The capture of a rare, critically endangered adult angular rough shark, Oxynotus centrina (Linnaeus, 1758), with abnormal coloration is reported in this paper. The shark exhibited a partial reduction in pigmentation, resulting in an overall pale appearance with white-greyish patches. Since the retinal pigmentation appeared normal, the shark was considered leucistic. This represents the first documented case of leucism in this species and the first colour disorder reported in the family Oxynotidae Gill, 1912. Despite the atypical appearance, the physical health of the shark seemed unaffected, supporting the notion that pigment disorders in deep-sea sharks do not inherently impair survival and growth. Full morphometric characteristics are presented and compared with those of a normal individual of the same sex caught in the same area, showing no differences.

The sharpnose sevengill shark (Heptranchias perlo) is a rare and poorly understood deep‐sea species, with only a few records in the Adriatic Sea over the last two centuries and a significant gap in sightings. Throughout 2023, three new records are documented in the southernmost Adriatic Sea, found at depths ranging from 391 to 452 m off Vlorë. This study marks the first comprehensive health examination of a deep‐sea shark, investigating potential trauma and injuries resulting from trawling. It encompasses pathological and histopathological examinations, supplemented by magnetic resonance imaging (MRI). The research highlights alarming post‐capture mortality rates in this data deficient species, discusses further conservation implications, and proposes protective measures for the species. Beyond addressing critical knowledge gaps, this study advocates for collaborative efforts with local fishermen to establish long‐term monitoring and obtain data on the frequency and abundance of elusive species.

This paper describes the first record of the critically endangered gravid female Spiny butterfly ray, Gymnura altavela (Linnaeus, 1758), in the northern Mediterranean and simultaneously the only record of the species in this century for the Adriatic Sea. The female (173 cm disc width and 43.25 kg total weight) was captured at approximately 200 m, off Vlorë in the southern Adriatic Sea off Albania on 12th of May 2022. Upon necropsy, seven near-term fetuses (mean 328 ± 6.47 mm disc width and mean 355 ± 20.06 g in total weight) were transported for further in-vitro incubation. These results represent the deepest capture for the species, as well as the largest litter size and largest size at birth in the Mediterranean Sea which indicates the need for further research.

This paper is describing a new finding of Carcharhinus plumbeus (Nardo, 1927) caught at the insular shelves off the Sazan Island at the depth of 120 m, which is the southernmost record for a sandbar shark in the Adriatic Sea. The individual had a partially healed umbilical scar and is considered as neonatal. Examined shark appeared in good body condition with showed no macroscopic signs of diseases or macroscopic parasites. Detailed morphometric measurements are compared with four neonate and juvenile specimens from the north and central Adriatic Sea and are provided in the paper. Despite it is not possible to establish a certain conclusion on whether our specimen was born in the studied area or elsewhere, presented finding provides the very first evidence that neonatal sandbar sharks can be found along the coast of Albania. Knowing the exact locations and movements of both neonates and juveniles is of high importance for the effective long-term in-situ conservation.

Abstract Historically, two angel shark species, common angel shark Squatina squatina and smoothback angel shark Squatina oculata, were common in the upper continental shelf of the eastern Adriatic Sea. Although both species are considered critically endangered in the Adriatic and the rest of the world, there are almost no data on the current status of populations, threat assessment and species-specific in-situ conservation. Common angel shark is still present in highly fragmented areas of the eastern Adriatic with extremely rare but consistent records, while smoothback angel shark is mostly considered regionally extinct in the Adriatic due to overfishing and overuse of non-selective fishing gear. There have been only 3 published records of common angel shark this century, the last two of which were reported by fishermen. This paper presents data on 34 new finds, including neonates, juveniles, subadults and adults recorded between January 2020 and August 2021 in the Zadar-Šibenik archipelago (central Adriatic) and one in Premantura (northern Adriatic). Two are original findings during the field expedition, 9 were reported directly by local fishermen, while 23 were reported through a detailed questionnaire. Additionally, plausible breeding and/or nursery grounds between Zadar and Šibenik are discussed with their importance for revitalization and long-term conservation in situ.

Though SARS-CoV-2 infections are yet to be completely characterised in a host-pathogen interaction context, some of the mechanisms governing the interaction between the novel betacoronavirus and the human host, have been brought to light in satisfactory detail. Among the emerging evidence, postulates regarding potential benefits of innate immune memory and heterologous immunity have been put under discussion. Innate immune memory entails epigenetic reprogramming of innate immune cells caused by vaccination or infections, whereas heterologous immunity denotes cross-reactivity of T cells with unrelated epitopes and bystander CD8+ activation. Familiarization of the host immune system with a certain pathogen, educates monocytes, macrophages and other innate cells into phenotypes competent for combating unrelated pathogens. Indeed, the resolution at which non-specific innate immune memory occurs, is predominant at the level of enhanced cytokine secretion as a result of epigenetic alterations. One vaccine whose non-specific effects have been documented and harnessed in treating infections, cancer and autoimmunity, is the Bacillus Calmette–Guérin (BCG) vaccine currently used for immunization against pulmonary tuberculosis (TB). The BCG vaccine induces a diverse cytokine secretion profile in immunized subjects, which in turn may stimulate epigenetic changes mediated by immunoreceptor signalling. Herein, we provide a concise summarization of previous findings regarding the effects of the BCG vaccine on innate immune memory and heterologous immunity, supplemented with clinical evidence of the non-specific effects of this vaccine on non-mycobacterial infections, cancer and autoimmunity. This interpretative synthesis aims at providing a plausible immunological and immunogenetic model by which BCG vaccination may, in fact, be beneficial for the current efforts in combating COVID-19.

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 almost no 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 1 in Montenegrin territorial waters. Records of juveniles, subadults and adults are reported. The number of described records and available data on HSI/BMI calculations points out that the living conditions are probably most favoured in the area off the Kornati archipelago (central Adriatic Sea), compared to the habitats in the Southern Adriatic where the populations might have significantly lower density. Due to the non-systematic research and non-probabilistic data collection, it is difficult to establish with certainty whether greater number of records in the continental shelf is just an ostensible phenomenon. This article is protected by copyright. All rights reserved.

The very first finding of the Pelagic stingray, Pteroplatytrygon violacea (Bonaparte, 1832) (Elasmobranchii: Myliobatiformes: Dasyatidae), in Albanian seas is reported in this paper. Female specimen was recorded in August 2021 at Gjiri i Vlorës at the depth of 25 m and was collected for further examination. The specimen measured 43.18 cm WD, and 101 cm in TL and weighted 2.730 g in total weight. There were 25 upper tooth rows and 23 lower tooth rows, which is less than previously described for this species. No gross pathological changes were observed, nor parasites. Although there were no previous reports in the territorial waters of Albanian territorial waters of the southern Adriatic and northern Ionian Seas, it can be attributed to the lack of studies and lack of proper monitoring in fisheries. Despite importance of the record on the state level, based on our regional research we believe that the Pelagic stingray is not rare species and could be encountered in waters not too far offshore across the entire Adriatic and Ionian Seas, including the Albanian territorial waters.

Melanomacrophages of fish are commonly explored as biomarkers of water pollution and are considered to be sensitive albeit non-specific health indicators in water ecosystems. Sharks as long living marine species are good sentinel species. This study presents morphometric data for splenic and hepatic melanomacrophages (MMC), and observed histopathology in ten lesser-spotted catsharks, Scyliorhinus canicula (L.), one of the most abundant shark species in the eastern Adriatic Sea. At necropsy, we collected random tissue samples from liver, brain, gallblader, pancreas, spleen, kidney, gills, entire digestive system, thyroid gland, rectal gland, entire urogenital (male samples) and genital system (female samples). Collected tissue samples were routinely processed and stained with hematoxylin-eosin, Periodic Acid-Schiff, and Masson Trichrome for microscopic examinations and morphometry. There was a minimal number of histopathological lesions in the examined sharks, but morphometric values reported herein were three folds higher than in previous studies in free-ranging sharks. Studies on larger numbers of sharks are needed to elucidate the biological significance of our finding in the context of population decline of the lesser-spotted catshark.

Melanomacrophages of fish are commonly explored as biomarkers of water pollution and are considered to be sensitive albeit non-specific health indicators in water ecosystems. Sharks as long living marine species are good sentinel species. This study presents morphometric data for splenic and hepatic melanomacrophages (MMC), and observed histopathology in ten lesser-spotted catsharks, Scyliorhinus canicula (L.), one of the most abundant shark species in the eastern Adriatic Sea. At necropsy, we collected random tissue samples from liver, brain, gallblader, pancreas, spleen, kidney, gills, entire digestive system, thyroid gland, rectal gland, entire urogenital (male samples) and genital system (female samples). Collected tissue samples were routinely processed and stained with hematoxylin-eosin, Periodic Acid-Schiff, and Masson Trichrome for microscopic examinations and morphometry. There was a minimal number of histopathological lesions in the examined sharks, but morphometric values reported herein were three folds higher than in previous studies in free-ranging sharks. Studies on larger numbers of sharks are needed to elucidate the biological significance of our finding in the context of population decline of the lesser-spotted catshark.

Background To date there is scarce published evidence reporting the dual blood supply reaching anterior papillary muscle (APM), which descends from both major coronary arteries. Such a vascular configuration can prevent the dysfunction of right ventricular entire valvular system in case of the occlusion of proximal part of either right coronary artery (RCA) or left coronary artery (LCA). The aim of our study was to determine the vascular pattern of APM blood supply which originates from two main coronary arteries, in the context of the APM and septomarginal trabecula (SMT) topography. Methods The study was carried out using tissue obtained from 36 human hearts. The material was divided into four morphological types of SMT/APM arrangement. Vascularization and blood supply pattern of papillary muscle was investigated following the analysis of multiple tissue cross sections. The origin of APM arterial supply was traced back to both main coronary arteries. Cross-sectional area of the arteries was estimated at the base of APM and compared within mixed male-female population, aged 18–76. Results We noted that as much as 78% of entire APM material had a blood supply vasculature originating from both LCA and RCA branches. In contrast, 22% of cases APM was supplied by a single coronary artery, while in each case it proved to be LCA. We have never found APM arterial supply provided exclusively by RCA. In case of double AMP blood supply an average of total cross-section area of the arteries branching from LCA, was noted to be in excess of two and a half times bigger in type III and more than two times bigger in type IV, as compared with the arteries originating from RCA. Conclusions Our research confirm the possibility of double blood supply which vascularizes APM, but the finding does not necessarily apply in all cases. However, APM seems to be predominantly vascularized by arteries deriving from LCA, regardless of their morphological type.