to 0.991. Differences in LWR due to sex were observed for three elasmobranch species. This study offers LWRs separate for males and females, also for species for which LWRs already exist and thus new knowledge is gained through the estimate presented here.
- Published
- 2018
45. Dermal denticle variations on a newborn Roughskin Dogfish Centroscymnus owstonii (Chondrichthyes: Somniosidae) captured off northeastern Brazil with notes on ontogenetic differentiation
- Author
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Getulio Rincon, Rodrigo C. Mazzoleni, Rosangela Lessa, Patricia Charvet, Rafael Mota, and Mateus Ferreira de Moura
- Subjects
0106 biological sciences ,010504 meteorology & atmospheric sciences ,Ecology ,biology ,Somniosidae ,010604 marine biology & hydrobiology ,Ontogeny ,Rostrum ,Zoology ,Aquatic Science ,biology.organism_classification ,01 natural sciences ,Chondrichthyes ,Birth size ,Juvenile ,Animal Science and Zoology ,Centroscymnus owstonii ,Centroscymnus owstoni ,Ecology, Evolution, Behavior and Systematics ,0105 earth and related environmental sciences - Abstract
The Roughskin Dogfish Centroscymnus owstonii is a poorly known species with eventual records along the Western South Atlantic. Different dermal denticles have been historically reported for juveniles and adults, which presupposes changes from a juvenile denticle type to an adult denticle type during growth. The present study was based on a male neonate 324 mm in total length (TL) captured with crab pots on the northeastern continental slope of Brazil, between 400–450 meters. This was considered a newborn based on its small size, very similar to previously reported large embryo dimensions and close to the expected birth size in literature. Three different dermal denticles were observed, alternating from the rostrum to the branchial slits, where a tricuspidated denticle type extended covering the rest of the posterior portion of the body. Dermal denticle types and distribution suggest that the replacement process of dermal denticles begins before birth or early after birth, undergoing at least three changes until reaching the adult dermal denticle type. These different types may be related to uterine epithelial histotroph absorption or embryo movement within the mucous environment, which would be enhanced by largely spaced denticles. The reported fragmented distribution of this species along the Brazilian coast is probably related to insufficient sampling coverage.
- Published
- 2021
46. Squalus bassisp. nov., a new long-snouted spurdog (Chondrichthyes: Squaliformes: Squalidae) from the Agulhas Bank
- Author
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M. R. de Carvalho, David A. Ebert, and S. T. de. F. L. Viana
- Subjects
0106 biological sciences ,Morphometrics ,geography ,geography.geographical_feature_category ,Continental shelf ,010607 zoology ,Zoology ,Aquatic Science ,Biology ,biology.organism_classification ,010603 evolutionary biology ,01 natural sciences ,Chondrichthyes ,Fishery ,Squaliformes ,Taxonomy (biology) ,Spurdog ,Squalidae ,Snout ,Ecology, Evolution, Behavior and Systematics - Abstract
The long-snouted African spurdog Squalus bassi sp. nov. is described based on material collected from the outer shelf and upper continental slope off South Africa and Mozambique. Squalus bassi shares with S. mitsukurii, S. montalbani, S. chloroculus, S. grahami, S. griffini, S. edmundsi, S. quasimodo and S. lobularis a large snout with prenarial length greater than distance between nostrils and upper labial furrows, dermal denticles tricuspidate and rhomboid and elevated number of vertebrae. Squalus bassi can be distinguished from all its congeners by a combination of body and fin colouration, external morphometrics, vertebral counts and shape of dermal denticles. Similar long-snouted congeners from the Indo-Pacific region, including S. montalbani, S. edmundsi and S. lalannei are compared in detail with the new species. This new species has been misidentified as the Japanese S. mitsukurii and the Mediterranean S. blainvillei due to the lack of comparative morphological analyses. The validity of the nominal species S. mitsukurii in the south-eastern Atlantic Ocean and western Indian Ocean is also clarified herein, indicating it has a more restricted geographical distribution in the North Pacific Ocean.
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- 2017
47. Reproductive aspects of the Atlantic angel sharkSquatina dumerilin the southern Caribbean Sea
- Author
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Alejandro Tagliafico, Matt K. Broadhurst, and Salomé Rangel
- Subjects
0106 biological sciences ,biology ,010604 marine biology & hydrobiology ,media_common.quotation_subject ,Zoology ,Atlantic angel shark ,Gestation period ,Aquatic Science ,Fecundity ,biology.organism_classification ,010603 evolutionary biology ,01 natural sciences ,Chondrichthyes ,Population density ,Fishery ,Sexual maturity ,Reproduction ,Ecology, Evolution, Behavior and Systematics ,Sex ratio ,media_common - Abstract
The maturity and reproduction of the Atlantic angel shark Squatina dumeril were assessed using 77 females (29·2-110·4 cm total length; LT ) and 269 males (58·7-108·2 cm LT ) harvested by artisanal gillnetters off Venezuela. The biased sex ratio implied segregation or sex-specific gear selectivity. Based on the development of the reproductive tract, 50% LT at sexual maturity (LT50 , mean ± s.e.) for females and males were estimated at 86·14 ± 0·64 and 81·55 ± 0·12 cm, respectively. Uterine fecundity ranged between one and six and with a maximum embryo size of 25·7 cm LT . Gravid females were observed from August to December, including those close to parturition and while the gestation period was not confirmed, the size of ovarian follicles among some specimens implied protraction. The low fecundity of the species supports close monitoring of catches.
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- 2017
48. Evidence for systemic age underestimation in shark and ray ageing studies
- Author
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Alastair V. Harry
- Subjects
0106 biological sciences ,education.field_of_study ,010604 marine biology & hydrobiology ,media_common.quotation_subject ,Population ,Longevity ,Common method ,Management, Monitoring, Policy and Law ,Aquatic Science ,Biology ,Oceanography ,biology.organism_classification ,010603 evolutionary biology ,01 natural sciences ,Chondrichthyes ,law.invention ,Ageing ,law ,Radiocarbon dating ,Life history ,education ,Ecology, Evolution, Behavior and Systematics ,Demography ,media_common - Abstract
Numerous studies have now demonstrated that the most common method of ageing sharks and rays, counting growth zones on calcified structures, can underestimate true age. I reviewed bomb carbon dating (n = 15) and fluorochrome chemical marking (n = 44) age validation studies to investigate the frequency and magnitude of this phenomenon. Age was likely to have been underestimated in nine of 29 genera and 30% of the 53 populations studied, including 50% of those validated using bomb carbon dating. Length and age were strongly significant predictors of occurrence, with age typically underestimated in larger and older individuals. These characteristics suggest age underestimation is likely a systemic issue associated with the current methods and structures used for ageing. Where detected using bomb carbon dating, growth zones were reliable up to 88% of asymptotic length (L∞) and 41% of maximum age (AMax). The maximum magnitude of age underestimation, ΔMax, ranged from five to 34 years, averaging 18 years across species. Current perceptions of shark and ray life histories are informed to a large extent by growth studies that assume calcified ageing structures are valid throughout life. The widespread age underestimation documented here shows this assumption is frequently violated, with potentially important consequences for conservation and management. In addition to leading to an underestimation of longevity, the apparent loss of population age-structure associated with it may unexpectedly bias growth and mortality parameters. Awareness of these biases is essential given shark and ray population assessments often rely exclusively on life history parameters derived from ageing studies.
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- 2017
49. Redescription and sexual dimorphism of Andaman leg-skateCruriraja andamanica(Chondrichthyes: Rajiformes) with comments on the zoogeography of the genusCruriraja
- Author
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Hashim Manjebrayakath, K. V. Akhilesh, V. N. Sanjeevan, M. P. Rajeeshkumar, K. S. Sumod, U. V. Parmeswaran, and Jacob Vinu
- Subjects
0106 biological sciences ,biology ,Rajiformes ,Zoology ,04 agricultural and veterinary sciences ,Aquatic Science ,biology.organism_classification ,010603 evolutionary biology ,01 natural sciences ,Chondrichthyes ,Sexual dimorphism ,Zoogeography ,Genus ,parasitic diseases ,040102 fisheries ,0401 agriculture, forestry, and fisheries ,Key (lock) ,Skate ,Cruriraja ,Ecology, Evolution, Behavior and Systematics - Abstract
This paper redescribes sexually dimorphic Cruriraja andamanica based on five juvenile (four males, one female) and four adult specimens (three males, one female) collected from Andaman waters. Morphometric comparison of the present specimens with a female specimen collected off the coast of Tanzania reveals considerable dissimilarities between them. These findings, along with the wide geographical distance between collection locations, support a need for revision of the Tanzanian specimen, which, in all probability, represents a new species in the genus. The paper also addresses zoogeography of genus Cruriraja across the world’s oceans and provides a revised key to the species.
- Published
- 2017
50. Reproductive biology of Psammobatis rutrum (Chondrichthyes: Arhynchobatidae) in south Brazil, south-west Atlantic
- Author
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Mariana F. Martins and Maria Cristina Oddone
- Subjects
0106 biological sciences ,Morphometrics ,biology ,Ecology ,010604 marine biology & hydrobiology ,Zoology ,Aquatic Science ,biology.organism_classification ,Fecundity ,010603 evolutionary biology ,01 natural sciences ,Chondrichthyes ,Reproductive biology ,Arhynchobatidae ,Vitellogenesis ,Psammobatis ,Oviparity ,Ecology, Evolution, Behavior and Systematics - Abstract
This study presents information on the reproductive biology of Psammobatis rutrum based on 55 males and 53 females obtained as by-catch from bottom trawlers off southern Brazil during July 2013 and September 2014 and includes a detailed description of the egg capsule. Total lengths (LT) ranged from 22·3 to 31·6 cm and most of the sample comprised larger individuals, although there were no sexual differences in length-frequency distributions. Significant sexual differences were found for total length-disc width, LT–body mass and LT–eviscerated body mass relationships, with females being heavier and larger. Males started to mature at 25·5 cm LT and females, at 25·9 cm LT, while LT at maturity was calculated in 26·67 and 26·81 cm, respectively. Attaining larger sizes and mass may represent a reproductive investment for females, as observed in other rajoid species. Egg bearing females were first observed over 27·1 cm LT and ovarian fecundity was 1–12 vitellogenic follicles. The egg capsules were 2·22–2·62 cm length and had attaching fibrils on both lateral sides. Microscopically, the ventral face of the egg capsule was rougher than the dorsal face.
- Published
- 2017
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