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Objective: The Yaqui Catfish Ictalurus pricei, a species that is endemic to the southwestern United States and west‐central Chihuahua and Sonora, Mexico, is extinct in the United States and extremely endangered in Mexico due to habitat loss and hybridization with nonnative Channel Catfish I. punctatus. To re‐establish populations in the United States, a binational program consisting of broodstock collection, fish propagation, stocking, and poststocking monitoring is necessary. This programmatic approach is encapsulated within a Conservation Propagation and Stocking Program (CPSP), which documents important recovery actions, such as genetic management, fish culture, stocking, and poststocking assessments. The focus of our work is to identify the optimal stocking strategy for Yaqui Catfish, thereby informing the framework of a CPSP for the species' recovery. Methods: Our strategy involved simulating population growth using an age‐structured simulation model with varying stocking contribution rates, stocking densities, and stocking frequencies and incorporating these biological data with economic information within a utility function to quantify stocking costs. Result: The optimal strategy requires releasing Yaqui Catfish at a density of 200 fish/ha every 5 years. This strategy excludes natural recruitment because historically, stocked Yaqui Catfish inhabited waters that were either too small or devoid of habitat to induce natural spawning. However, if larger waters or waters having appropriate habitats (e.g., interstitial spaces) are also stocked, it should increase natural recruitment, thereby (1) enabling populations to become self‐sustaining and (2) drastically reducing the reliance on hatcheries for stocking and salvage of declining populations. Conclusion: Our results provide important stocking recommendations within a CPSP, emphasizing the need to build a broodstock before genetically pure Yaqui Catfish disappear. The successful implementation of the optimal stocking strategy requires multiple locations for stocking fish and is contingent on strengthening binational partnerships. This approach fills an important void in Yaqui Catfish reestablishment, helping to prime the successful recovery of this species. Impact statementThe Yaqui Catfish, once native to regions of the United States and Mexico, faces near extinction due to habitat degradation and nonnative hybridization. A binational Conservation Propagation and Stocking Program offers a promising solution, suggesting for the release of 200 fish per hectare every 5 years in the United States. The initiatives success, however, hinges on using multiple stocking locations in Mexico and bolstering binational collaboration. [ABSTRACT FROM AUTHOR]

We investigated the environmental life history of widely distributed threatened and endangered sturgeons in large rivers of the central United States that experience different regulatory regimes and management priorities. Using microchemistry techniques, our goal was to assess how to improve species conservation by dampening the incongruity that often occurs between management and species' ecological requirements, particularly at large spatial scales. Pallid sturgeon (Scaphirhynchus albus), shovelnose sturgeon (Scaphirhynchus platorynchus), and their hybrids were analyzed for [sup.88]Sr and [sup.44]Ca and related to a geographically relevant range of Sr:Ca values for the Missouri and Mississippi rivers to quantify large-scale environmental history. We found natal origin of 81% of all wild sturgeon collected was the lower Missouri River. Pallid and hybrid sturgeon used the middle and upper Mississippi rivers more frequently as they aged, whereas shovelnose sturgeon occupied the lower Missouri River more often throughout life. Our results highlight a mismatch between conservation boundaries and sturgeon river use. Managers should consider expanding current protections for pallid sturgeon to include the unprotected sections of the Mississippi River and that research and conservation actions consider the importance of Mississippi River habitats to Scaphirhynchus sturgeon throughout their life history. Our findings have implications for conserving wide-ranging riverine species at large spatial scales using the framework described here. Nous avons examine le cycle biologique environnemental d'esturgeons a vaste repartition menaces et en peril dans de grandes rivieres du centre des Etats-Unis visees par des regimes de reglementation et des priorites d'amenagement varies. L'objectif consistait a evaluer, a l'aide de methodes microchimiques, comment ameliorer la conservation des especes en attenuant l'incongruite souvent observee entre l'amenagement et les exigences ecologiques des especes, particulierement a grande echelle spatiale. Des esturgeons blancs (Scaphirhynchus albus), des esturgeons a museau plat (Scaphirhynchus platorynchus) et des hybrides des deux ont ete analyses pour le [sup.88]Sr et le [sup.44]Ca et relies a une fourchette de valeurs de Sr:Ca pertinente, geographiquement parlant, pour la riviere Missouri et le fleuve Mississippi, afin de quantifier leur historique environnemental a grande echelle. Nous avons determine que l'origine natale de 81 % de tous les esturgeons sauvages preleves etait le cours inferieur de la riviere Missouri. Les esturgeons blancs et hybrides utilisaient les cours intermediaire et superieur du Mississippi plus frequemment en vieillissant, alors que les esturgeons a museau plat occupaient la basse riviere Missouri plus souvent durant toute leur vie. Nos resultats soulignent une discordance entre les limites des zones de conservation et les cours des rivieres utilises par les esturgeons. Les amenageurs devraient songer a elargir les zones de protection actuelles pour l'esturgeon blanc aux troncons non proteges du Mississippi, et la recherche et les mesures de conservation devraient tenir compte de l'importance des habitats du fleuve Mississippi pour les esturgeons Scaphirhynchus durant tout leur cycle biologique. Nos constatations sont importantes en ce qui concerne la conservation a grande echelle spatiale et utilisant le cadre decrit dans la presente etude d'especes fluviales a vaste repartition. [Traduit par la Redaction], Introduction Movement plays a major role in determining the structure and dynamics of animal populations (Dingle 2014; Nathan et al. 2008; Swingland and Greenwood 1983). The timing and magnitude of [...]

In mammal populations, the spatial and genetic structure can be affected by dispersal, philopatry, and relatedness. Bobcats (Lynx rufus (Schreber, 1777)) are thought to exhibit typical mammalian dispersal behaviour where males disperse and females are philopatric, potentially leading to higher relatedness among females compared with males. We used 10 microsatellite loci to examine population structure and sex-biased dispersal in 146 bobcats sampled in southern Illinois during 1993-2001 using population genetic descriptive statistics, a Bayesian clustering algorithm, relatedness ([r.sub.xy]), and autocorrelation analyses. A randomization test demonstrated that female dyads had significantly higher [r.sub.xy] values with respect to randomly selected dyads ([r.sub.xy] = 0.093 ± 0.222, P = 0.012) and spatial autocorrelation analyses determined that females in close proximity ( Dans les populations de mammiferes, les structures spatiales et geneetiques peuvent etre affecteees par la dispersion, la philopatrie et la consanguinite. On pense que les lynx roux (Lynx rufus (Schreber, 1777)) possedent un comportement de dispersion typique des mammiferes dans lequel les males se dispersent et les femelles sont philopatriques, ce qui entraine potentiellement une plus forte parente entre les femelles qu'entre les males. Nous analysons 10 locus microsatellites afin d'eetudier la structure de population et la dispersion variable en fonction du sexe chez 146 lynx roux eechantillonnees dans le sud de l'Illinois en 1993-2001; nous utilisons des statistiques geenetiques descriptives, un algorithme bayesien de groupement et des analyses de parente; ([r.sub.xy]) et d'autocorrelation. Un test de randomisation montre que les dyades femelles ont des valeurs significativement plus elevees de [r.sub.xy] par rapport aux dyades choisies au hasard ([r.sub.xy] = 0,093 ± 0,222, P = 0,012) et les analyses d'autocorrelation spatiale montrent que les femelles rapprochees ( [Traduit par la Redaction], Introduction The spatial and genetic structures of mammalian populations are shaped considerably by behavioural factors such as dispersal and philopatry. Most mammals exhibit male-biased dispersal and female philopatry (Greenwood 1980) [...]

Muskellunge, Esox masquinongy, is an important recreational freshwater fish native to North America. Since muskellunge populations are often maintained through stocking efforts, advances in muskellunge reproductive technologies are of direct relevance to fishery enhancement. We evaluated the efficiency of inbreeding through induced meiotic diploid gynogenesis. Eggs from six female muskellunge were manually stripped and activated using ultra violet-irradiated yellow perch, Perca flavescens, sperm. Hydrostatic pressure shocking regimes (48 263 kPa) were then applied to the eggs to prevent second polar body expulsion producing unambiguous meiotic gynogens. Six female dams and samples of 12-20 of their gynogenetic progeny were genotyped at seven polymorphic microsatellite loci. Chromosomal recombination frequencies of microsatellite loci based on retention of heterozygosity among gynogens ranged from 0.043 to 0.839 (0.576 ± 0.237). There were no statistical differences in recombination frequency among females at any of the loci. The average inbreeding coefficient ( F-value) ranged from 0.581 to 0.979, equivalent to three to fourteen generations of full-sibling crosses respectively. The average F-value overall was 0.712, equivalent to between five and six generations of full-sibling crosses. Centromere map distances of the seven microsatellite loci ranged from 2.15 to 41.95 cM and meiotic gynogenesis was useful in eliminating heterozygosity at loci proximal to the centromere, but not distal. Since the age at maturity of female muskellunge is approximately 5 years, gynogenesis may pose an expeditious alternative to traditional breeding strategies for creation of homozygous pedigrees for some loci that may be outcrossed to introduce positive heterozygosity effects in the offspring. [ABSTRACT FROM AUTHOR]

The article focuses on a research conducted in order to investigate genetic diversity and spatial genetic differentiation in a cyclical forest pest, the southern pine beetle, Dendroctonus frontalis throughout thesoutheastern U.S. It discusses the use of microsatellite variation for comparing the southern pine beetle's pattern of population structure to phylogeographic patterns and providing information about dispersal.

The southern pine beetle, Dendroctonus frontalis Zimmerman, is the most destructive insect pest of pine forests in the southeastern United States, Mexico, and Central America. Southern pine beetle aggressively attacks pine trees, and when in epidemic stages, they are capable of killing even the most healthy pine trees in a short period of time. Despite the amount of destruction caused by the southern pine beetle and the amount of monetary loss faced by the timber industry and recreation, the population genetics of this species has been limited to comparisons among distant geographic locations. This study investigates the fine-scale genetic population structure of the southern pine beetle in Mississippi. Very little genetic differentiation was observed among samples. Bayesian assignment testing failed to detect multiple groups within all samples; estimates of genetic differentiation and genetic distance were very low in magnitude; and a Mantel test did not reveal a significant relationship between genetic distance and geographic distance. These results suggest that management of the southern pine beetle needs to consider the potential movements of individuals within and among national forests and should be focused on a large scale, at least as big as continuously forested areas and possibly even multiple forests. These results further suggest that removal of beetle-infested trees is important. [ABSTRACT FROM AUTHOR]