Biology subjects

Lamarins, A.

Publications and source records attributed to Lamarins, A..

3 recordsLinked to original sources

bioRxiv2026

Extremely low effective population size in a captive-bred population: partial mitigation through management practices

1Effective population size (Ne) is a critical parameter for evaluating the evolutionary and persistence potential of endangered populations and for designing sustainable conservation strategies. Captive breeding and release programs are widely used across taxa to reduce risk of extinction when natural reproduction is insufficient or no longer possible, making it essential to assess their consequences. We used the case study of the landlocked Saimaa salmon (Salmo salar), one of the most critically en-dangered salmonid populations in Europe, with unique evolutionary significance due to its isolation from other populations since the last glaciation. Using long-term demographic data (1969-2024) from wild-caught founders of a captive breeding and release program, we estimated the effective population size under multiple scenarios of variance in reproductive success. Across scenarios, Ne ranged from 33 to 81 individuals, representing 32%-75% of the census size. Captive breeding practices aimed at equalizing parental contributions during fertilization and early life stages increased Ne by 12% compared to natural reproductive conditions. However, variation in survival after early developmental stages, typically beyond direct management control, remained a key determinant of Ne. Despite recent increases in the number of founders, the population remains genetically vulnerable due to historical bottlenecks. These results highlight that while captive breeding programs can partially mitigate genetic risks, their effectiveness depends critically on both controlled and uncontrolled sources of variance in reproductive success. Strengthening such programs may require combining breeding management with habitat restoration and, where appropriate, genetic rescue to ensure the long-term evolutionary potential of such unique and endangered populations.

evolutionary biology↗

bioRxiv2024

Eco-evolutionary consequences of selective exploitation on metapopulations illustrated with Atlantic salmon

While the eco-evolutionary consequences of dispersal and exploitation are increasingly recognized, consideration of these effects and how they interact for management and conservation remains limited. We addressed this gap by examining population exploitation within a metapopulation framework, using Atlantic salmon as a case study. We compared eco-evolutionary consequences of alternative exploitation strategies by incorporating selective exploitation based on life history traits and spatial dimension of exploitation (i.e., whether populations were net exporter or importer of individuals). We used a demo-genetic agent-based model to examine demographic and evolutionary consequences of these strategies across a gradient of population-specific exploitation rates. At the metapopulation scale, we found both lower abundance and earlier sexual maturation with increasing exploitation, particularly when fishing was selective on larger individuals. The spatial selectivity of exploitation had an overall additional detrimental effect on metapopulation performance and fisheries yield, and induced stronger evolutionary changes than when exploitation was evenly spread over all populations. We discuss the implications of metapopulation functioning for species management and how considering dispersal patterns and intensity might change how we apply harvest. Nevertheless, our findings suggest that the safest approach remains to distribute exploitation efforts evenly across all populations, especially in the absence of variation in intrinsic productivity and with the dispersal rates and spatial configuration simulated. However, this strategy might not completely prevent negative consequences at the local scale. Therefore, we advise managers to critically assess the relevance of our results and dispersal assumptions in the specific cases they may have to deal with.

ecology↗

bioRxiv2024

Dispersal and gene flow in anadromous salmonids: a systematic review

Dispersal is a ubiquitous ecological process that has been extensively studied in many plants and animals. Anadromous salmonids are an interesting system for examining dispersal, in part because of their well-known philopatric behavior, but also because of the conservation challenges related to the dispersal of hatchery-origin fish. Building on earlier work, we provide an updated systematic review of dispersal and gene flow in anadromous salmonids. In particular, we compared studies on dispersal of anadromous salmonids from wild and hatchery origins, including studies providing estimates of dispersal rates, observations of dispersal, and results from modelling studies. We reviewed 228 studies and found these were unevenly distributed among species, with Atlantic salmon, Chinook salmon, and sea trout being well-represented. Our results showcase considerable variability in estimated dispersal rates within and across studies, which is likely related to the different methodologies, dispersal propensities across species and populations, and spatial extents considered. Overall, our results confirmed a higher tendency of hatchery fish to disperse relative to wild fish, but we also found some variation across species that warrants further study. Moreover, we found that dispersal propensity tended to decline exponentially with distance, and that the drivers of dispersal varied considerably among studies. Additionally, we highlight various facets of dispersal captured across this suite of studies, including variation in terminology, methods and metrics for characterizing dispersal, and the spatio-temporal scales considered. Finally, our review revealed that few studies considered, and even fewer assessed, the implications of dispersal for the conservation and management of anadromous salmonids.

ecology↗