Previous studies suggest that the common bottlenose dolphin population in the Croatian Adriatic Sea is structured into distinct local communities. However, their home ranges and levels of interaction remain unknown. Dedicated boat‐based surveys were conducted seasonally, in three adjacent study sites from 2013 to 2017. Photo‐identification data were used to identify distinct local communities by relating the social structure descriptors to the home ranges of individual animals, and to determine the community home ranges and identify the levels of interactions between them. The overlaps between the home ranges of individuals (50 and 95% kernel density estimators [KDE]) were positively correlated to association strengths between them. Three distinct communities were identified by the hierarchical cluster analysis. The individuals' 95% KDE home range overlaps and association strengths were significantly higher within the three communities than between them, indicating both social and spatial segregation. The 95% KDE home ranges of the communities showed very low to no overlap. The individuals ranged mainly centrally within the home range of their respective community. The probabilities of movement, expressed as lagged identification rates, were significantly higher within than between community home ranges. However, 37 out of 1024 identified individuals were observed in more than one community home range, indicating that the communities are not isolated. Four out of the six Sites of Community Importance currently in place within the Croatian Adriatic Sea lie within the home ranges of the three local bottlenose dolphin communities. Once these sites are declared as Special Areas of Conservation, the management scheme will need to accommodate for differences in the spatial and social ecology of these communities, and environmental and anthropogenic factors acting upon them. The results of this work provide baseline information for such tailored management.

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In spring 2021, four unusual encounters with a group of false killer whales were recorded in Kvarner Bay, Northern Adriatic Sea. A minimum of five individuals, including a calf, were observed and two photos were taken corroborating species identification. These are the first reported sightings of the species in the Adriatic Sea since the mid-twentieth century. In addition, another encounter was revealed that occurred at the end of the 2000s in the same location and should be added to the list of historic observations. These reports were obtained by chance and show the importance of citizen science in obtaining data on rare marine species. The information gathered goes towards a better understanding of the distribution of the species in the Mediterranean Sea.

Summary:In order to investigate the phylogeography and population genetic structure of the South European toothcarp (Aphanius fasciatus), we analysed gene sequences of two mitochondrial markers (cytochrome b and mtDNA control region) in samples from eight localities along the eastern Adriatic coast and combined them with sequences from other Mediterranean localities. Since the South European toothcarp primarily inhabits hypersaline water bodies, it is a good model species for understanding patterns of colonization and dispersal of species adapted to variable conditions. The eastern Adriatic populations are separated into two groups of genetically related populations. The Northern group contains the populations from Sečovlje, Pag, Dinjiška, Nin and Pantan, whereas the Southern group contains the populations from Ston, Ulcinj and Narta. The majority of divergence events date back to the Pleistocene epoch and it is likely that sea level changes during glacial cycles played a significant role in shaping the recent genetic structure of this species. Our results imply pronounced intraspecific structuring of this species, whereas great environmental variations resulted in a smaller intrapopulational genetic diversity of A. fasciatus than seen in other Mediterranean fishes.Keywords: colonization; conservation priorities; divergence; evolution; genetic diversity; South European toothcarp.Estructura genética poblacional e historia demográfica de Aphanius fasciatus (Cyprinodontidae: Cyprinodontiformes) en hábitats hipersalinos del Adriático oriental Resumen: Con el objetivo de analizar la estructura genética y filogeografía de las poblaciones del fartet oriental (Aphanius fasciatus), se analizaron secuencias de genes de dos regiones mitocondriales (citocromo b y región de control del ADNmt) en individuos de ocho localidades a lo largo de la costa oriental del Adriático y de otras localidades mediterráneas. El fartet oriental habita principalmente masas de agua hipersalinas, y es una buena especie modelo para el estudio de los patrones de colonización y dispersión de especies adaptadas a condiciones variables. Los resultados de nuestro estudio muestran que las poblaciones del Adriático oriental se separan en dos grupos genéticamente relacionados. El grupo del Norte contiene las poblaciones de Sečovlje, Pag, Dinjiška, Nin y Pantan, mientras que el grupo del Sur contiene las poblaciones de Ston, Ulcinj y Narta. La mayoría de los eventos de divergencia pudiera ser que se remontaran a la época del Pleistoceno, y es probable que los cambios del nivel del mar durante los ciclos glaciales jugasen un papel importante en la estructura genética reciente de esta especie. Nuestros resultados revelan diferencias intraespecíficas pronunciadas en el fartet oriental, y por otro lado menor diversidad genética intrapoblacional como resultado de grandes variaciones ambientales en comparación con otros estudios de peces del Mediterráneo.Palabras clave: colonización; prioridades de conservación; divergencia; evolución; diversidad genética; fart...

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