Browsing by Issue Date, starting with "2025-09-21"
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- Revealing chronotypes across aquatic species using acoustic telemetryPublication . Martorell‐Barceló, Martina; Abecasis, David; Akaarir, Mourad; Alonso‐Fernández, Alexandre; Arlinghaus, Robert; Aspillaga, Eneko; Barcelo‐Serra, Margarida; Brevé, Niels W. P.; Davidsen, Jan G.; Gamundí, Antoni; Grau, Amalia; Hereu, Bernat; Jarić, Ivan; Kapusta, Andrzej; Lowerre‐Barbieri, Sue; Monk, Christopher T.; Nickel, Anja K.; Nicolau, María C.; Ólafsdóttir, Guðbjörg Á.; Olsen. Esben M.; Pickholtz, Renanel; Prchalová, Marie; Reubens, Jan; Říha, Milan; Knaap, Inge van der; Verhelst, Pieterjan; Villegas‐Ríos, David; Alós, JosepAcoustic telemetry offers valuable opportunities to investigate individual variability in circadian-related and other behaviours and how environmental cues shape these patterns in wild fish populations. However, this potential has not yet been fully exploited. We conducted a meta-analysis on 44 datasets from 34 distinct marine and freshwater species and different types of data (acoustic detections, depth, acceleration and positioning). Our aim was to explore the potential of acoustic telemetry in identifying chronotypes as consistent among-individual differences in circadian-related behaviours. First, we applied hidden semi-Markov models to classify individual time series into active and rest states. Subsequently, we computed two classical circadian-related behavioural traits: awakening time (as the activity onset) and rest onset (as the activity offset). Subsequently, we identified distinct phenotypes by decomposing behavioural variation into within- and among-individual components based on repeatability scores. We found evidence of distinct chronotypes in 17 species, with average repeatability scores of 0.52 for awakening time and 0.43 for rest onset, revealing that chronotypes are common in aquatic species. Our findings highlight that both the data type, particularly acceleration sensors, and the number of detections are effective tools for exploring chronotypes. Our study proposes a novel approach to characterising daily activity patterns in aquatic species, predominantly in fishes, and provides guidelines for investigating chronotypes across diverse taxa. We emphasise the promise of biotelemetry and advanced statistical models for improving our understanding of the behaviour of aquatic species and highlight the value of synthesising across large data sets collected in networks of biotelemetryprojects.
- Design of an observing system simulation experiment for the operational model of the southwestern coast of Iberia (SOMA)Publication . Mendonça, Fernando; Martins, Flávio; Bertino, LaurentObserving System Simulation Experiments (OSSEs) provide a framework in which to evaluate the impact of prospective ocean-observation networks on model forecasting performance prior to their actual deployment. This study presents the design and validation of an OSSE tailored for the operational coastal model of southern Portugal, SOMA. The system adopts the fraternal twins approach and a univariate data-assimilation scheme based on Ensemble Optimal Interpolation to update the model’s 3D temperature structure with SST. The methodology provides a flexible framework that preserves the statistical structure of real observation errors while remaining independent of SOMA. This allows straightforward transfer to other applications, thereby broadening its applicability and making it useful as a starting point in the design of observation networks beyond that presented in this case study. The OSSE experiments were compared against corresponding Observing System Experiments (OSEs) using real satellite SST products. Results show that the designed OSSE is internally consistent, sensitive to observation density, and capable of reproducing realistic correction patterns that closely match those obtained in the OSEs. These findings provide strong evidence that the SOMA OSSE system is a reliable tool for assessing the potential impact of future surface-observation strategies.