Squid cartilage chondroitin sulfate E (CS-E) exhibits various biological activities, including anticoagulant activities, lymphoid regulatory activities, and neuroregulatory activities Ueoka, C., ...Kaneda, N., Okazaki, I., Nadanaka, S., Muramatsu, T., and Sugahara, K. (2000) J. Biol. Chem. 275, 37407-37413. These activities are expressed through molecular interactions with specific proteins, including heparin cofactor II, selectins, CD44, chemokines, and the heparin-binding growth factor midkine. Hence, the sugar sequence information is essential for a better understanding of the CS-E functions. Previously, several novel tetrasaccharides containing the unreported 3-O-sulfated glucuronic acid (GlcA) were isolated after digestion of squid cartilage CS-E with testicular hyaluronidase. In this study, hexasaccharides were isolated to obtain more detailed sequence information, especially around the GlcA(3-O-sulfate) residue, and were characterized by fast atom bombardment mass spectrometry and 500 or 600 MHz super(1)H NMR spectroscopy. The findings demonstrate one tetrasulfated and five pentasulfated hexasaccharide sequences, five of them being novel. They were composed of three disaccharide building units of either A GlcA( beta 1-3)GalNAc(4-O-sulfate), E GlcA( beta 1-3)GalNAc(4,6-O-disulfate), K GlcA(3-O-sulfate)( beta 1-3)GalNAc(4-O-sulfate), L GlcA(3-O-sulfate)( beta 1-3)GalNAc(6-O-sulfate), or M GlcA(3-O-sulfate)( beta 1-3)GalNAc(4,6-O-disulfate), forming E-A-A, M-A-A, K-L-A, E-E-A, K-K-A, and A-M-A hexasaccharide sequences. The K-L tetrasaccharide sequence is to date unreported. The isolated sequences appear to indicate the occurrence of an unreported GlcA 3-O-sulfotransferase specific for chondroitin sulfate. The obtained sequence information will be useful for investigating the structure-function relationship and biosynthesis of CS-E.
The Greenland shark (Somniosus microcephalus), an iconic species of the Arctic Seas, grows slowly and reaches >500 centimeters (cm) in total length, suggesting a life span well beyond those of other ...vertebrates. Radiocarbon dating of eye lens nuclei from 28 female Greenland sharks (81 to 502 cm in total length) revealed a life span of at least 272 years. Only the smallest sharks (220 cm or less) showed signs of the radiocarbon bomb pulse, a time marker of the early 1960s. The age ranges of prebomb sharks (reported as midpoint and extent of the 95.4% probability range) revealed the age at sexual maturity to be at least 156 ± 22 years, and the largest animal (502 cm) to be 392 ± 120 years old. Our results show that the Greenland shark is the longest-lived vertebrate known, and they raise concerns about species conservation.
Patterns of Chondrichthyes species richness (CSR) are widely recognized as being influenced by environmental conditions. However, untangling the intricate interplay between anthropogenic impacts and ...spatial patterns of CSR remains a challenging endeavor. In this study, we evaluate the influence of thirteen human-related variables, encompassing human-induced effects and marine protected areas, on global CSR. Additionally, we explore their effects on threatened species, those declining, those utilized and traded, and those facing direct human-induced threats. Utilizing simple, multiple, and simultaneous regression models, we comprehensively investigated the relationship between human-altered variables and marine protected areas on CSR across oceanic regions. Our findings distinctly reveal a compelling convergence of human-related variables with CSR. Notably, factors such as global ocean acidification, demersal destructive practices (e.g., bottom trawling), pelagic low bycatch techniques (e.g., hook and line), and demersal non-destructive high bycatch methods (e.g., pots, traps) exhibit robust negative associations. Intriguingly, a positive association emerges with the presence of marine protected areas. Furthermore, our study underscores the profound impact of diverse human activities on CSR, significantly heightening their vulnerability to threats and imminent extinction risks. These results accentuate the critical significance of conservation strategies centered on marine protected areas, maximizing the optimized preservation of Chondrichthyes across marine ecosystems. In light of these insights, we stress the paramount role of planners and managers in mitigating direct human impacts on marine ecosystems, which is crucial for ensuring the enduring presence of Chondrichthyes across the oceans.
La Formación Irati (Cisuraliense, Kunguriense) se destaca por sus características sedimentológicas, paleontológicas y tafonómicas, importantes para conocer detalles paleoambientales y deposicionales. ...Dos miembros componen esta formación: Taquaral, el inferior, y Assitência, superior. En el miembro Taquaral, las características litológicas, las estructuras sedimentológicas y los datos paleontológicos permitieron el reconocimiento de tres facies. Las facies arenosa inferior es caracterizada por una fauna de vertebrados rica y diversificada. La segunda facies, compuesta por lutitas limosas, contiene una familia endémica de crustáceos Clarkecariidae, desconocida en cualquier otro depósito del mundo, lo que deja evidente del cuerpo de agua durante la sedimentación de esta facies. La tercera facies, conocida solo en el Estado de Paraná, es la única que alcanza condiciones intermitentes para la sedimentación de carbonatos. Los moluscos bivalvos están presentes solo en estas facies, cuya sedimentación ocurrió solo en la mitad superior de este miembro. Este trabajo presenta una síntesis del registro paleontológico del miembro Taquaral y una interpretación de los distintos ambientes deposicionales obtenida a partir de datos sedimentológicos y paleontológicos.
Ultrasound imaging can be used as an effective tool to measure the reproductive status and condition of sharks. This usually requires restraint of the subject, which is not feasible in the wild when ...the target species is of conservation concern and very large, as is the case for whale sharks. Our study invoked a behavioral response in free-swimming whale sharks that allowed snorkelers to image internal organs and structures using a submersible ultrasound scanner linked to an iPhone in an underwater housing. We were able to reliably locate and monitor the heart and other internal organs inside the body cavity, structures inside the head, and image skin and muscle in the dorsal surface of the sharks. The technique is evaluated as a means for assessing the condition and reproductive status of free-swimming whale sharks.
Abstract
In this review of the behavioural patterns of chondrichthyan fishes, we have strived to produce a comprehensive catalogue of events and states and develop standardized terminology. Hence, ...actions that are slightly different, will be pooled under inclusive titles. Those used by different investigators are included in quotations within the textual descriptions of the motor patterns. This standardized ethogram will ideally lead to an increase in inter-observer reliability, giving researchers more confidence when reading colleagues’ papers that report behaviours that appear similar to theirs despite being described for different species. The descriptions are presented under the following categories: (1) maintenance (2) courtship (3) filter feeding (4) scavenging (5) predation (6) sociality (7) aggression and (8) defence. The many actions are illustrated by line drawings and photographs in composite figures with an attempt to provide an example of each action for a chimaera, shark, and ray. The diversity of patterns is evident from this ethogram, consistent with observation that the brain-to-body mass ratios of cartilaginous fishes are greater than a third of the bird species and greater than those for some mammalian species. The major impetus for assembling this ethogram is to demonstrate the diversity of behaviours exhibited by members of the Chondrichthyes and to dispel the apocryphal belief that members of this taxon are ‘simple feeding machines’.
This study provides an updated list of fish in the Class Chondrichthyes sampled during all research projects conducted in the north-western Ionian Sea from 1985 to 2020. A total of 36 Chondrichthyes ...species belonging to 8 orders and 19 families were detected, most of them distributed over a wide depth range, between shelf and slope. For species assessed by the International Union for Conservation of Nature (IUCN), 8 species are listed as Critically Endangered, 3 as Endangered, 6 Vulnerable and 5 as Near Threatened species. The distribution of cartilaginous fish was examined exploring the historical series of MEDITS data (1995–2020. Changes in the species diversity and in their abundance with time and space were detected and some environmental and anthropogenic drivers that could have caused these changes were analysed. An increase in the presence, number of species and biomass of Chondrichthyes was detected from 1995 to 2020. The GAM analyses seem to indicate that the observed increase in species number and biomass is due to the decrease in fishing capacity and increase in salinity and temperature on the bottom. Furthermore, for the most abundant species, Galeus melastomus, an increase of biomass, size and a deeper distribution over the last 26 years were detected. Significant changes in biomass were also observed for other abundant species in the study area (Scyliorhinus canicula and Raja miraletus). The increase in biomass over time, different from several Mediterranean observations, is discussed in relation to the presence of refuge areas in the north-western Ionian Sea.
Sharks and rays are threatened by overfishing, yet we have little idea of the conservation status of the hundreds of Data Deficient species. Here, we developed an ecological trait model to predict ...the categorical conservation status of 22 Northeast Atlantic and 13 Mediterranean Sea Data Deficient sharks and rays. We first developed an explanatory cumulative link mixed model based on regionally data-sufficient species on the International Union for Conservation of Nature (IUCN) Red List of Threatened Species™ using maximum body size, median depth, and reproductive mode, then predicted the statuses of Data Deficient species. Species exclusive to the Mediterranean were 3.8 times more likely to be threatened than species exclusive to the Northeast Atlantic. Over half of Northeast Atlantic (55%, n = 12 of 22), and two-thirds of Mediterranean (62%, n = 8 of 13) Data Deficient species were predicted to be threatened. When applied to all data-sufficient species, the mean predictive accuracy was 71% and 66% for the Northeast Atlantic and Mediterranean models, respectively. Overall, Northeast Atlantic Data Deficient species are predicted to be 1.4 times more threatened than data-sufficient species proportionally (39% assessed-threatened, n = 38 of 98), whereas threat levels in the Mediterranean Sea are similarly high for both (65% assessed-threatened, n = 39 of 60 data-sufficient). With the growing availability of vertebrate trait databases, trait-based, categorical prediction of conservation status is a cost-effective approach towards incorporating Data Deficient species into unbiased (i) estimates of lineage-wide extinction rates, (ii) protected species lists, and (iii) Red List Indices, thus preventing poorly-known species from reaching extinction unnoticed.
•Northeast Atlantic and Mediterranean sharks and rays are more threatened than the global average.•One fifth of Europe's sharks and rays are Data Deficient.•Data Deficient species are equally or more threatened than evaluated in the Northeast Atlantic and Mediterranean Sea.•Categorical predictions enable Data Deficient species inclusion in conservation planning.
The verification of food authenticity and provenance is a complex task and has raised public concern in recent years due to multiple episodes of food fraud and potential risks to consumers. In this ...sense, the evaluation of multi-elemental signatures is increasingly applied to confirm and validate the site of origin of animal products. Yet, we lack understanding of its efficacy for mobile organisms such as fish. Using multi-element Total Reflection X-ray Fluorescence (TXRF) analysis of muscle of thornback ray Raja clavata we successfully identified the fishing area of individuals collected in four areas along the Portuguese Atlantic coast (Atlantic Iberian waters, Northeast Atlantic). Overall, As, Fe, Sn, V and Zn presented higher contributions to discrimination (especially Fe and Rb for neighbouring collection areas), whilst the higher concentration elements (Na, K, P, S, Ca, Cl, Br and Sr) had similar concentrations among locations. Rays captured in the two areas with higher urbanization/industrialization presented higher concentration of elements associated with anthropogenic activities (such as As, Zn, Sn and V). In terms of food safety, only 0.9% and 2.8% of the individuals surpassed the recommended thresholds values for human consumption for Hg and Cd respectively. A canonical analysis of principal components resulted in classification accuracy of thornback ray to collection site of 56.7–84.2% (depending on site), with an overall accuracy of 65.1% over c. 500 km of coast in the Northeast Atlantic.
•Elemental signatures are increasingly applied to confirm fish product provenance.•Elemental profiles accurately classified the samples for its collection site in 65.1% of the cases.•Only 2.8% of the samples surpassed the recommended thresholds values for human consumption for some elements.•TXRF analysis is a cost-effective method to evaluate commercial fish species provenance and safety.
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