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Cutting-edge DNA methylation-based epigenetic aging techniques were applied to Gulf of Mexico northern red snapper (Lutjanus campechanus; n = 10; 1-26 years old) and red grouper (Epinephelus morio; n = 10; 2-14 years old). Bisulfiteconverted restriction site-associated DNA sequencing was used to identify CpG sites (cytosines followed by guanines) that exhibit age-correlated DNA methylation, and species-specific epigenetic clocks developed from hundreds of CpG sites in each species showed strong agreement between predicted and otolith-derived age [r.sup.2] > 0.99 for both species). Results suggest epigenetic age estimation could provide an accurate and efficient approach to mass-aging fishes in a non-invasive manner. Des methodes epigenetiques de pointe de determination de l'age reposant sur la methylation de l'ADN ont ete appliquees au vivaneau campeche (Lutjanus campechanus; n = 10; 1-26 ans) et au merou rouge (Epinephelus morio; n = 10; 2-14 ans). Le sequencage avec conversion au bisulfite d'ADN associe a des sites de restriction a ete utilise pour cerner des sites CpG (cytosines suivies de guanines) qui presentent une methylation de l'ADN correlee a l'age, et des horloges epigenetiques propres a l'espece developpees a partir de centaines de sites CpG de chaque espece ont revele de fortes concordances entre les ages predits et les ages obtenus par analyse d'otolites [r.sup.2] > 0,99 pour les deux especes). Les resultats donnent a penser que l'estimation epigenetique de l'age pourrait constituer une approche non invasive exacte et efficiente de determination des ages de quantites massives de poissons., Introduction Age data are fundamental to determining life history parameters (e.g., age-at-length, age-at-maturity, age-related fecundity) and are thus critical for fisheries assessment and management, particularly when age-structured stock assessment models [...]

Texas Parks and Wildlife Department restricts movement of eastern oysters Crassostrea virginica among Texas bay systems because of potential disease transfer and genetic differences in natural oyster stocks. Oyster diseases, such as bonamiosis, which was found serendipitously in 2007 in Florida waters, and MSX (Haplosporidium nelsoni) have not been characterized in Texas bays. Therefore, it is prudent to periodically examine C. virginica and other bivalve species (e.g., Ostrea cqueslris and hognomon sp.) from Texas bays for the presence of the causative agents of these diseases, that is, Bonamia spp. and H. nelsoni, as well as known diseases such as dermo (Perkinsus marinus). Eastern oysters (n = 30/bay) were collected from October to December 2016 from five Texas bays and analyzed for the presence of these parasites. In addition, 89 historical oyster tissue samples collected from two Texas bays in 2010 and 2011 and 37 flat tree oysters Isognomon alatus collected from a single Texas bay in December 2017 were examined. All specimens collected in 2016/2017 were assessed by PCR and histology for the presence of Bonamia spp., H. nelsoni, and P. marinus, whereas 2010/2011 samples were only assessed by PCR. Neither Bonamia spp. nor H. nelsoni were detected in any collected samples. Although 15% of the 2016 eastern oyster samples and 29% of the 2010 to 2011 eastern oyster samples contained P. marinus, the parasite was not found in any fiat tree oyster. Sanger sequencing of isolated DNA was performed on samples that were positive for dermo as well as the positive controls for Bonamia sp. and H. nelsoni, which confirmed results. These results serve as a point reference that indicate Bonamia spp. and H. nelsoni are not currently present in Texas bays, but continued biennial monitoring is suggested. KEY WORDS: Bonamia, MSX, Haplosporidium, dermo, Perkinsus, Texas, oyster, INTRODUCTION The eastern oyster Crassostrea virginica has increasingly been negatively affected by natural and human-induced stressors throughout its range (Grabowski et al. 2017, Keithly & Roberts 2017), resulting in an [...]

Red snapper, Lutjanus campechanus , supports one of the more important fisheries in marine waters of the United States. Consequently, it has been the focus of intensive fisheries research for more than 20 years. Here, we present a genomic analysis of population structure that uses a landscape genetics approach to characterize patterns of variation in adult red snapper in the Gulf of Mexico (GOM) alongside a synoptic view of decades of stock-structure research. The results support Atlantic and GOM stocks and indicate weak heterogeneity within the GOM. Furthermore, redundancy analysis using Moran Eigenvector Maps based on physical distance, larval dispersal probability, and adult dispersal probability reveal heterogeneity on various spatial scales, with adult movement explaining a larger component of variation than spatial position or larval dispersal. Results of this study support the idea that red snapper in the GOM display metapopulation structure, but also suggest a potential genetic discontinuity along the West Florida Shelf not previously described. The approach of using landscape genomics and dispersal data (larval and/or adult) to better understand metapopulation dynamics is promising for not only red snapper, but also for other marine species that occupy a diversity of habitats and are seemingly distributed continuously. [ABSTRACT FROM AUTHOR]