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Cisco (Coregonus artedi) are threatened by climate change and lake eutrophication, and their oxythermal habitat can be assessed with [T.sub.DO3], the water temperature at which dissolved oxygen equals 3 mg * [L.sup.-1]. We assessed the influence of [T.sub.DO3] on cisco habitat use, genetic diversity, diets, and isotopic niche in 32 lakes ranging from oligotrophic to eutrophic. Results showed that as [T.sub.DO3] increased, cisco were captured higher in the water column, in a narrower band, with higher minimum temperatures and lower minimum dissolved oxygen. [T.sub.DO3] was also negatively related to cisco allelic richness and expected heterozygosity, likely driven by summer kill events. Moreover, [T.sub.DO3] influenced the isotopic niche of cisco, as fish captured deeper were more depleted in [[delta].sup.13]C and more enriched in [[delta].sup.15]N compared to epilimnetic baselines. Lastly, cisco in high [T.sub.DO3] lakes consumed more Daphnia, had fewer empty stomachs, and achieved larger body size. Our work identifies specific characteristics of cisco populations that respond to climate change and eutrophication effects and provides a framework for understanding responses of other cold-water species at the global scale. Les ciscos de lac (Coregonus artedi) sont menaces par les changements climatiques et l'eutrophisation des lacs, et leur habitat oxythermique peut etre evalue a l'aide de la [T.sub.DO3], la temperature de l'eau a laquelle la concentration d'oxygene dissous est de 3 mg * [L.sup.-1]. Nous avons evalue l'influence de la [T.sub.DO3] sur l'utilisation d'habitats, la diversite genetique, les regimes alimentaires et les niches isotopiques de ciscos dans 32 lacs oligotrophes a eutrophes. Les resultats montrent que plus la [T.sub.DO3] est elevee, plus les ciscos sont captures haut dans la colonne d'eau, dans une bande plus etroite, caracterisee par de plus fortes temperatures de l'eau minimums et de plus faibles concentrations d'oxygene dissous minimums. La [T.sub.DO3] presente aussi une relation negative avec la richesse allelique et l'heterozygotie attendue des ciscos, vraisemblablement modulee par des episodes estivaux de mortalite. En outre, la [T.sub.DO3] influence la niche isotopique des ciscos, les poissons captures a plus grande profondeur etant plus appauvris en [[delta].sup.13]C et plus enrichis en [[delta].sup.15]N que les valeurs de reference epilimniques. Enfin, les ciscos dans les lacs de forte [T.sub.DO3] consomment plus de Daphnia, atteignent de plus grandes tailles du corps et sont caracterises par une frequence moindre d'estomacs vides. Nos travaux cernent des caracteristiques de populations de ciscos qui reagissent aux changements climatiques et aux effets de l'eutrophisation et ils offrent un cadre pour mieux comprendre les reactions d'autres especes d'eau froide a l'echelle planetaire. [Traduit par la Redaction], Introduction Cisco (Coregonus artedi) are a cold-water pelagic fish found in many North American lakes, and provide an important energetic link to pelagic energy sources for gamefish such as walleye [...]

Objective: A genetically distinct strain of Walleye Sander vitreus (southern Minnesota strain [SMS]) persists in southern Minnesota lakes despite decades of stocking more easily obtained strains from outside of the region. Because of the regional performance advantage inferred by this persistence, we conducted in situ experiments to compare survival and stocking cost of SMS Walleye fry against those of a frequently stocked northern Minnesota strain (Mississippi headwaters strain [MIS]) to determine whether it is beneficial to expand SMS fry stocking in lieu of historic practices. Methods: We conducted four paired stockings of oxytetracycline‐marked SMS fry and MIS fry into six southern Minnesota lakes and then sampled the fish as fall fingerlings during 2018, 2019, 2021, and 2022. We then used fluorescent microscopy and parentage‐based tagging techniques to discern the stocked strains for comparison of growth and survival. We also obtained production and stocking cost data from agency records to calculate relative stocking costs. Result: By the end of their first summer, SMS Walleye from all but two stockings exhibited higher survival than MIS Walleye. Despite higher initial costs to produce SMS fry, their higher survival to fall fingerlings made the stocking of SMS fry more cost effective than MIS fry stocking. Natural reproduction was also identified in several stocked lakes, most of which consisted of either high or increasing levels of SMS ancestry. Conclusion: A local strain can outperform nonlocal strains at a level that can overcome additional costs of developing a new egg source. In addition, natural reproduction of local‐strain Walleye may reduce or eliminate the need for future stocking. Impact statementWe show that a local Walleye strain can outperform nonlocal strains at a level that can overcome additional costs of developing a new egg source. In addition, higher natural reproduction of the local strain may reduce or eliminate the need for future stocking. [ABSTRACT FROM AUTHOR]

Abstract: The inception of a hatchery program to rebuild a naturalized steelhead (Oncorhynchus mykiss) population in Minnesota waters of Lake Superior gave us the rare opportunity to monitor the success [...]

The spread of aquatic invasive species typically occurs through a combination of natural and human mediated dispersal. For many aquatic invasive species, natural dispersal is limited to aquatic corridors connecting habitat. In contrast, human transport may facilitate more distant dispersal and transport among disconnected waterbodies. Genetic information can serve as a powerful tool to track invasion histories and identify both the sources and mechanisms of invasive species dispersal. We used genetic information to understand invasion history and dynamics of expanding northern pike invasion in the Columbia River basin. Results indicate that the initial introduction of northern pike into the Pend Oreille River (in eastern Washington State) resulted from human transport of fish, not dispersal from established populations upstream. Subsequent reproduction and natural dispersal from the Pend Oreille River resulted in downstream expansion of northern pike into Lake Roosevelt, a reservoir within the mainstem Columbia River. These results highlight the need for a holistic approach to suppression of invasive species. Immediate efforts must address the biological mechanisms of natural dispersal. Sustained suppression and eradication must take a broad approach that includes coordination between management agencies, as well as policy and public outreach aimed at prevention of repeated human transport events. The genetic database created from this study has already been used to eliminate potential source populations for new northern pike invasions in Washington State outside the Columbia River basin. This highlights the utility of genetic monitoring for both immediate and long-term applications to managing aquatic species invasions. [ABSTRACT FROM AUTHOR]

Effective population size ([N.sub.e]) of a natural fish population was estimated from temporal changes in allele frequencies at seven microsatellite loci. Use of a historical collection of fish scales made it possible to increase the precision of estimates by increasing the time interval between samples and to use an equation developed for discrete generations without correcting for demographic parameters. Estimates of [N.sub.e] for the time intervals 1961-1977 and 1977-1993 were 35 and 72, respectively. For the entire interval, 1961-1993, the estimate of [N.sub.e] was 48 when based on a weighted mean derived from the above two estimates or 125 when calculated from 1961 and 1993 samples only. Corresponding ratios of effective size to adult census size ranged from 0.03 to 0.14. An [N.sub.e] of 48 over a 32-year period would imply that this population lost as much as 8% of its heterozygosity in that time. Results suggest the potential for using genetic methods based on microsatellite loci data to compare historical trends in [N.sub.e] with population dynamic parameters. Such comparisons will help to evaluate the relationship between genetic diversity and long-term persistence of natural populations.

Few studies have examined capture and extraction methods for environmental DNA (eDNA) to identify techniques optimal for detection and quantification. In this study, precipitation, centrifugation and filtration eDNA capture methods and six commercially available DNA extraction kits were evaluated for their ability to detect and quantify common carp (Cyprinus carpio) mitochondrial DNA using quantitative PCR in a series of laboratory experiments. Filtration methods yielded the most carp eDNA, and a glass fibre (GF) filter performed better than a similar pore size polycarbonate (PC) filter. Smaller pore sized filters had higher regression slopes of biomass to eDNA, indicating that they were potentially more sensitive to changes in biomass. Comparison of DNA extraction kits showed that the MP Biomedicals FastDNA SPIN Kit yielded the most carp eDNA and was the most sensitive for detection purposes, despite minor inhibition. The MoBio PowerSoil DNA Isolation Kit had the lowest coefficient of variation in extraction efficiency between lake and well water and had no detectable inhibition, making it most suitable for comparisons across aquatic environments. Of the methods tested, we recommend using a 1.5 μm GF filter, followed by extraction with the MP Biomedicals FastDNA SPIN Kit for detection. For quantification of eDNA, filtration through a 0.2-0.6 μm pore size PC filter, followed by extraction with MoBio PowerSoil DNA Isolation Kit was optimal. These results are broadly applicable for laboratory studies on carps and potentially other cyprinids. The recommendations can also be used to inform choice of methodology for field studies. [ABSTRACT FROM AUTHOR]

ABSTRACT Artificial propagation and wild release may influence the genetic integrity of wild populations. This practice has been prevalent in fisheries for centuries and is often termed ‘stocking’. In the Laurentian Great Lakes (Great Lakes here‐on), walleye populations faced declines from the 1950s to the 1970s, prompting extensive stocking efforts for restoration. By the mid‐2010s, walleye populations showed signs of recovery, but the genetic legacy of stocking on population structure at the genomic level remains unclear. Using a dataset of 45,600 genome‐aligned SNP loci genotyped in 1075 walleye individuals, we investigated the genetic impacts of over 50 years of stocking across the Great Lakes. Population structure was associated with both natural geographic barriers and stocking from non‐native sources. Admixture between Lake Erie walleye and walleye from the re‐populated Tittabawassee River indicate that stocking may have re‐distributed putatively adaptive alleles around the Great Lakes. Genome scans identified FST outliers and evidence of selective sweeps, indicating local adaptation of spawning populations is likely. Notably, one genomic region showed strong differentiation between Muskegon River and walleye from the Tittabawassee River, which was re‐populated by Muskegon strain walleye, suggesting admixture and selection both impact the observed genetic diversity. Overall, our study underscores how artificial propagation and translocations can significantly alter the evolutionary trajectory of populations. The findings highlight the complex interplay between stocking practices and population genetic diversity, emphasising the need for careful management strategies to preserve the genetic integrity of wild populations amidst conservation efforts. [ABSTRACT FROM AUTHOR]

Presents articles related to molecular ecology. Development and characterization of microsatellite markers in Camellia japonica L.; Discussion of microsatellites in walleye Stizostedion vitreum; Isolation and characterization of microsatellites in albatrosses; Others.

Presents a study of genetic microsatellites in the walleye, Stizostedion vitreum, a sport fish species mainly found in the North American waters. Characterization and development of the microsatellites; Description of the methods of the study; Results, conclusions and discussion.