Unsupervised estimation of the age at sea departure of Atlantic salmon using magnesium, manganese, and zinc otolith chemistry.

Investigating the age at sea departure of returning Atlantic salmon is critical to better understand the role of emigration timing in survival. Among the methods available, the use of otolith chemistry can be challenging in anadromous fish, as the elements frequently used (i.e.

Quantifying larval dispersal portfolio in seabass nurseries using otolith chemical signatures.

The temporal asynchronies in larvae production from different spawning areas are fundamental components for ensuring stability and resilience of marine metapopulations. Such a concept, named portfolio effect, supposes that diversifying larval dispersal histories should minimize the risk of recruitment failure by increasing the probability that at least some larvae successfully settle in nursery. Here, we used a reconstructive approach based on otolith chemistry to quantify the larval dispersal portfolio of the European seabass, Dicentrarchus labrax, across six estuarine nursery areas of the northeast Atlantic Ocean.

Juvenile downstream migration patterns of an anadromous fish, allis shad (Alosa alosa), before and after the population collapse in the Gironde system, France.

Diadromous fish have exhibited a dramatic decline since the end of the 20th century. The allis shad (Alosa alosa) population in the Gironde-Garonne-Dordogne (GGD) system, once considered as a reference in Europe, remains low despite a fishing ban in 2008. One hypothesis to explain this decline is that the downstream migration and growth dynamics of young stages have changed due to environmental modifications in the rivers and estuary.

Metal localisation in gastropod shells: New insights from mass spectrometry techniques.

Gastropod shells are calcified structures made of several crystal layers. They grow throughout the lifecycle of mollusks by integrating some of the chemical elements present in their environment, including metals. This characteristic means mollusks can be useful bioindicators of metal exposure.

Heterogeneity of otolith chemical composition from two-dimensional mapping: Relationship with biomineralization mechanisms and implications for microchemistry analyses.

Although otoliths are widely used as archives to infer life-history traits and habitat use in fishes, their biomineralization process remains poorly understood. This lack of knowledge is problematic as it can lead to misinterpretation of the different types of signals (e.g.

Effect of metabolic rate on time-lag changes in otolith microchemistry: an experimental approach using Salmo trutta.

Ecologists have long been interested in relevant techniques to track the field movement patterns of fish. The elemental composition of otoliths represents a permanent record of the growing habitats experienced by a fish throughout its lifetime and is increasingly used in the literature. The lack of a predictive and mechanistic understanding of the individual kinematics underlying ion incorporation/depletion limits our fine-scale temporal interpretation of the chemical signal recorded in the otolith.

European flounder foraging movements in an estuarine nursery seascape inferred from otolith microchemistry and stable isotopes.

Despite the importance of estuarine nurseries in the regulation of many fish stocks, temporal and spatial movements and habitat use patterns of juvenile fish remain poorly understood. Overall, combining several movement metrics allowed us to characterize dispersal patterns of juvenile flounder, Platichthys flesus, along an estuarine seascape. Specifically, we investigated otolith microchemistry signatures (Sr:Ca and Ba:Ca ratios) and stable isotope ratios (δC and δN) in muscles of these juveniles, during three consecutive years to assess inter-annual fluctuations in their home range and isotopic niches.

Specific pathways for the incorporation of dissolved barium and molybdenum into the bivalve shell: an isotopic tracer approach in the juvenile Great Scallop (Pecten maximus).

Dissolved barium and molybdenum incorporation in the calcite shell was investigated in the Great Scallop Pecten maximus. Sixty six individuals were exposed for 16 days to two successive dissolved Ba and Mo concentrations accurately differentiated by two different isotopic enrichments (⁹⁷Mo, ⁹⁵Mo; ¹³⁵Ba, ¹³⁷Ba). Soft tissue and shell isotopic composition were determined respectively by quantitative ICP-MS (Inductively Coupled Plasma Mass Spectrometer) and laser ablation--ICP-MS.