This study presents the first documented case of healing in the deep-sea sharpnose sevengill shark (Heptranchias perlo), a poorly understood species in the Mediterranean Sea. A juvenile specimen that sustained a traumatic mandibular fracture with extensive soft-tissue avulsion, which likely resulted from de-hooking during a previous longline capture, was retrieved dead by a bottom trawler in the southern Adriatic Sea. Gross pathological and radiographic examinations confirmed that the injury remained isolated to the mandibular region, with no abnormalities detected in the splanchnocranium or the musculoskeletal system. Evidence of advanced healing and scar tissue formation was observed, and stomach content analysis revealed active feeding had occurred despite the injury, suggesting that severe mandibular trauma may not have impaired prey capture or consumption. The documented healing indicates that survival following severe mandibular injury and longline capture is possible in H. perlo, in contrast to the high at-vessel mortality previously recorded for this species in bottom-trawl fisheries. However, this conclusion remains tentative, and our findings highlight the need for further research into the recovery capacity of deep-sea shark species that are impacted by commercial fishing, which is crucial for informing conservation strategies and fishery management.

Abstract Developmental abnormalities in elasmobranchs (sharks and rays) are rarely documented, with reported cases primarily involving fin or cranial deformities. Monozygotic twinning, the formation of identical twins from a single zygote, is particularly rare in these species and has been observed overwhelmingly in viviparous elasmobranchs. Here, we document a rare case of monozygotic twinning in an oviparous shark, the Small‐spotted Catshark Scyliorhinus canicula (Linneaus, 1758). This case was characterized by two embryos connected to a single yolk sac via separate yolk stalks within the egg capsule. The embryos exhibited normal development until mortality at developmental Stage 31 (Ballard et al., 1993) or stage 4 (Musa et al., 2018), likely due to stressors such as oxidative stress and allostatic overload, resulting from shared resources within the capsule. This is the first confirmed instance of mortality in monozygotic elasmobranch twins, highlighting the plausible challenges of polyembryony in oviparous elasmobranchs. These findings underscore the importance of understanding reproductive abnormalities and their implications for fecundity, particularly in light of ongoing anthropogenic pressures that threaten elasmobranch populations globally.

This study documented the first evidence of healing and long‐term survival of blackmouth catsharks (Galeus melastomus) following traumatic mandibular fractures and associated soft tissue avulsions that resulted from previous captures on deep‐sea longlines. All sharks were actively feeding, despite acute and healed lesions, which suggests that such severe trauma did not impair feeding. Additionally, one female with a healed lesion and three developed eggcases indicated that reproduction was unaffected. Magnetic resonance imaging (MRI) showed no other alterations in the chondrocranium, splanchnocranium, or broader skeletomuscular system and major viscera. Although the small sample size does not fully represent postrelease survival for the species after capture in longline fisheries, the resilience observed was significant for conservation and fisheries management, which underscores the need for further research.

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.