Determining population structure and connectivity through otolith chemistry of stout whiting, Sillago robusta

Abstract

Connectivity in aquatic systems allows for the delivery of resources to and from habitats and the exchange of genetic material (Brookes et al., 2015;Cury, 1994). For fish populations, connectivity includes dispersal or movement of individuals as eggs, larvae, juveniles or adults (Calò et al., 2013). Assessing the structure of fish populations is critical in understanding connectivity patterns, while also allowing for appropriately targeted management strategies for heavily fished species (Avigliano et al., 2017;Walters & Martell, 2004). Population structure and connectivity have previously been analysed using both artificially applied and naturally occurring tagging techniques for a range of fish species.Applied tagging methods (e.g. archival tags and acoustic telemetry) have been used to determine migratory patterns and assess space use (Calò et al., 2013;Hutson et al., 2007). Archival tags incorporate environmental sensors to record movement and oceanographic data over a given time (

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

“…This study, investigating the spatial distribution and asymmetry of elemental incorporation throughout the otolith across two species of commercially important fishes, has important implications for the inferences drawn by studies of otolith chemistry. The current standard approaches to the analysis of otolith chemistry are usually transect or spot sampling (e.g., Sarakinis et al, 2022; Sturrock et al, 2015; Thomas et al, 2020). This partial sampling is commonly performed along the longest growth axis of the otolith, between the proximal and distal halves, and carries the risk, unless prior knowledge of elemental spatial distribution is used, of missing the areas of greatest concentrations in asymmetrically distributed elements, or of attributing ecological relevance to the physiological distribution of elements.…”

“…Mn studied here in both species also shows signs of seasonal or cyclical incorporation, potentially linked to migration between different temperature or salinity regimes or to physiological cycles, but future research in this direction will need to account for the strongly distal asymmetrical distribution of this element throughout the otolith. approaches to the analysis of otolith chemistry are usually transect or spot sampling (e.g., Sarakinis et al, 2022;Sturrock et al, 2015;Thomas et al, 2020). This partial sampling is commonly performed along the longest growth axis of the otolith, between the proximal and distal halves, and carries the risk, unless prior knowledge of elemental spatial distribution is used, of missing the areas of greatest concentrations in asymmetrically distributed elements, or of attributing ecological relevance to the physiological distribution of elements.…”

Strong philopatry in an estuarine‐dependent fish

“…With many fisheries‐based studies relying on trawling and manual netting procedures to collect samples (Reis‐Santos et al., 2018 ; Sarakinis et al., 2022 ), assessing relatedness within sample sets is essential to accurately infer population structure and connectivity. There is the possibility that fish caught within an estuary on the same day or from the same net haul are closely related.…”