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Saponins encompass a diverse group of naturally occurring glycoside molecules exhibiting amphiphilic properties and a broad range of biological activities. There is a resurgence of interest in those saponins produced by marine organisms based on their potential therapeutic benefits, application in food products and most recently their potential involvement in intra- and inter-species chemical communication. The continual advancements in liquid chromatography techniques and mass spectrometry technologies have allowed for greater detection rates, as well as improved isolation and elucidation of saponins. These factors have significantly contributed to the expansion in the catalogue of known saponin structures isolated from marine invertebrates; however, there currently exists no specific chemical library resource to accelerate the discovery process. In this study, a Marine Animal Saponin Database (MASD v1.0) has been developed to serve as a valuable chemical repository for known marine saponin-related data, including chemical formula, molecular mass and biological origin of nearly 1000 secondary metabolites associated with saponins produced by marine invertebrates. We demonstrate its application with an exemplar asteroid extract (Acanthaster cf. solaris, also known as crown-of-thorns starfish; COTS), identifying saponins from the MASD v1.0 that have been previously reported from COTS, as well as 21 saponins isolated from multiple other related asteroid species. This database will help facilitate future research endeavours, aiding researchers in exploring the vast chemical diversity of saponins produced by marine organisms and providing ecological insights, and the realisation of their potential for various applications, including as pharmaceuticals. [ABSTRACT FROM AUTHOR]

In this study, microplastics (MPs) contaminations in Kodek Bay, North Lombok, West Nusa Tenggara, Indonesia, were investigated from water, sediment, and marine animal samples to evaluate the impact of waste discharges from anthropogenic activities and river run-off around the bay. The samples were collected from three site categories: port, residential area, and aquaculture floating net cages. Water quality in each site was also observed. Three marine animals with different feeding regimes were selected to assess MPs contamination, including pompano (Trachinotus blochii), crab (Ocypode kuhlii), and oyster (Crassostrea sp.). A series of extraction protocols followed by stereomicroscope observation were conducted to identify the MPs' abundance, form type, and color. Next, the MPs polymer type was characterized using Fourier Transform Infra Red (FT-IR) at a frequency range 4000–400 cm-1 resolution 4.0 with Bruker Alpha II spectrometer. The results showed no significant difference (P < 0.5) in MPs abundance in water (15.75–20 part.L−1) and sediment (10.25–12.3 part.kgDW−1) samples between the sites as well as between marine animals (23.20–27.03 part.ind−1). Various MPs types and color proportions were observed from water and sediment from different sampling locations and marine animal body parts. The MPs form types found include fragment (6–58%), film (7–49%), fiber (2–25%), and pellet (20–78%), while based on the MPs particle colors, the proportion were black (14–78%), yellow (7–33%), blue (2–25%), red (8–30%) and green (2–30%). Analysis of functional groups and polymers from water, sediments, and marine animal samples indicated the presence of PS (Polystyrene) and PE (Polyethylene). The study results indicated widespread MP contamination in the Kodek Bay area. The results serve as a scientific-based recommendation for policymaking to further prevent MPs contamination in the area. [ABSTRACT FROM AUTHOR]

Foundation species, such as seagrasses, trees, and corals, form the biotic basis for many ecosystems. They engineer local habitats and can support many faunal species through trophic (e.g. providing feeding grounds) or non‐trophic (e.g. providing predation shelters and spawning grounds) mechanisms. How the supporting effects of foundation species on fauna change across multiple trophic levels remains poorly understood. We investigated how a foundational seagrass supported faunal species at different trophic levels, using a series of comparative surveys, diet analyses, and field experiments. We found that seagrasses substantially enhanced marine fauna across all but one of four trophic levels. Primary, secondary, and top consumers were significantly more abundant, whilst tertiary consumers were similarly or less abundant in seagrass beds than on unvegetated mudflats. Importantly, seagrasses supported fauna of different trophic levels via different trophic or non‐trophic mechanisms; seagrasses provided mainly feeding, refuging and feeding, feeding, and spawning grounds for primary, secondary, tertiary, and top consumers, respectively. Our work reveals that seagrasses support fauna from primary to top trophic levels via different trophic and non‐trophic mechanisms. Our findings highlight that protecting and restoring seagrasses is critical to enhancing fauna across multiple trophic levels and can inform conservation strategies targeted for fauna at different trophic levels. Our study can help stimulate future studies from other ecosystems to test how foundation species affect fauna across different trophic levels. Read the free Plain Language Summary for this article on the Journal blog. [ABSTRACT FROM AUTHOR]

Predicting and mitigating the impacts of anthropogenic ocean noise on marine animals is hindered by a lack of information on hearing in these species. We established a catch-and-release program to temporarily hold adolescent minke whales (Balaenoptera acutorostrata) for hearing tests during their summer migration. In 2023, two minke whales provided measures of the auditory brainstem response and data on the frequency range of their hearing. Results show that minke whales are sensitive to sound frequencies as high as 45 to 90 kilohertz. These tests provide information on the types of anthropogenic noise that could affect minke whales and potentially, other related baleen whale species. [ABSTRACT FROM AUTHOR]

Ocean plastic pollution is a global concern, exacerbated by the distinctive physiochemical characteristics of nanoplastics (NPs), making it crucial to study the impacts on marine animals, particularly fish, given their ecological and economic importance. Both trophic transfer and waterborne exposure are potential modes of NP entry into seafood for human consumption Although the majority of studies have focused on in-vitro impacts of NP exposure in fish, in-vivo methods can offer a more holistic understanding of these impacts. This study investigates polystyrene NP transfer to Coryphaena hippurus (mahi-mahi) larvae, a widely consumed fish and significant marine predator, during the early life stage. Brachionus plicatilis (rotifers) were exposed to NPs, and subsequently fed to C. hippurus larvae, with exposure duration ranging from 24 to 96 h. Significant NP transfer was observed via the food chain, varying with exposure duration. A depuration study over 72 h, simulating intermittent NP exposure, revealed substantial NP excretion but also notable retention in the larvae. Biodistribution analysis indicated that most NPs accumulated in the gut, with a significant portion remaining post-depuration and some translocating to other body areas containing vital organs like the heart, liver, and gall bladder. Despite no significant effects on body length and eye diameter during this short study period, histopathological analysis revealed intestinal tissue damage in the larvae. Overall, this study provides valuable insight into the trophic transfer of NPs in marine food webs, emphasizing the need for further research on ecological impacts and highlighting the importance of addressing NP contamination to protect marine ecosystems and food safety. [ABSTRACT FROM AUTHOR]

Historical data are often overlooked in risk assessments and recovery plans for marine animals, resulting in the "shifting baselines." Historical ecological studies demonstrate the "surprising" extent to which contemporary assumptions misrepresent premodern baselines. The Florida manatee, a subspecies of the West Indian manatee found primarily in Florida, USA, faces several existential threats, but risk assessments and recovery targets for the species are hindered by poor understanding of historical baselines. We conducted systematic and opportunistic reviews of archaeological and historical records of manatee occurrence in Florida, USA. Our data reveal that manatee populations in Florida were very small in the Precolonial and Colonial Periods, possibly representing infrequent in-migration from the Caribbean during favorable climate conditions. Manatees expanded in number and range across the Florida peninsula during the Territorial/Early Statehood and Early Modern Periods, first northward on the Atlantic Coast and later along the coast of the Gulf of Mexico. These expansions track increasing human populations, associated anthropogenic landscape alterations, and social and policy changes. Historical ecology is critical for "shaping a better Anthropocene" for humans and manatees in Florida. [ABSTRACT FROM AUTHOR]

Simple Summary: Type III secretion system (T3SS) is an essential virulence determinant for Vibrio alginolyticus. In this study, we highlighted the significance of T3SS effector protein VopS in the V. alginolyticus infection. The vopS gene, which can promote the virulence of V. alginolyticus to Epinephelus coioides, is required for extracellular protease secretion. Also, it was demonstrated that VopS was involved not only in V. alginolyticus-mediated apoptosis but also in ferroptosis. Collectively, we identified that the VopS effector is a metabolic disruptor, promoting host cell ferroptosis. Vibrio alginolyticus is a Gram-negative pathogen of both marine animals and humans, resulting in significant losses for the aquaculture industry. Emerging evidence indicates that V. alginolyticus manipulates cell death for its pathogenicity, but the underlying molecular mechanisms remain unclear. Here, a gene designated vopS in V. alginolyticus HY9901 was identified, which was predicted to encode the T3SS effector protein. To determine whether VopS contributes to the pathogenesis of V. alginolyticus, the ΔvopS mutant strain was constructed and phenotypically characterized. The deletion of VopS not only reduced the ability to secrete extracellular proteases and virulence but also affected the expression of the T3SS genes. Furthermore, VopS was cytotoxic and induced apoptosis, as confirmed by elevated LDH and the activation of caspase-3. Metabolomic analysis revealed considerable metabolomic disruptions upon V. alginolyticus infection. The VopS effector induced host cell ferroptosis by promoting the synthesis of adrenic acid, depleting cellular glutathione, and subsequently increasing the accumulation of ferrous (Fe2+). Taken together, our findings provide that the VopS effector is an essential virulence factor of V. alginolyticus, which can lead to ferroptosis. [ABSTRACT FROM AUTHOR]

Understanding the foraging behavior of marine animals in Antarctica is crucial for assessing their ecological significance and responses to environmental changes, such as seasonal changes in seawater or light hours. However, studying their responses to these seasonal changes remains challenging due to the difficult logistics of conducting observations, particularly during the harsh austral winter months. In this study, we investigated the influence of changes in seawater properties and light conditions on the seasonal foraging behavior of Weddell seals (Leptonychotes weddellii) in the Ross Sea, Antarctica. We affixed 64 Weddell seals with conductivity–temperature–depth tags for 3 consecutive years from 2021 to 2023 to record their locations and dive profiles, including depth, head acceleration, temperature, and salinity. We found that seals foraged more frequently in Modified Shelf Water and Ice Shelf Water than in Antarctic Surface Water. This preference could be connected to greater food availability. Seals also dove to greater depths and displayed increased activity in capturing prey during daylight hours. This behavior may correspond to the diel vertical migration of pelagic prey in response to varying light conditions. Consequently, marine fauna were confronted with distinct seasonal changes in the Antarctic environment and adjusted their foraging behaviors to respond to them. This highlights the importance of extrinsic factors in estimating their seasonal foraging behavior. [ABSTRACT FROM AUTHOR]

Some marine animals form long‐lived luminescence for predation, communication, camouflage, and anti‐predation. These marine animals demonstrate soft nature, sustainable glowing, and underwater emission, which are difficult to achieve in synthetic room temperature phosphorescence (RTP) materials. Inspired by these marine animals, here the study reports RTP hydrogels that show long‐lived phosphorescence (lifetime >500 ms and afterglow >10 s) in water. Exceptional underwater mechanical properties are simultaneously achieved, including tensile strength of 5.1 MPa, tensile strain of 452%, and toughness of 19.3 MJ m−3. The key to this achievement lies in the in situ phase separation microarchitecture formed between polyacrylamide (PAM) and its partial hydrolysates, which confines the motions of polymer chains and protects vulnerable triplet excitons from quenching of water. Such a strategy shows the merits of facile fabrication without laborious synthesis. In addition, these RTP hydrogels offer repeatable photoprinting and highly stability in water, providing a versatile platform for underwater applications of RTP materials, including information encryption and camouflage of marine animals. [ABSTRACT FROM AUTHOR]

The Mississippian was an epoch of strong earth system changes, both tectonic and climatic. During the Mississippian, the marine faunas experienced a recovery after the late Devonian mass extinctions, and the rugose corals are a conspicuous example. This study tries to give a general view of the utility of rugose coral to reconstruct the palaeogeography in the Western Palaeotethys during the Mississippian. The methodology includes a database with the genera and species recorded in that area and time period, compiled using more than 700 articles and revisions of several collections in Europe. We worked with the six sub-provinces defined in previous studies for the Western Palaeotethys. A generic-level analysis was performed using paired group hierarchical clustering, building clusters for the Tournaisian, early Visean, late Visean and Serpukhovian. With that information, palaeomaps for those intervals have been illustrated and discussed. The rugose corals have some deficits for the reconstruction of the biogeography because of their strong palaeoecologic control and their insufficient and unequal record, but they provide important information that improves the knowledge on the palaeogeography of the studied region. [ABSTRACT FROM AUTHOR]

During scientific technical dives in a marine animal forest (MAF) environment, the nudibranch Dondice trainitoi Furfaro & Mariottini 2020 was recorded on a rocky bottom at 50 m depth in the Salento Peninsula, Southern Italy, Eastern Mediterranean Sea. Further in situ explorations and broad bibliographic research within both the scientific and grey literature revealed that D. trainitoi is widely distributed across the Mediterranean Sea, despite what was previously known. Herein are the first records for the Adriatic Sea and the Apulia region of Italy, together with the deepest record of this species. An analysis of collected samples and both in situ and laboratory photographs of the hydrozoan colonies associated with D. trainitoi revealed its ecology and trophic behaviour; we conclude that the hydrozoan Obelia bidentata Clark, 1875 is its preferred prey, but that it also feeds on the athecate hydroid Eudendrium glomeratum Picard, 1952. These findings shed some light on the little-known ecology and distribution, on both a geographical and a bathymetric scale, of this species, which are fundamental to increasing knowledge on Mediterranean biodiversity and its ecosystem functions. [ABSTRACT FROM AUTHOR]

Allorecognition—the ability of an organism to discriminate between self and nonself—is crucial to colonial marine animals to avoid invasion by other individuals in the same habitat. The cnidarian hydroid Hydractinia has long been a major research model in studying invertebrate allorecognition, establishing a rich knowledge foundation. In this study, we introduce a new cnidarian model Cladonema radiatum (C. radiatum). C. radiatum is a hydroid jellyfish which also forms polyp colonies interconnected with stolons. Allorecognition responses—fusion or regression of stolons—are observed when stolons encounter each other. By transmission electron microscopy, we observe rapid tissue remodeling contributing to gastrovascular system connection in fusion. Meanwhile, rejection responses are regulated by reconstruction of the chitinous exoskeleton perisarc, and induction of necrotic and autophagic cellular responses at cells in contact with the opponent. Genetic analysis identifies allorecognition genes: six Alr genes located on the putative allorecognition complex and four immunoglobulin superfamily genes on a separate genome region. C. radiatum allorecognition genes show notable conservation with the Hydractinia Alr family. Remarkedly, stolon encounter assays of inbred lines reveal that genotypes of Alr1 solely determine allorecognition outcomes in C. radiatum. RESEARCH HIGHLIGHTS: Introduction of the hydrozoan jellyfish Cladonema radiatum as a new cnidarian animal model, for studying invertebrate allorecognitionC. radiatum possesses effective allorecognition mechanisms mediated by a single gene Alr1. [ABSTRACT FROM AUTHOR]

In order to address a biological explanation for the different regenerative abilities present among animals, a new evolutionary speculation is presented. It is hypothesized that epigenetic mechanisms have lowered or erased regeneration during the evolution of terrestrial invertebrates and vertebrates. The hypothesis indicates that a broad regeneration can only occur in marine or freshwater conditions, and that life on land does not allow for high regeneration. This is due to the physical, chemical and microbial conditions present in the terrestrial environment with respect to those of the aquatic environment. The present speculation provides examples of hypothetic evolutionary animal lineages that colonized the land, such as parasitic annelids, terrestrial mollusks, arthropods and amniotes. These are the animals where regeneration is limited or absent and their injuries are only repaired through limited healing or scarring. It is submitted that this loss derived from changes in the developmental gene pathways sustaining regeneration in the aquatic environment but that cannot be expressed on land. Once regeneration was erased in terrestrial species, re-adaptation to freshwater niches could not reactivate the previously altered gene pathways that determined regeneration. Therefore a broad regeneration was no longer possible or became limited and heteromorphic in the derived, extant animals. Only in few cases extensive healing abilities or regengrow , a healing process where regeneration overlaps with somatic growth, have evolved among arthropods and amniotes. The present paper is an extension of previous speculations trying to explain in biological terms the different regenerative abilities present among metazoans. • The present opinion MS introduces epigenetics effects on animal regeneration • It is indicated that epigenetics changes occurred during animal evolution • These changes in the gene networks of marine animals erased high regeneration • It is indicated that they mainly affected animals adapting to the land • The terrestrial environment poses several restrictions to high regeneration [ABSTRACT FROM AUTHOR]

ABSTRACT The continuous requirement to substitute safe and affordable alternatives for helminth medications, as well as address the resistance of some used drug classes, introduced bioactive products derived from marine animals into the field of competition; however, almost all the previous research only focused on their impact on bacterial and protozoal infection. In the present work, we investigated the potential in vitro nematocidal effect of the aqueous extract of defense secretions for four species of marine mollusks: two cephalopods, namely the cuttlefish Sepia pharaonis and the common Octopus Octopus vulagris and two gastropods, the sea hare Aplysia argus and the sea slug Berthillina citrina, against the adult murine pinworm Syphacia obvelata. Data showed dose and time efficacy in all examined extracts. The sea slug's skin acid secretion has the highest impact, causing death in the cultivated worms, followed by the ink of the sea hare, the common octopus and the cuttlefish, where LC90 after 10 h of exposure were 250, 290, 316, and 391 µg/mL, respectively. Comparatively with the control and albendazole‐treated groups, the skin acid secretion of the sea slug caused the highest levels of the antioxidant enzymes SOD, Cat and GSH‐PX; however, albendazole prompted the highest level of GSH‐PX enzyme in all experimental groups. [ABSTRACT FROM AUTHOR]

With the continual increase in global cheese consumption, rennet, the traditional milk coagulant, is unable to meet the growing demand in cheese production. Although several proteases from other sources have been used for cheese-making, they suffer various shortcomings. The ocean is home to a huge and diverse range of life forms, which represent a vast potential source of proteases. Marine proteases have been isolated from a number of marine species, including sponge, jellyfish, seaweed and marine animals, and some have been shown to be suitable as milk-clotting enzymes for cheese making. This review summarizes the latest studies on rennet substitutes from marine resources and their role in cheese-making. The emphasis of the review is on the isolation and purification of the marine proteases, the biochemical characteristics of these enzymes, especially their caseinolytic and milk-clotting properties, as well as their cleavage sites on casein. Some of the marine proteases have been applied as milk-clotting agent in cheese-making, with the resultant production of cheese with comparable characteristics, including sensory characteristics, to calf rennet cheese. The review concludes by highlighting the challenges and opportunities for future research in the field. [ABSTRACT FROM AUTHOR]

From the first animals crawling on the sea floor to pterosaurs rising to the sky with wingspans up to ten metres across, understanding animal moves of the deep evolutionary past remains a challenge. In addition to exceptional fossils, advanced computer modelling methods and soft robotics are now helping to elucidate how bygone species were able to walk, swim and fly. Michael Gross reports. From the first animals crawling on the sea floor to pterosaurs rising to the sky, understanding animal moves of the deep evolutionary past remains a challenge. In addition to exceptional fossils, advanced computer modelling methods and soft robotics are now helping to elucidate how bygone species were able to walk, swim and fly. [ABSTRACT FROM AUTHOR]

Marine and ocean pollution is one of the most serious environmental problems in the world. Marine plastics pose a significant threat to the marine ecosystem due to their negative effects. After passing through various processes, plastic waste accumulates on the seafloor and fragments into very small pieces known as microplastics. These microplastics are to blame for the extinction and death of aquatic life. This study obtained a hybrid underwater dataset containing 13,089 images, sized 300 × 300, including garbage and sea animals. In the proposed method, this dataset is used to develop our example projector deep feature generator. In this study, using the Resnet101 network in a sample projector build, the feature generator creates 6,000 features. Using NCA (Neighborhood Component Analysis), the best 1000 features from a pool of 6,000 are selected. The kNN (k-nearest neighbor) algorithm is then used to classify the resulting feature vectors. As validation techniques, both tenfold cross-validations were used. The hybrid dataset's best accuracy was calculated to be 99.35%. Our recommendation is successful based on the comparisons and calculated performance measures. [ABSTRACT FROM AUTHOR]

Background Plitidepsin has shown potent preclinical activity against severe acute respiratory syndrome coronavirus 2 and was generally well tolerated in a phase I trial of hospitalized patients with coronavirus disease 2019 (COVID-19). NEPTUNO, a phase III, multicenter, randomized, controlled trial, was designed to evaluate the efficacy and safety of plitidepsin in the management of moderate COVID-19 in hospitalized adult patients. Methods Included patients had documented severe acute respiratory syndrome coronavirus 2 infection, required oxygen therapy, and had adequate organ function. The planned sample size was 609 patients. Patients were randomized 1:1:1 to at least 3 days of dexamethasone plus either plitidepsin (1.5 mg/day or 2.5 mg/day, for 3 days) or standard of care (control). The primary endpoint was the time to sustained withdrawal of supplemental oxygen. Secondary endpoints included time to sustained hospital discharge, clinical status, duration of oxygen support, percentage of patients requiring admission to the intensive care unit, and safety. Results After randomizing 205 patients, NEPTUNO was discontinued due to a notable drop in COVID-19–related hospitalizations. Available data suggest a 2-day improvement in the median time to sustained oxygen therapy discontinuation (5 vs 7 days) favoring both plitidepsin arms (hazard ratio, 1.37; 95% confidence interval,.96–1.96; P =.08 for plitidepsin 1.5 mg vs control; hazard ratio, 1.06; 95% confidence interval,.73–1.53; P =.78 for plitidepsin 2.5 mg vs control). Plitidepsin was generally well tolerated. Conclusions Despite the trial limitations, these results suggest that plitidepsin may have a positive benefit-risk ratio in the management of patients requiring oxygen therapy. Further studies with plitidepsin, including those in immunosuppressed patients, are warranted. Results from this phase III trial suggest that plitidepsin, a first-in-class antiviral, may have a positive benefit-risk ratio in the management of hospitalized patients requiring oxygen therapy for moderate COVID-19. [ABSTRACT FROM AUTHOR]

Marine animals orchestrate the swimming process through the coordinated interplay of body musculature, the caudal peduncle, and the caudal fin. However, understanding the coordinated action of these components to achieve high propulsive performance remains a significant challenge. The study proposes a self-propulsive physical model with two-degree-of-freedom (DoF) elastic coupling inspired by the caudal peduncle, where the caudal peduncle exhibits spring-like behaviors influencing the tail's motion along heave/pitch directions. The complex nonlinear fluid–structure interaction issues are addressed via the nonlinear vortex sheet method. The study primarily compares the propulsive performance of the two-DoF elastic coupling caudal fin model with the pitch caudal fin model. Numerical results show that the peak efficiency of the proposed model is nearly eight times that of the pitch caudal fin model. Additionally, the study reveals that the high-propulsive mechanism lies in generating the figure of a butterfly phase diagram for the hydrodynamic forces and exploiting vortices to decrease energy consumption. These findings offer novel perspectives for the future design of high-efficiency underwater robots. [ABSTRACT FROM AUTHOR]

This paper presents a machine learning-based airfoil shape optimization framework designed to increase flutter resistance and reduce drag. Using the National Advisory Committee for Aeronautics airfoil as the base design and a Hicks–Henne bump function, we employ multi-objective Bayesian optimization and harmonic balance-based flutter prediction. The optimization process yields a Pareto front revealing trade-off relationships between the flutter speed index and drag coefficient. The optimized airfoils, resembling those of evolved marine animals, outperform the base design in terms of flutter resistance and drag. These results demonstrate the framework's potential to enhance aircraft performance and safety by addressing aeroelastic factors. [ABSTRACT FROM AUTHOR]

Small vessels (<10 m) radiate underwater noise in sensitive coastal environments, but there is insufficient knowledge of their noise radiation. Through detailed measurements of seven small boats and a jet ski in a shallow water environment on the Swedish west coast, this study presents results on the speed dependence of small vessel underwater noise, its sources, and its directivity. For vessels with planing hulls, broadband source levels increase with speed until planing is attained. When planing, source level dependence on speed is weak. A detailed noise source analysis of one vessel showed that at low speed, tonals from the engine dominate the noise radiation, whereas at higher speeds, propeller tonals and broadband noise dominate. Noise radiation into different horizontal angles shows little angle dependence, and noise levels relative to the closest point of approach show a similar pattern across all investigated vessels. Received noise levels at approximately 100 m range are not high enough to cause hearing impairment in marine animals, but fast-moving small vessels may cause behavioural reactions or stress responses across several marine animal groups. [ABSTRACT FROM AUTHOR]

Marine animals often harbour complex microbial communities that influence their physiology. However, strong evidence for resident microbiomes in marine bivalves is lacking, despite their contribution to estuarine habitats and coastal economies. We investigated whether marine bivalves harbour stable, resident microorganisms in specific tissues or if their microbiomes primarily consist of transient members reflecting the environmental microbial pool. Conducting a latitudinal study of wild eastern oysters (Crassostrea virginica) along the East Coast of the United States, we aimed to identify resident microorganisms that persist across a wide geographical range. Our results revealed that microbial communities in seawater and sediment samples followed latitudinal diversity patterns driven by geographic location. In contrast, oyster‐associated microbiomes were distinct from their surrounding environments and exhibited tissue‐specific compositions. Notably, oyster microbiomes showed greater similarity within the same tissue type across different geographic locations than among different tissue types within the same location. This indicates the presence of tissue‐specific resident microbes that persist across large geographical ranges. We identified a persistent set of resident microbiome members for each tissue type, with key microbial members consistent across all locations. These findings underscore the oyster host's role in selecting its microbiome and highlight the importance of tissue‐specific microbial communities in understanding bivalve‐associated microbiomes. [ABSTRACT FROM AUTHOR]

Simple Summary: Photobacterium damselae subsp. damselae (Pdd) is a marine bacterium that can infect a variety of marine animals and humans. Although this bacterium has been isolated from several stranded dolphins and whales, its pathogenic role in cetaceans is still unclear and very limited information exists on its occurrence in these animals. In this study, we report data relating to the presence of Pdd in marine mammals stranded within the Liguria Pelagos Sanctuary from 2017 to 2022. Our findings show a 41.5% (22/53) Pdd prevalence in stranded cetaceans, where 22.7% (5/22) of these were positive in at least one of the Pdd virulence factors which, in previous studies, have been related to Pdd pathogenicity. Our results also revealed that in all cases where cetaceans tested positive for Pdd, other well-known pathogens for these species were also present. This finding supports the hypothesis that Pdd is an opportunistic agent that might contribute to the worsening of health conditions in subjects already compromised by other pathogens, contributing to their death. However, further studies are necessary to investigate and deepen this hypothesis. Photobacterium damselae subsp. damselae (Pdd) is an increasingly common bacterium in post-mortem diagnostics of beached marine mammals, but little is known about its precise etiological responsibility. To estimate the prevalence of Pdd in stranded cetaceans from 2017 to 2022 on the Ligurian coast (Pelagos Sanctuary), we tested tissues from 53 stranded individuals belonging to four cetacean species. DNA extracts from cetacean tissue were screened using a polymerase chain reaction (PCR) assay targeting the Pdd ureC gene. Positive samples were screened by PCR for dly, hlyApl and hlyAch hemolysin genes, which were confirmed by sequencing. Twenty-two out of 53 (41.5%) cetaceans analyzed by PCR were confirmed for Pdd DNA in at least one tissue among those analyzed. Five of these cetaceans were positive for at least one of the hemolysin genes tested. In all Pdd-positive cetaceans, other pathogens that were considered responsible for the causa mortis of the animals were also found. The results provide new information on the spread of Pdd in cetaceans and support the thesis that Pdd might be an opportunistic agent that could contribute to worsening health conditions in subjects already compromised by other pathogens. However, further studies are needed to investigate and deepen this hypothesis. [ABSTRACT FROM AUTHOR]

A new steroid, 2a-oxa-2-oxo-5β-hydroxy-3,4-dinor-24-methylcholesta-22E-ene (1), together with 10 known ones (2–11), was isolated from the marine sponge Cliona sp. The structures of these compounds were determined by the spectroscopic methods (UV, IR, MS, and NMR) and X-ray diffraction analysis. Compound 1 was the third example of 3,4-dinorsteroid with a hemiketal at C-5 that was isolated from the natural source. In addition, the antibacterial activities of these compounds were also evaluated. However, none of them exhibited significant inhibition effects. [ABSTRACT FROM AUTHOR]

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Social developments are bringing about changes in how we communicate and represent ideas. With the tendency of globalisation, marine ecosystems are facing threats such as overfishing, pollution, and climate change, and marine ecological protection has become a focus of attention for all countries. This paper adopts Kress and van Leeuwen's framework of visual grammar analysis to compare and analyse the use of symbols in Chinese and Western marine ecological protection posters from the perspectives of representational meaning, interactive meaning, and compositional meaning. Qualitative and quantitative analyses of 100 Chinese posters and 100 Western posters reveal similarities and differences in symbol selection, cultural context, and compositional approach. Results show that Chinese posters tend to integrate traditional cultural elements and natural symbols to convey the concept of environmental protection in a harmonious and warm way, such as the use of ink painting style and paper-cutting art to represent marine organisms, while Western posters focus on directly displaying the hazards of marine pollution by means of strong visual contrasts and modern design elements to stimulate the audience's sense of urgency and responsibility, such as the display of marine animals trapped by plastic rubbish. This research not only deepens the understanding of the theory of visual grammar but also provides valuable references for the design of future environmental posters, emphasising the importance of using visual symbols and communication strategies in different cultural contexts in order to convey environmental messages more effectively and to promote the development of global marine conservation. [ABSTRACT FROM AUTHOR]

Marine creatures have an abundance of polysaccharides, active proteins, active peptides, and amino acids. With advancements in separation extraction and structure-activity relationship analysis technology, marine animal polysaccharides, as important components of marine animal active ingredients, are shown to exhibit a variety of biological activities such as immune regulation, hypoglycemic activities, antioxidant effects, lipid-lowering processes, and anticancer properties. This article examines the different types, biological activities, and applications of polysaccharides in biomedicine, aquaculture, food, cosmetics, and proposes potential research directions for pursuit by providing theoretical reference to promote the high-value and ecological development and utilization of marine animals.

Hitherto unreported whale fall fauna has been found from the Lower Miocene of Khari Nadi Formation of Kutch, India.This vertebrate-invertebrate assemblage comprises jumbled up bone fragments of different parts of the whale along with molluscs and echinoids. Some representatives in this assemblage are characteristic whale fall fauna and some are characteristic shallow marine fauna. The molluscs belong to the families Buccinidae, Provannidae, Naticidae, Turritellidae, Borsoniidae, Volutidae, Haminoeidae, Cypraeidae, Strombidae, Rostelleriidae, Cassidae, Osteridae, Veneridae, Astartidae and the echinoids to family Spatangidae and Schizasteridae. The present study reveals that the deposition of this entire assemblage was in a shallow marine environment and also sheds some light on the molluscan association related to a whale fall from the western Indian sea waters in the Lower Miocene. [ABSTRACT FROM AUTHOR]

The focus of the present study was on arcturid isopods occurring in the subarctic region around Iceland. Data from two decades of sampling with an epibenthic sledge (EBS) during numerous expeditions of the BIOICE (Benthic Invertebrates of Icelandic Waters; 1992–2004) and IceAGE (Icelandic marine Animals: Genetics and Ecology; 2011—ongoing) projects were incorporated into an integrative taxonomy approach. This approach linked distribution records, morphological and molecular examinations, with video and image data observed during recent expeditions in 2018 (MSM75) and 2020 (SO276) using the Remotely Operated Vehicles (ROVs) PHOCA and Kiel 6000 from GEOMAR. The resulting dataset from 120 sampling locations included 6852 specimens, a large percentage of which were fixed in formalin during BIOICE. Ethanol‐fixed specimens collected during IceAGE were used to link morphotypes with haplotypes and occurrence locations, focusing on the coral association of the genus Astacilla Cordiner, 1793. The IceAGE sampling was complemented by ROV image and video data and noninvasive sampling, making it possible to obtain pictures of living specimens of A. longicornis. The species A. longicornis Sowerby, 1806 showed a distribution linked to cold‐water occurrence and was sampled from Paramuricea placomus. Astacilla boreaphilis Stranky & Svavarsson, 2006, occurring only south of Iceland, showed high morphological variation in the spine pattern of adult females, while the molecular results indicated no clear pattern of potentially ongoing species radiation or cryptic species. Astacilla granulata was exclusively found north of Iceland. Thus, the species' distribution is potentially influenced by the Greenland‐Faroe Ridge, which separates the North Atlantic from the Arctic Ocean. [ABSTRACT FROM AUTHOR]

The Magnisi peninsula is a small portion of land located near the largest Italian petrol-chemical pole of Augusta–Priolo–Melilli (40 km2), which, since the 1950s, devastated the local environment and landscape and unloaded directly into the sea an impressive quantity of pollutants. Unlike the terrestrial part of the area, where a Natural Oriented Reserve (NOR) called "Saline di Priolo" was established in the 2000s, no concrete legislative action has been implemented or proposed for the marine environment. At the same time, the fauna of the marine environment has not been studied in the same way as that of the terrestrial environment. As concerns the molluscan fauna, most of the information dates back to the 1800s. These studies were exclusively focused on the shells of some mollusks in the area. Instead, no study related to this area has ever been carried out on the group of sea slugs. This study conducted between 2022 and 2023, through snorkeling activities, allowed to provide the first faunistic list of the sea slugs of this area, together with information on the biology and ecology of these gastropods, highlighting the potential biodiversity present in this small stretch of coastline affected by high industrial pollution. [ABSTRACT FROM AUTHOR]

For decades, many marine animals have been considered to exhibit cosmopolitan or transoceanic distribution. This situation is prevalent in Asia, where many species were collected and named by American or European experts in the 1700s to early 1900s. Using the windowpane oysters Placuna—a small genus of bivalves with five recognized species—we show that careful analysis is required to reassess the validity of these species. Currently, only two species of Placuna (P. placenta and P. ephippium) widely reported in the Indo‐Pacific region have been recorded from Chinese coastal waters. Here, we described two new species of Placuna from China. Placuna vitream sp. nov. can be distinguished from P. placenta by its larger ridge angle. Phylogenetic analysis using five gene fragments fully supported that P. vitream sp. nov. is a sister to the specimen from Singapore identified as P. placenta and more distant from other Placuna species with available molecular data. Besides, based on subfossil shells, we describe Placuna aestuaria sp. nov. that differs from its congeneric species by its broad hinge, medium ridge angle, and nearly straight ridges. Finally, we suggest a combination of hinge structure and ridge angle that can be used for identifying Placuna species and preparing a key to this genus. Our findings of two new species expand the diversity of Placuna and prompt reassessment of the many presumably widely distributed marine species in Asia. [ABSTRACT FROM AUTHOR]

Coralligenous, a typical Mediterranean mesophotic habitat, is a highly diverse assemblage, severely threatened by several stressors, including fishing litter. To characterise the coralligenous of the upper mesophotic of the Portofino Promontory (Ligurian Sea, Italy), video transects at 35 and 50 m depth were performed at four sites. Benthic assemblages and lost fishing gears were recorded, and the two depths compared. A higher coverage of taxa with complex 3D structures was found at 50 m, mainly due to the gorgonian Paramuricea clavata. However, the overall low density of this species (0.4–6.6 colonies/m2), together with the impact caused by 120 fishing lines found along the transects, highlights the need for tailored conservation measures. With climate change moving further down the water column and fishing impacts being a major cause of degradation, the design of marine protected areas needs to be extended to include mesophotic depths, contributing to the 30 × 30 targets agreed upon at the COP15. [ABSTRACT FROM AUTHOR]

The field of bioinspired underwater robots aims to replicate the capabilities of marine animals in artificial systems. Stingrays have emerged as highly promising species to be mimicked because of their flat body morphology and size. Furthermore, they are considered high-performance species due to their maneuverability, propulsion mode, and sliding efficiency. Designing and developing mechanisms to imitate their pectoral fins is a challenge for underwater robotic researchers mainly because the locomotion characteristics depend on the coordinated movement of the fins. In the state of the art, several mechanisms were proposed with 2 active rotation degrees of freedom (DoFs) to replicate fin movement. In this paper, we propose adding an additional active DoF in order to improve the realism in the robotic manta ray movement. Therefore, in this article, we present the mechanical design, modeling, and kinematics analysis of a 3-active-and-rotational-DoF pectoral fin inspired by the Mobula Alfredi or reef manta ray. Additionally, by using the kinematics model, we were able to simulate and compare the behaviour of both mechanisms, that is, those with 2 and 3 DoFs. Our simulation results reveal an improvement in the locomotion, and we hypothesized that with the third DoF, some specific missions, such as hovering or fast emergence to the surface, will have a better performance. [ABSTRACT FROM AUTHOR]

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Marine creatures have an abundance of polysaccharides, active proteins, active peptides, and amino acids. With advancements in separation extraction and structure-activity relationship analysis technology, marine animal polysaccharides, as important components of marine animal active ingredients, are shown to exhibit a variety of biological activities such as immune regulation, hypoglycemic activities, antioxidant effects, lipid-lowering processes, and anticancer properties. This article examines the different types, biological activities, and applications of polysaccharides in biomedicine, aquaculture, food, cosmetics, and proposes potential research directions for pursuit by providing theoretical reference to promote the high-value and ecological development and utilization of marine animals. [ABSTRACT FROM AUTHOR]

Although human‐made barriers to animal movement are ubiquitous across many types of ecosystems, the science behind these barriers and how to ameliorate their effects lags far behind in marine environments compared with terrestrial and freshwater realms. Using juvenile sawfish in an Australian nursery habitat as a model system, we aimed to assess the effects of a major anthropogenic development on the movement behavior of coastal species. We compared catch rates and movement behavior (via acoustic telemetry) of juvenile green sawfish (Pristis zijsron) before and after a major coastal structure was built in an important nursery habitat. Acoustic tracking and catch data showed that the development did not affect levels of sawfish recruitment in the nursery, but it did constrain movements of juveniles moving throughout the nursery, demonstrating the reluctance of shoreline‐associated species to travel around large or unfamiliar coastal structures. Given the current lack of information on human‐made movement barriers in the marine environment, these findings highlight the need for further research in this area, and we propose the development of and experimentation with marine animal crossings as an important area of emerging research. [ABSTRACT FROM AUTHOR]

Simple Summary: Our study provides the first record of Pacific sleeper sharks in 1629 m deep waters off the southeast coast of Hainan Island in the South China Sea. At a site, we placed a dead cow as bait and a metal-framed cage with cameras and observed eight individuals and their feeding activities by using ROV diving. The record indicates an expansion of the known distribution range of the Pacific sleeper sharks to the west of the northern South China Sea. Such a finding demonstrates that the habitat ranges of large animals are far wider in deep seas than we know from observations in the upper layer, and habitat expansion of some animal populations may have already taken place under intensive anthropogenic influences such as climate changes. We conducted an experiment of planting a dead cow and a metal-framed cage with cameras on the 1629 m deep sea floor off the southeast coast of Hainan Island in the northwestern South China Sea, using ROV diving and setting up a video camera on the cage to observe animals who came to eat the bait. The deep-sea cameras captured footage of eight Pacific sleeper sharks (Somniosus pacificus) swimming and feeding around the dead cow. To our knowledge, this is the first time the occurrence of such a shark species has been reported in the South China Sea. Eight individuals were differentiated based on the characteristic differences displayed in the images, with lengths of 1.9 to 5.1 m estimated. The video camera also recorded the predators' behavior of tearing at the dead cow on the seabed. It was discovered that Pacific sleeper sharks are not strictly solitary and exhibit queue-feeding behavior. This study is significant as it documents a record of a data-scarce shark species, for which little information is available in the literature. It also documents an expansion of the species' known habitat from the north Pacific Ocean into the South China Sea. Such sharks diving into the deep sea to predate on dead animals also suggests that occurrences of large chunks of dead organic bodies falling onto the deep sea might have been more frequent than we previously thought in the South China Sea. The findings have implications for understanding the geographic connectivity of large swimming animals between the South China Sea and the Pacific Ocean and provide scientific evidence for formulating conservation and management strategies for sharks and other large animals in the oceans. [ABSTRACT FROM AUTHOR]

Individual specialization may occur relative to diet, behaviour or spatial distribution, potentially leading to differential resource and space use within a population. While specializations have been documented across many animal populations, the underlaying causes of individual specialization (e.g. morphology, age or sex) are not always identified. Causes of specialization can be especially challenging to uncover for large, long-lived marine animals. We used a Bayesian multilevel, multinomial logistic regression model to study the relationships between grey whale, Eschrichtius robustus , use of foraging tactics and morphology (body length and condition), while accounting for habitat characteristics and individual variation in tactic use. The model was informed by a 7-year longitudinal data set of concurrent morphology and foraging behaviour collected using drones. We found evidence of an ontogenetic shift in the use of foraging tactics associated with body length (a proxy for age). Individual specialization in behaviour was also associated with water depth and habitat. After accounting for the effects of these covariates, there was some residual individual level variation in the use of different foraging tactics. Our findings demonstrate variation in resource and habitat use within a baleen whale population at the individual level relative to body length and habitat, suggesting that individual spatial distribution and access to prey may vary by age class. Our results can be applied to investigate whether juveniles and adults differ in their foraging success and resilience to stressors. • We used drones to measure behaviour and morphology of eastern grey whales. • Whale foraging behaviours were associated with morphology and habitat type. • Different foraging tactics were associated with different depths and habitat types. • Whales switched foraging tactics as they grew in length. • Morphology affected habitat and prey accessibility and consequently tactic use. [ABSTRACT FROM AUTHOR]

Fluorescence in marine animals has mainly been studied in Cnidaria but is found in many different phyla such as Annelida, Crustacea, Mollusca, and Chordata. While many fluorescent proteins and molecules have been identified, very little information is available about the biological functions of fluorescence. In this review, we focus on describing the occurrence of fluorescence in marine animals and the behavioural and physiological functions of fluorescent molecules based on experimental approaches. These biological functions of fluorescence range from prey and symbiont attraction, photoprotection, photoenhancement, stress mitigation, mimicry, and aposematism to inter‐ and intraspecific communication. We provide a comprehensive list of marine taxa that utilise fluorescence, including demonstrated effects on behavioural or physiological responses. We describe the numerous known functions of fluorescence in anthozoans and their underlying molecular mechanisms. We also highlight that other marine taxa should be studied regarding the functions of fluorescence. We suggest that an increase in research effort in this field could contribute to understanding the capacity of marine animals to respond to negative effects of climate change, such as rising sea temperatures and increasing intensities of solar irradiation. [ABSTRACT FROM AUTHOR]

The Amber Cow is a legendary creature with special characteristics, whose story has a wide reflection in Persian poetry and prose texts, so that we can recover a sign of it from the oldest sources available to this day. Of course, despite the age of this legend and the frequent references to it in various texts and also the wrong understanding of quiddity of this creature, it is surprising that no befitting research has been done about this creature. With the aim of investigating the origin, age and various narratives of its story, as well as determining the characteristics of this legendary creature based on various sources and documents, this research has dealt with how the story of this cow is reflected. The authors have collected the materials related to the subject by examining various sources, including the books of strange creatures and narrative, mythology, legends, history, and texts. They have been categorized and analyzed by descriptive-analytical method using library study and note taking. Among the findings of this research is the presentation of the historical process of the story and its related changes in the texts of different periods, as well as determining the identity of this cow and distinguishing it from similar animals and real sea cows [ABSTRACT FROM AUTHOR]

While marine animal behavior is often studied in constrained lab setups, a more reliable exploration should be done in their natural environment and without human interference. This task becomes excessively more challenging when quantitative data are needed in large and unconstrained aquatic environments. Toward that end, researchers widely use acoustic positioning telemetry to remotely track their subjects, though this often requires an extensive network of receivers placed in the environment ahead of time. This study proposes a new tracking method that continuously tracks and reports the trajectory of a target in unconstrained marine environments using a single‐moving acoustic receiver. Instead of deploying an extensive array of static receivers, we use a single receiver mounted on an autonomous surface vehicle to obtain highly accurate results with much cheaper and simpler means. The receiver position and earlier target location estimations are used to calculate an optimal trajectory for the receiver, which in turn provides subsequent readings and target localizations based on a new variant of the Time Difference of Arrival approach. We demonstrate the performance of the proposed methods using both simulations and field experiments. [ABSTRACT FROM AUTHOR]

In this work, the concentrations of hazardous elements (As, Cd and Pb) in the edible portion of the Perna perna mussel from Southeast Brazil were analyzed to understand the effects of the COVID-19 pandemic on the coastal environment and to evaluate the quality of this fishery resource. Decreases in anthropogenic chemical outputs to the environment were expected to occur during the COVID-19 pandemic, with decreases in element concentrations in mussels. The ranges of median concentrations (µg g−1 dw) in the pre- and pandemic periods were 5.4–16.1 and 2.2–10.6 for As; 0.2–0.6 and 0.1–0.5 for Cd; and 1.2–3.2 and 0.7–1.8 for Pb, respectively. Temporal variations (prepandemic x pandemic) were more significant than spatial variations (five sampling sites). The relationships between the concentrations of hazardous elements and isotopic ratios (δ15N and δ13C) suggested that food sources were more diverse across the sampling sites during the pandemic period, when individuals exhibited less efficient trophic transfer. The concentrations of Cd and Pb were below the tolerable maximum limit, whereas for As, they were above the limit; however, these concentrations are not a risk to human health, as most As was present in the least toxic organic form. The intake estimates were below the tolerable intake limits, and only Pb concentrations are at risk of causing concern if the intake of mussels increases. This is the first study in Brazil that presents a spatial–temporal comparison of hazardous elements in marine fauna considering COVID-19 as a temporal landmark. The results are of interest for both public health and environmental health management in a post-COVID-19 scenario. [ABSTRACT FROM AUTHOR]

Scientists, hunters and business entrepreneurs in the Carolinas all had mutual interests in giant manta rays (Mobula birostris) during the early decades of the 1900s. Eastern-seaboard coastal communities called them devil fish, because of the horn-shaped fins on their head. Although the Ocean Leather Company in Morehead City primarily processed shark-skin leather, it also experimented with the skins of rays and other sea animals for the manufacture of a great variety of consumer products. Articles were written for scientific journals and ray specimens were contributed to national institutions like the American Museum of Natural History. Local fishermen, along with celebrities like the US president, Teddy Roosevelt, harpooned devil fish in Cape Lookout while marvelling at their grace and strength, breaching up to six feet above the water's surface. Beaufort planter William Elliott presented many accounts of this fantastic sea creature, with vivid stories of enslaved African harpooners jumping off boats onto the backs of giant manta rays. This research combines historical accounts and images, newspaper advertisements and talks at local explorer clubs to illustrate case studies of the community's obsession with collecting, cooking, hunting and conquering rays as an important component of maritime leisure and environmental history. It concludes by addressing international examples of subsistence, recreational and industrial fishing, and its impacts on manta rays. [ABSTRACT FROM AUTHOR]

This study presents a hybrid method, namely the marine predator algorithm (MPA) and Aquila optimizer (AO). The proposed algorithm is named MAO. AO duplicated the existence of the Aquila bird in nature while hunting for prey while MPA was inspired by predators in marine animal life. Although AO is widely accepted, it has several disadvantages. This causes various weaknesses such as a weak exploitation phase and slow growth of the convergence curve. Thus, certain exploitation and exploration in conventional AO can be studied to achieve the best balance. The MPA demonstrates the capacity to deliver optimal design and statistically efficient outcomes. The proposed method used AO as the main algorithm. To measure the performance of the proposed method, this study depicted a comparison using the AO, MPA, and whale optimization algorithm (WOA) methods. This paper was evaluated the performance of MAO on twenty-one CEC2017 benchmark functions test and droop control performance on direct current (DC) microgrid. From the simulation, MAO shows superior convergence ability. The proposed method and its application to droop control was successfully implemented and implied a promising performance. [ABSTRACT FROM AUTHOR]

Global climate‐driven ocean warming has decreased dissolved oxygen (DO) levels (ocean deoxygenation) leading to expansions of hypoxic zones, which will affect the movements, behaviour, physiology and distributions of marine animals. However, the precise responses of animals to low DO remains poorly understood because movements and activity levels are seldom recorded alongside instantaneous DO in situ.We describe a new animal‐attached (dissolved oxygen measuring, DOME) archival tag with an optical oxygen sensor for recording DO, in addition to sensors for temperature and depth, a triaxial accelerometer for fine‐scale movements and activity, and a GPS for tag recovery. All sensors were integrated on a single electronic board.Calibration tests demonstrated small mean difference between DOME tag and factory‐calibrated DO sensors (mean relative error of 5%). No temporal drift occurred over a test period three times longer than the maximum deployment time. Deployments on four blue sharks (Prionace glauca) in the central North Atlantic Ocean showed regular vertical oscillations from the surface to a maximum of 404 m. Profiles from diving sharks recorded DO concentrations ranging from 217 to 272 μmol L−1, temperatures between 13°C and 23°C, and identified an oxygen maximum at ~45 m depth, all of which were consistent with ship‐based measurements. Interestingly, the percentage of time sharks spent burst swimming was greater in the top 85 m compared to deeper depths, potentially because of higher prey availability in the surface layer.The DOME tag described blue shark fine‐scale movements and activity levels in relation to accurately measured in situ DO and temperature, with the potential to offer new insights of animal performance in low oxygen environments. Development of a tag with physico‐chemical and movement sensors on a single electronic board is a first step towards satellite relay of these data over broader spatiotemporal scales (months over thousands of kilometres) to determine direct and indirect responses of marine animals to heatwave and deoxygenation events. [ABSTRACT FROM AUTHOR]

The ability to identify individual animals can provide valuable insights into the behaviour, life history, survivorship, and demographics of wild populations. Photo-identification (photo-ID) uses unique natural markings to identify individuals and can be effective for scalable and non-invasive research on marine fauna. The successful application of photo-ID requires that chosen distinguishing markings are unique to individuals and persist over time. In this study, we validate the use of dorsal spot patterns for identifying individual blue-spotted ribbontail rays (Taeniura lymma) in conjunction with traditional tagging methods. Spot patterns were unique among T. lymma with 90.3% of individuals correctly identified using I3S photo-matching software from images taken up to 496 days apart. In comparison, traditional physical tagging methods showed a tag loss rate of 27% and a maximum tag retention period of only 356 days. Our findings demonstrate the effectiveness of photo-ID as a tool to monitor populations and better understand the ecology of the blue-spotted ribbontail ray without the need for physical tagging. The validation of photo-ID for this widespread species is important as it enables behavioural and demographic changes to be easily tracked in relation to coastal threats such as human development and habitat degradation. [ABSTRACT FROM AUTHOR]