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Gül G, Yokeş MB, Demirel N. The occurrence and feeding of a critically endangered shark species, Oxynotus centrina in the Sea of Marmara. JOURNAL OF FISH BIOLOGY 2022; 101:728-735. [PMID: 35642655 DOI: 10.1111/jfb.15119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2022] [Accepted: 05/22/2022] [Indexed: 06/15/2023]
Abstract
The angular roughshark, Oxynotus centrina (Linnaeus, 1758), is a rarely encountered deep-sea demersal shark species. It is listed as "Critically Endangered" in the IUCN's regional assessment for the Mediterranean. Like other sharks and rays, the angular roughshark is subject to by-catch in demersal trawl and longline fisheries. This study contributes new knowledge on (a) its occurrence, size and sex information; and (b) its feeding ecology in the Sea of Marmara. Data were collected on total length (TL), total weight (TW) and sex from unpublished research survey reports performed intermittently from 1994 to 2020. According to the data, O. centrina was mainly recorded from the muddy sand bottom type in the southwest region of the Marmara Sea, which has higher biodiversity of macrobenthic species than other regions. Different methodological approaches were conducted to understand its feeding, such as DNA metabarcoding and isotope analysis to identify its prey spectra and assign a trophic level. Sampled specimens were full of liquid in their stomachs without any discernible visually identifiable prey items. The metabarcoding analyses were also unsuccessful in identifying any prey items. Trophic position calculation based on nitrogen isotope in muscles highlighted that O. centrina has the highest trophic position compared to the other sharks and rays in the Sea of Marmara. Although it was found mainly feeding on polychaetes and sipunculids species from previous studies, the δ15 N values made the authors cautious about the possibility of this species feeding on low trophic-level benthic invertebrates. Because the authors could not observe the presence of shark vitellus in the stomachs and could not succeed in DNA identification for prey, this study highlights high δ15 N values similar to top predators for O. centrina. The authors conclude that this species strategically feeds mainly on shark eggs to fulfil its nutritional requirements with minimum energy expenditure in line with its slow-moving behaviour and mouth morphology.
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Affiliation(s)
- Güzin Gül
- Institute of Marine Sciences and Management, Istanbul University, Istanbul, Turkey
| | | | - Nazli Demirel
- Institute of Marine Sciences and Management, Istanbul University, Istanbul, Turkey
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Gajić AA, Lelo S, Joksimović A, Pešić A, Tomanić J, Beširović H, Dragičević B. Contemporary records of the rare and critically endangered angular rough shark, Oxynotus centrina (Linnaeus, 1758), from the eastern Adriatic Sea. JOURNAL OF FISH BIOLOGY 2022; 100:329-334. [PMID: 34697815 DOI: 10.1111/jfb.14932] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Revised: 10/16/2021] [Accepted: 10/20/2021] [Indexed: 06/13/2023]
Abstract
The angular rough shark, Oxynotus centrina (Linnaeus, 1758), is a poorly known and rare bathydemersal shark inhabiting continental shelves and upper slopes with a significant lack of data and rarely published records in the Adriatic Sea in this century. In this paper, we present 20 new occurrences recorded from May 2015 to September 2021, of which 19 are in Croatian and one in Montenegrin territorial waters. Records of juveniles, subadults and adults are reported. Higher number of records off the Kornati archipelago in the central Adriatic Sea suggest that this area is of particular importance for this species. Furthermore, habitats in the Southern Adriatic might have lower density. Due to the nonsystematic research and nonprobabilistic data collection, it is difficult to establish whether the greater number of records in the continental shelf is just an ostensible phenomenon.
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Affiliation(s)
- Andrej A Gajić
- Sharklab ADRIA: Center for Marine and Freshwater Biology, In-Naxxar, Malta
- Shark Tales f/b National Geographic, Washington, District of Columbia, USA
| | - Suvad Lelo
- Sharklab ADRIA: Center for Marine and Freshwater Biology, In-Naxxar, Malta
- Faculty of Science and Mathematics, University of Sarajevo, Sarajevo, Bosnia and Herzegovina
| | | | - Ana Pešić
- Institute for Marine Biology, Kotor, Montenegro
| | | | - Hajrudin Beširović
- Sharklab ADRIA: Center for Marine and Freshwater Biology, In-Naxxar, Malta
- Faculty of Veterinary Medicine, University of Sarajevo, Sarajevo, Bosnia and Herzegovina
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Bio-Ecological Features Update on Eleven Rare Cartilaginous Fish in the Central-Western Mediterranean Sea as a Contribution for Their Conservation. Life (Basel) 2021; 11:life11090871. [PMID: 34575020 PMCID: PMC8471685 DOI: 10.3390/life11090871] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Revised: 08/19/2021] [Accepted: 08/20/2021] [Indexed: 11/18/2022] Open
Abstract
Cartilaginous fish are commonly recognized as key species in marine ecosystems for their fundamental ecological role as top predators. Nevertheless, effective management plans for cartilaginous fish are still missing, due to the lack of knowledge on their abundance, distribution or even life-history. In this regard, this paper aims at providing new information on the life-history traits, such as age, maturity, reproductive period, in addition to diet characteristics of eleven rare cartilaginous fish inhabiting the Central-Western Mediterranean Sea belonging to the orders Chimaeriformes (Chimaera monstrosa), Hexanchiformes (Heptranchias perlo and Hexanchus griseus), Myliobatiformes (Aetomylaeus bovinus and Myliobatis aquila), Rajiformes (Dipturus nidarosiensis and Leucoraja circularis), Squaliformes (Centrophorus uyato, Dalatias licha and Oxynotus centrina) and Torpediniformes (Tetronarce nobiliana), useful for their assessment and for future management actions. Particularly, the present paper provides for the first time the age estimation of D. nidarosienis and L. circularis which were both found capable of becoming older than ten years. In addition, the present study updates the sizes of first maturity of C. uyato and D. licha, which appeared to be capable of reproducing earlier than what was previously hypothesized, representing very valuable information for a better understanding of these rare species populations status and, eventually, their conservation. On the basis of the stomach content analysis, it was possible to identify five different predator groups.
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Moyer JK, Finucci B, Riccio ML, Irschick DJ. Dental morphology and microstructure of the Prickly Dogfish Oxynotus bruniensis (Squaliformes: Oxynotidae). J Anat 2020; 237:916-932. [PMID: 32539172 DOI: 10.1111/joa.13251] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2020] [Revised: 05/19/2020] [Accepted: 05/20/2020] [Indexed: 11/25/2022] Open
Abstract
This study describes and illustrates the jaws, teeth, and tooth microstructure of the Prickly Dogfish Oxynotus bruniensis. Detailed accounts of the dental morphology of O. bruniensis are rare and have not addressed the tissue arrangement or microstructure of the teeth. These features are documented and discussed in the contexts of interspecific comparisons with other elasmobranchs and the dietary specialization of O. bruniensis. The overall tooth morphology of O. bruniensis is similar to those of other closely related members in the order Squaliformes, as is the tissue arrangement, or histotype. Oxynotus bruniensis exhibits a simplified enameloid microstructure, which we compare with previously documented enameloid microstructures of other elasmobranchs. Though subtle interspecific differences in dental characters are documented, neither overall tooth morphology nor histotype and microstructure are unique to O. bruniensis. We conclude that in the case of O. bruniensis, dietary specialization is facilitated by behavioral rather than morphological specialization.
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Affiliation(s)
- Joshua K Moyer
- Graduate Program in Organismic and Evolutionary Biology, University of Massachusetts Amherst, Amherst, MA, USA
| | - Brittany Finucci
- National Institute of Water and Atmospheric Research, Wellington, New Zealand
| | | | - Duncan J Irschick
- Graduate Program in Organismic and Evolutionary Biology, University of Massachusetts Amherst, Amherst, MA, USA.,Department of Biology, University of Massachusetts Amherst, Amherst, MA, USA
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Flammensbeck CK, Pollerspöck J, Schedel FDB, Matzke NJ, Straube N. Of teeth and trees: A fossil tip‐dating approach to infer divergence times of extinct and extant squaliform sharks. ZOOL SCR 2018. [DOI: 10.1111/zsc.12299] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
| | | | | | - Nicholas J. Matzke
- Division of Ecology, Evolution, and Genetics Research School of Biology The Australian National University Canberra Australia
- School of Biological Sciences University of Auckland Auckland New Zealand
| | - Nicolas Straube
- SNSB – Bavarian State Collection of Zoology (ZSM) Munich Germany
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Koehler L. New records of angular rough sharks Oxynotus centrina in the coastal waters of Malta, with observations on post-capture resilience and release behaviour. JOURNAL OF FISH BIOLOGY 2018; 92:2039-2044. [PMID: 29737020 DOI: 10.1111/jfb.13641] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2018] [Accepted: 04/04/2018] [Indexed: 06/08/2023]
Abstract
One male and one female angular rough sharks Oxynotus centrina were caught south-east of Malta between May and June at a depth of 60-100 m < 5 km from shore. The immature female (total length, LT 565 mm) was landed dead but the male (535 mm LT ) was found alive. This communication presents important biological observations on post-capture recovery and release behaviour of this species.
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Affiliation(s)
- L Koehler
- Sharklab- Malta, 27 "Chris", Triq Il-Kappella, Tal-Lunzjata, In-Naxxar, Salina, NXR 6031, Malta
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Finucci B, Bustamante C, Jones EG, Dunn MR. Reproductive biology and feeding habits of the prickly dogfish Oxynotus bruniensis. JOURNAL OF FISH BIOLOGY 2016; 89:2326-2344. [PMID: 27606943 DOI: 10.1111/jfb.13116] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2016] [Revised: 05/23/2016] [Accepted: 07/18/2016] [Indexed: 06/06/2023]
Abstract
The reproductive biology and diet of prickly dogfish Oxynotus bruniensis, a deep-sea elasmobranch, endemic to the outer continental and insular shelves of southern Australia and New Zealand, and caught as by-catch in demersal fisheries, are described from specimens caught in New Zealand waters. A total of 53 specimens were obtained from research surveys and commercial fisheries, including juveniles and adults ranging in size from 33·5 to 75·6 cm total length (LT ). Estimated size-at-maturity was 54·7 cm LT in males and 64·0 cm LT in females. Three gravid females (65·0, 67·5 and 71·2 cm LT ) were observed, all with eight embryos. Size-at-birth was estimated to be 25-27 cm LT . Vitellogenesis was not concurrent with embryo development. Analysis of diet from stomach contents, including DNA identification of prey using the mitochondrial genes cox1 and nadh2, revealed that O. bruniensis preys exclusively on the egg capsules of holocephalans, potentially making it the only known elasmobranch with a diet reliant solely upon other chondrichthyans. Based on spatial overlap with deep-sea fisheries, a highly specialized diet, and reproductive characteristics representative of a low productivity fish, the commercial fisheries by-catch of O. bruniensis may put this species at relatively high risk of overfishing.
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Affiliation(s)
- B Finucci
- School of Biological Sciences, Victoria University of Wellington, P. O. Box 600, Wellington, 6140, New Zealand.
| | - C Bustamante
- Molecular Fisheries Laboratory, School of Biomedical Sciences, The University of Queensland, St Lucia, QLD, 4072, Australia
| | - E G Jones
- National Institute of Water and Atmospheric Research, 41 Market Place, Auckland, 1010, New Zealand
| | - M R Dunn
- School of Biological Sciences, Victoria University of Wellington, P. O. Box 600, Wellington, 6140, New Zealand
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Kousteni V, Megalofonou P. Observations on the biological traits of the rare shark Oxynotus centrina (Chondrichthyes: Oxynotidae) in the Hellenic Seas. JOURNAL OF FISH BIOLOGY 2016; 89:1880-1888. [PMID: 27460546 DOI: 10.1111/jfb.13077] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2016] [Accepted: 06/07/2016] [Indexed: 06/06/2023]
Abstract
New records of the rare angular rough shark Oxynotus centrina from the Hellenic Seas are presented. Its occurrence is reported for the first time in the Corinthian Gulf. Some aspects of the species' biology are described and compared with previous studies.
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Affiliation(s)
- V Kousteni
- Faculty of Biology, Department of Zoology-Marine Biology, University of Athens, Panepistimiopolis, Ilisia, 15784 Athens, Greece
| | - P Megalofonou
- Faculty of Biology, Department of Zoology-Marine Biology, University of Athens, Panepistimiopolis, Ilisia, 15784 Athens, Greece
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