Biology subjects

Alos, J.

Publications and source records attributed to Alos, J..

3 recordsLinked to original sources

bioRxiv2026

Fishing pressure induces changes in DNA methylation in genetically homogeneous marine metapopulations

Trait-selective harvesting by fisheries can impose strong selective pressures on fish populations, driving changes in life history traits affecting fisheries productivity and ecosystem functioning. While the genetic consequences of harvesting have been extensively studied, the extent to which phenotypic variation reflects genomic evolution versus environmentally-induced plasticity remains unclear. Epigenetic mechanisms, such as DNA methylation, may mediate between these processes, serving as a rapid and reversible response to the selective pressures imposed by harvesting. In this study, we implemented an improved laboratory and bioinformatics protocol, epiGBS3, to examine genomic variation and DNA methylation patterns in the marine fish Xyrichtys novacula. The study spanned three replicated geographical areas each comprising two adjacent locations: an intensively exploited fishery and a no-take Marine Protected Area (ntMPA). A nested analysis design across the three areas revealed strong gene flow and no evidence of genetic structure. Nevertheless, nucleotide diversity was significantly reduced in fisheries relative to ntMPAs. We also found that DNA methylation levels differed between protected and exploited sites after controlling for age, suggesting that fishing may influence epigenetic changes independently of fisheries-induced age-truncation effects. This represents one of the first lines of evidence that fisheries can potentially shape epigenetic variation, supporting DNA methylation as contributor to local adaptation under high gene flow and strong anthropogenic selection.

molecular biology↗

bioRxiv2025

Reliability of self-reported catch and effort data via smartphone applications in a multi-species recreational fishery

The spatial and temporal heterogeneity of recreational anglers and the challenges associated with monitoring their activities often complicate their effective management. Angler smartphone applications (apps) offer a promising digital tool for self-reporting fishing effort (E) and captures per unit of effort (CPUE). However, despite their growing use for data collection in recreational fisheries, the existing literature on their performance remains limited, raising concerns about potential biases in the collected data. Since 2019, self-reporting of E and CPUE has been mandatory for recreational fishing trips within the network of partially-protected Marine Protected Areas (MPAs) in the Balearic Islands (Spain). A regional-scale App ("Diari de Pesca Recreativa") was developed to streamline data collection. This study aimed to evaluate the Apps performance in reporting recreational fisheries data over a six-year period. Data obtained via the App (3,672 trip self-reports) were compared to data collected through a traditional method (360 on-site creel surveys). Estimates of E and CPUE were compared across datasets overall, as well as by month, fishing modality, MPA, and for key target species. Significant differences were observed for E (hours {middle dot} angler {middle dot} trip, p < 0.001) and CPUE (captures{middle dot} E-1, p = 0.001) across datasets. However, when stratified by species, month, fishing modality, and MPA, most groups showed no statistically significant differences in E and CPUE estimates. Data from the App tended to overestimate E compared to creel surveys, likely due to inaccuracies in self-reported trip durations. Conversely, creel surveys appeared to underestimate E, reflecting intrinsic biases in trip duration collection. Assuming that the true values of E and CPUE lie between the estimates derived from the App and creel surveys, integrating both methods is recommended to improve the accuracy and reliability of data. The App not only generates a higher volume of trip data but also provides a user-friendly platform for self-reporting. Moreover, it digitizes data collection, enabling automation and advanced analytics for fisheries monitoring and management of recreational fisheries.

ecology↗

bioRxiv2019

Intraspecific population admixture of a top piscivore correlates with anthropogenic alteration of freshwater ecosystems

Conservation of local genetic diversity is an important policy objective, but intraspecific genetic diversity can be transformed by natural ecological processes associated with anthropogenic changes in ecosystems. Environmental changes and a strong interconnection of drainage systems impact freshwater biodiversity from gene to population level. Populations can either become extinct or expand their range and accompanying secondary contacts can lead to genetic admixture. We investigated how the genetic population structure and the patterns of genetic admixture of Esox lucius L. (the northern pike) vary with the type of ecosystem and the integrity of the ecosystem assessed by measures under the European Water Framework Directive. The pike inhabits river, lake and brackish water ecosystems, where it is confronted with different ecological disturbances. We analysed 1,384 pike samples from the North, Baltic and Black Sea drainages and differentiated between metapopulations from each hydrogeographic region using genotypes from 15 microsatellites and mitochondrial cyt b sequences. Individual populations showed signs of genetic admixture ranging from almost zero to complete replacement by foreign genotypes. Hierarchical general linear modeling revealed a highly significant positive association of the degree of genetic admixture with decreasing ecological status. This may mean that populations in disturbed environments are more prone to influences by foreign genotypes or, alternatively, increased genetic admixture may indicate adaptation to rapid environmental changes. Regardless of the underlying mechanisms, our results suggest that anthropogenic alterations of natural freshwater ecosystems can influence genetic structures, which may lead to a large-scale reduction of intraspecific genetic diversity.

evolutionary biology↗