Dear MARMAM colleagues, We are pleased to announce that the following paper is now available online: Papale E., Ceraulo M., Gregorietti M., De Vita C., Buscaino G. (2024) Assessing the effectiveness of acoustic signals in mark-recapture studies to estimate dolphins’ population size, Current Zoology, zoae079 Abstract: Accurate estimations of animal population size are pivotal for implementing management strategies properly. Recapture technique based on sounds as a specimen identification mark has barely been used for marine mammals. However, inferring abundance estimates from acoustic methods could enhance the accuracy and precision of population size assessments. Here, we tested the possibility of using signature whistles as individual marks for estimating the size of common bottlenose dolphin (Tursiops truncatus) populations. Data were continuously collected for 326 days in 2015–2016, by using a fixed acoustic device located in the Sicily Strait (Italy). The SIGID method was applied to identify Signature Whistles Types (SWTs) over 7,000 h of recordings. Eighty SWTs were detected as long as their stereotyped fundamental frequency contours were repeated in bouts of at least 6 renditions. The mean SWTs monthly recording rate resulted in 0.19 (Standard deviation = 0.16), with 20 SWTs recorded over 5 or more different encounters (until a maximum of 30 encounters). The Jolly–Seber model (with POPAN formulation) was run in Mark software to estimate the population size. The estimated population size resulted in 171 bottlenose dolphins (95% confidence interval = 137–215). Even if the detection and identification of signature whistles required crucial precautions, and animals could be detected differently from visual techniques, the population size estimate obtained was comparable with previous results based on physical marks data. These out­comes demonstrated that signature whistles can be considered a strongly effective tool for integrating traditional mark-recapture techniques with finely estimated dolphins’ population abundances Key words: modeling methods, passive acoustic monitoring, signature whistles, specimen identification mark, Tursiops truncatus. A PDF copy of the paper can be downloaded for free from: https://doi.org/10.1093/cz/zoae079 Please do not hesitate to contact me for any question. Best, Elena -- Elena Papale, PhD Institute for the Study of Anthropogenic Impacts and Sustainability in the Marine Environment (IAS), National Research Council, Via del Mare 3, 91021 Torretta Granitola (TP) and Department of Life Science and Systems Biology University of Torino, Via Accademia Albertina 13, 10123 Torino Italy elena.papale@cnr.it elena.papale@ias.cnr.it elena.papale@unito.it