Acoustic sequences are commonly observed in many animal taxa. The vast vocal repertoire of common bottlenose dolphins (Tursiops truncatus) also includes sequences of multi-unit rhythmic signals called bray-call which are still poorly documented, both functionally and geographically. This study aimed to (1) describe, classify, and characterize series of bray-call recorded in two sites of the Mediterranean basin (Rome—Tyrrhenian Sea and Mazara del Vallo—Strait of Sicily) and (2) investigate for the existence of possible geographic differences. The acoustic analysis identified 13 different sequence types, only two detected in both study areas. The Sørensen–Dice index revealed a low degree of similarity between the sequence repertoire of the two common bottlenose dolphin sub-populations, with the Tyrrhenian being more diversified and complex than the Sicilian one. The acoustic parameters also showed variability between the study area. Different variants of the main acoustic elements composing the bray-call sequences were detected in the Tyrrhenian Sea only. The Markov-chain model demonstrated that the transition probability between acoustic elements is not uniform, with specific combinations of elements having a higher probability of occurrence. These new findings on common bottlenose dolphin bray-call sequences highlight the structural complexity of these vocalizations and suggest addressing future research on the context of emissions and the possible function(s) of such acoustic arrangements.
The current study provides new data on the known records of the Atlantic blue crab, Callinectes sapidus Rathbun, 1896, from the Maltese Islands through two ovigerous female specimens collected from Salini (Malta), a Natura 2000 site, in August 2020. Additional new records of the species were also presented from the San Leonardo River estuary, Syracuse (Sicily, Italy), in August 2022. The specimens collected from both Malta and Sicily were identified using both morphological and molecular analyses. The latter has shown that all the specimens analysed share their mitochondrial DNA barcode region with the most recorded haplotype of the same species from the Mediterranean Sea. Knowing the new distribution and range expansion records of alien species is important for the continuous monitoring of marine alien species, which is essential for the implementation of the best possible mitigation measures. This is especially relevant for C. sapidus, as it is considered one of the worst invaders of the Mediterranean Sea. Therefore, given that this alien species is edible, fishing for it may allow some control over its population size and further expansion. Knowing its distribution is crucial to inform fishers about its exact location, making such a mitigation measure more effective.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.