Biology subjects

Benestan, L. M.

Publications and source records attributed to Benestan, L. M..

5 recordsLinked to original sources

bioRxiv2026

Female site fidelity and repeated pairings across years in bull sharks (Carcharhinus leucas) inhabiting Fiji waters

Understanding relatedness in sharks is challenging due to uncertainty in distributions, low population densities and difficulties in sampling across life stages. In Fiji, bull sharks (Carcharhinus leucas), with an effective population size estimate of [~]258, aggregate at the Shark Reef Marine Reserve (SRMR), but gravid females disperse at the end of the year to give birth in adjacent rivers. Questions remain regarding reproductive connectivity, female returns across years, and kinship structure. Using population genomics on 296 bull sharks across age classes (neonates, young-of-the-year, juveniles, and adults) collected over a decade at the SRMR and in three adjacent rivers, we assessed familial connections. Direct genetic links, including first- and second-degree relationships, connected SRMR adults with young age classes in the Navua and Rewa rivers, providing evidence of reproductive connectivity. Within rivers, genetic similarities across cohorts revealed reproductive philopatry. Remarkably, several individuals sampled years apart were assigned to the same sire-dam pairs, indicating repeated pairings across breeding seasons. However, the few related links detected between the SRMR and the rivers may reflect incomplete sampling. Altogether, bull shark reproduction in Fiji seems influenced by reproductive philopatry and repeated pairings, suggesting added complexity in their reproductive behaviour.

ecology↗

bioRxiv2026

The biogeography of the stripped Venus clam, Chamelea gallina, in the Mediterranean Sea indicates limited gene flow and shows evidence of local adaptation.

AimTo assess how biogeographic barriers and environmental heterogeneity shape connectivity and local adaptation in the striped Venus clam (Chamelea gallina), a commercially exploited bivalve in the Mediterranean Sea. LocationNortheast Atlantic (Gulf of Cadiz) and Mediterranean Sea (Alboran, Balearic, Tyrrhenian and Adriatic regions). TaxonChamelea gallina (Bivalvia: Veneridae). MethodsWe analysed genome-wide single nucleotide polymorphisms (SNPs) from 226 individuals sampled across six regions (Gulf of Cadiz, Alboran Sea, Balearic Sea, Ebro Delta, Tyrrhenian Sea and Adriatic Sea) using a seascape genomic framework. Population structure was inferred using both putatively neutral and adaptive loci. Genotype-environment associations were tested against key oceanographic variables, including sea surface temperature, salinity and nutrient availability. ResultsNeutral loci revealed weak genetic differentiation, consistent with substantial gene flow across most of the species range. In contrast, putatively adaptive loci uncovered pronounced genetic structure that corresponded closely to major Mediterranean biogeographic regions, particularly the Adriatic Sea, the Gulf of Cadiz and western-central Mediterranean basins. Significant associations were detected between genetic variation and environmental gardients, with several candidate adaptive SNPs located within coding regions, suggesting functional responses to spatially heterogeneous conditions. Main conclusionsOur results demonstrate that local adaptation can generate biologically meaningful population structure in C. gallina despite high levels of connectivity inferred from neutral markers. This decoupling between neutral and adaptive variation highlights the importance of integrating adaptive genomic information into biogeographic inference. Recognizing environmentally driven genetic differentiation is essential for defining robust management units and for improving the long-term sustainability and resilience of C. gallina fisheries under increasing anthropogenic pressure and climate change.

evolutionary biology↗

bioRxiv2026

Lessons from local ecological knowledge: cumulative stressors and governance constraints in Spanish clam fisheries

Spanish clam fisheries have contracted sharply over the past two decades, with repeated closures and declining landings affecting coastal livelihoods. Using local ecological knowledge (LEK), we examine how fishers, fishers guild leaders and regional managers interpret (i) ecological change and (ii) the institutional conditions shaping management outcomes in Spains main clam fisheries, focusing on wedge clam (Donax trunculus), striped venus clam (Chamelea gallina) and smooth clam (Callista chione). We conducted 94 semi-structured interviews (April 2024-August 2025) across the Spanish Mediterranean and the south Atlantic coast (Catalonia, Valencian Community, Balearic Islands, Murcia and Andalusia). Stakeholders characterised declines as a cumulative process driven by interacting stressors: climate variability and extremes, coastal habitat alteration, pollution, episodic disease events and fishing pressure intensified by illegal extraction and informal marketing. Governance assessments were predominantly negative, emphasising fragmented authority across administrative scales, delayed or reactive measures, uneven rules among gears exploiting shared stocks, limited user influence in decision-making, and chronic monitoring and enforcement gaps, especially for shore-based fisheries operating outside port-based control points. Overall, LEK closely aligns with scientific evidence on cumulative stressors, suggesting that persistent declines reflect less a lack of ecological understanding than institutional constraints that hinder timely, legitimate and enforceable responses. Policy priorities include climate-adaptive harvest rules linked to environmental indicators, co-produced monitoring, strengthened traceability and compliance, harmonised rules across gears and management units, and improved cross-sector coordination to reduce conflict and safeguard nearshore habitats. HighlightsO_LIStakeholders across Spain describe clam declines as the outcome of interacting ecological, climatic, and governance stressors rather than as the consequence of isolated drivers. C_LIO_LIPerceived drivers differ regionally: climate- and habitat-related pressures dominate the Mediterranean, while effort, illegal fishing, and market dynamics are more salient in the Gulf of Cadiz. C_LIO_LIMost interviewees view management and governance as ineffective, citing fragmented authority, uneven rules among gears and regions, and weak enforcement. C_LIO_LIInformal practices (off-auction sales and poaching) are repeatedly identified as mechanisms undermining legitimacy, traceability, and effort controls--particularly in nearshore wedge clam fisheries. C_LIO_LIPolicy pathways include harmonising cross-scale rules, strengthening monitoring and compliance, and institutionalising co-management that integrates LEK with science. C_LI

ecology↗

bioRxiv2025

Governing the decline: clam fisheries and the challenges of decentralized management across the western Mediterranean and Gulf of Cadiz (Spain).

Over the past four decades, clam fisheries along the Mediterranean and Atlantic coasts of Spain have exhibited significantly different ecological and governance trajectories. This study synthesises long-term landing data from 1993 to 2024 with a systematic review of regional legislation to explore how management frameworks influence the resilience of fisheries. In the northwest Mediterranean, which includes Catalonia, the Valencian Community, the Balearic Islands, and Murcia, fisheries have experienced synchronous declines, a consequence of overexploitation, fragmented governance, and reactive, top-down regulation. In contrast, Andalusia, encompassing both the Atlantic and Alboran Sea coasts, has demonstrated more resilient trajectories, bolstered by greater ecological productivity and the adoption of adaptive governance strategies since the 2010s. In this region, the implementation of gear-specific management plans, rigorous scientific monitoring (including satellite tracking), and prompt administrative responses has facilitated more sustainable exploitation. Our findings highlight the necessity of aligning governance with ecological connectivity and integrating adaptive co-governance structures that engage fishers to safeguard the future of small-scale fisheries. More broadly, this research emphasises the need for coordinated superregional or national management frameworks that incorporate ecological knowledge, promote stakeholder participation, and allow for timely regulatory adaptation.

ecology↗

bioRxiv2025

Temporal seascape genomics identifies evolutionary significant units in a highly exploited marine resource, the wedge clam Donax trunculus.

Clam fisheries along the Spanish coast have declined unevenly, while stock management often follows political rather than biological boundaries. To inform conservation and fishery management, this study used temporal seascape genomics to assess population structure, genetic diversity and effective population size (Ne) in the wedge clam Donax trunculus across approximately 2,000 km of the Iberian coast. Using 7,830 putatively neutral and 649 candidate outlier SNPs from 331 individuals, the analyses confirmed broad Atlantic-Mediterranean differentiation, identified the Alboran Sea as a distinct genetic unit, and revealed finer-scale Atlantic substructure. Temporal genomic comparisons showed that population structure remained largely stable over the study period, although genetic diversity changed in a site-specific manner across fishing areas. Genotype-environment analyses indicated that spatial structure explained more genomic variation than environmental predictors, especially after accounting for spatial- environmental collinearity. Overall, the results show that temporal seascape genomics can distinguish persistent biogeographic structure from short-term, local genomic change in exploited marine invertebrates, providing a robust framework for biologically informed stock delineation. The genetically distinct groups identified here should therefore be considered separately in conservation, fishery management and any future reinforcement planning.

evolutionary biology↗