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Groupers are marine fishes particularly vulnerable to overexploitation owing to their reproduction‐related traits. The dusky grouper Epinephelus marginatus is classified as 'Endangered' in the Mediterranean Sea, where protection measures have proven critical for allowing population recovery and persistence of the species. However, knowledge gaps remain regarding its reproductive behaviours and spawning sites. As with other grouper species, the dusky grouper is known to produce courtship‐associated sounds, which were validated in captivity, but no study has ever established a link between sound production and observed behaviours in the wild.This study aims to characterize, both visually and acoustically, the behavioural patterns of wild dusky grouper, thus specifically linking visual courtship behaviours to the associated sound production. Visual as well as passive acoustic methods were employed at two presumptive spawning sites within a Mediterranean Marine Protected Area (MPA) in the north‐western Mediterranean Sea over two consecutive summer seasons (2017 and 2018).The temporal patterns of sound production showed site specificity over the month in which reproductive activity was most intense. Courtship calls were mostly recorded around sunset at both study sites and were significantly associated with visual reproductive behaviours. Results also indicated a temporal partitioning in the acoustic activity of the species, with different sound types being recorded at distinct times of the day, likely corresponding to the occurrence of various behaviours during those periods.These findings have important implications for identifying and monitoring dusky grouper spawning sites using passive acoustic methods, therefore providing valuable information for the development, implementation, and/or enforcement of effective conservation measures therein. [ABSTRACT FROM AUTHOR]

Assessing individuals' abundance, residency (presence at a site within a certain period) and site fidelity (tendency to return to the same site in subsequent seasons or years) is crucial for evaluating and improving the effectiveness of spatial conservation/management measures regarding ecologically and socio-economically valuable species. Using underwater visual census (UVC) and photo-identification (photo-ID) techniques, we estimated the abundance, residency and site fidelity of the dusky grouper, Epinephelus marginatus, at two protected sites within the Tavolara-Punta Coda Cavallo Marine Protected Area (Sardinia, Italy) in the summers of 2017-2018. The scope and spatio-temporal resolution of the study was extended by involving volunteer recreational divers in the photo collection. Grouper mean densities varied significantly across sampling dates, with a significant variability between the 2 years and the two investigated sites. At least 94 grouper visited the study sites in the summers of 2017-2018 based on the analysis of 968 high-quality photos using a semi-automated software to photo-identify individuals. Overall, the most frequently sighted grouper was recorded on 32 different days and 21 individuals (22%) identified in 2017 were re-sighted in 2018. The participation of volunteer recreational divers helped detect the inter-site (3.5-4 km apart) movements of a female and a male, supporting previous findings regarding the occurrence of reproduction-related movements. This study provides novel insights into the residency and site-fidelity patterns of the dusky grouper, and its small-scale movements probably related to reproduction. Specifically, we provide indications that effective protection from fishing should encompass the entire area used by grouper for reproductive movements., Author(s): Elena Desiderà [sup.1] [sup.2] [sup.5] , Egidio Trainito [sup.7] , Augusto Navone [sup.3] , Rémi Blandin [sup.8] , Luana Magnani [sup.9] , Pieraugusto Panzalis [sup.3] , Carlotta Mazzoldi [sup.1] [...]

Globally, elasmobranch species have been declining in abundance due to fishery activities. This conservation issue calls for effective management strategies and increasing efforts to protect these species. The declining status of elasmobranchs in the Mediterranean Sea is alarming as well. Reversing such dramatic trends requires tackling fishing pressure using multiple methods, including a fine‐tuned spatial resolution in conservation strategies incorporating robust evidence on species spatial use at different life stages and its overlap with fishing pressure. In particular, a scientifically sound identification of nursery grounds is crucial to define key spatial management targets promoting the recruitment of such depleted species.Here we focused on the sandbar shark (Carcharhinus plumbeus), listed as endangered by the IUCN, and on the nursery of its early juveniles such as newborns (i.e. a few months old) and young‐of‐the‐year individuals (i.e., < 1 year old), both characterized by a total length below 71 cm. First, by monitoring a small‐scale fishery fleet in the North‐Western Adriatic Sea, we unambiguously identified a local multiyear nursery site for early juveniles of this species.Then, we combined such novel information with a bibliographic review on the presence and absence of early juveniles across Mediterranean regions to construct a species distribution model predicting favourable nursery areas throughout the entire Mediterranean Sea. To do so, a Bayesian approach was applied to construct a generalized linear model with spatial effect estimated by a Gaussian random field (INLA‐SPDE). Model‐based inference indicates that, in summer, which is the main pupping season, important nursery areas for this species are found along the North‐Western coast of the Adriatic Sea, in the coastal area of the Gulf of Gabes, and in the Gulf of Iskenderun (North‐Eastern Levantine Sea).Synthesis and applications: These key areas should be prioritized to apply conservation measures to foster the recruitment of this species since intense fishing activities were also documented. Model predictions also allowed to determine where unknown nursery grounds may potentially occur, a valuable information to direct future monitoring efforts and clarify any further occurrence of nursery areas. [ABSTRACT FROM AUTHOR]