Population structure and variance effective size of red snapper (Lutjanus campechanus) in the northern Gulf of Mexico*

We assayed allelic variation at 19 nuclear-encoded microsatellites among 1622 Gulf red snapper (Lutjanus campechanus) sampled from the 1995 and 1997 cohorts at each of three offshore localities in the northern Gulf of Mexico (Gulf). Localities represented western, central, and eastern subregions within the northern Gulf. Number of alleles per microsatellite per sample ranged from four to 23, and gene diversity ranged from 0.170 to 0.917. Tests of conformity to Hardy-Weinberg equilibrium expectations and of genotypic equilibrium between pairs of micro-satellites were generally nonsignificant following Bonferroni correction. Significant genic or genotypic heterogeneity (or both) among samples was detected at four microsatellites and over all microsatellites. Levels of divergence among samples were low (FST ≤0.001). Pairwise exact tests revealed that six of seven “significant” comparisons involved temporal rather than spatial heterogeneity. Contemporaneous or variance effective size (NeV) was estimated from the temporal variance in allele frequencies by using a maximum-likelihood method. Estimates of NeV ranged between 1098 and >75,000 and differed significantly among localities; the NeV estimate for the sample from the northcentral Gulf was >60 times as large as the estimates for the other two localities. The differences in variance effective size could ref lect differences in number of individuals successfully reproducing, differences in patterns and intensity of immigration, or both, and are consistent with the hypothesis, supported by life-history data, that different “demographic stocks” of red snapper are found in the northern Gulf. Estimates of NeV for red snapper in the northern Gulf were at least three orders of magnitude lower than current estimates of census size (N). The ratio of effective to census size (Ne/N) is far below that expected in an ideal population and may reflect high variance in individual reproductive success, high temporal and spatial variance in productivity among subregions or a combination of the two

Population structure, long-term connectivity, and effective size of mutton snapper (Lutjanus analis) in the Caribbean Sea and Florida Keys

Genetic structure and average long-term connectivity and effective size of mutton snapper (Lutjanus analis) sampled from offshore localities in the U.S. Caribbean and the Florida Keys were assessed by using nuclear-encoded microsatellites and a fragment of mitochondrial DNA. No significant differences in allele, genotype (microsatellites), or haplotype (mtDNA) distributions were detected; tests of selective neutrality (mtDNA) were nonsignificant after Bonferroni correction. Heuristic estimates of average long-term rate of migration (proportion of migrant individuals/generation) between geographically adjacent localities varied from 0.0033 to 0.0054, indicating that local subpopulations could respond independently of environmental perturbations. Estimates of average longterm effective population sizes varied from 341 to 1066 and differed significantly among several of the localities. These results indicate that over time larval drift and interregional adult movement may not be sufficient to maintain population sustainability across the region and that there may be different demographic stocks at some of the localities studied. The estimate of long-term effective population size at the locality offshore of St. Croix was below the minimum threshold size considered necessary to maintain the equilibrium between the loss of adaptive genetic variance from genetic drift and its replacement by mutation. Genetic variability in mutton snapper likely is maintained at the intraregional level by aggregate spawning and random mating of local populations. This feature is perhaps ironic in that aggregate spawning also renders mutton snapper especially vulnerable to overexploitation

MOSAIC: A Scalable reconfigurable 2D array system for NDT

This paper documents the development of a scalable 2D array system, or Mosaic that can be targeted at a wide range of NDT applications by way of a reconfigurable tile that can be tessellated to form arrays of any size and shape. Close coupling permits utilization of excitation voltages as low as +/-3.3V with insertion loss of 48dB on reflection from an aluminum back wall at 73mm achieved using 2D arrays without decoding

Population Structure, Long-Term Connectivity, and Effective Size of Mutton Snapper (\u3ci\u3eLutjanus analis\u3c/i\u3e) In the Caribbean Sea and Florida Keys

Genetic structure and average long-term connectivity and effective size of mutton snapper (Lutjanus analis) sampled from offshore localities in the U.S. Caribbean and the Florida Keys were assessed by using nuclear-encoded microsatellites and a fragment of mitochondrial DNA. No significant differences in allele, genotype (microsatellites), or haplotype (mtDNA) distributions were detected; tests of selective neutrality (mtDNA) were nonsignificant after Bonferroni correction. Heuristic estimates of average long-term rate of migration (proportion of migrant individuals/generation) between geographically adjacent localities varied from 0.0033 to 0.0054, indicating that local subpopulations could respond independently of environmental perturbations. Estimates of average long-term effective population sizes varied from 341 to 1066 and differed significantly among several of the localities. These results indicate that over time larval drift and interregional adult movement may not be sufficient to maintain population sustainability across the region and that there may be different demographic stocks at some of the localities studied. The estimate of long-term effective population size at the locality offshore of St. Croix was below the minimum threshold size considered necessary to maintain the equilibrium between the loss of adaptive genetic variance from genetic drift and its replacement by mutation. Genetic variability in mutton snapper likely is maintained at the intraregional level by aggregate spawning and random mating of local populations. This feature is perhaps ironic in that aggregate spawning also renders mutton snapper especially vulnerable to overexploitation

Genetic Studies of Hatchery-Supplemented Populations of Red Drum in Four Texas Bays

Abstract.-Genetic diversity, population structure, average long-term effective population size (N e ), and average long-term genetic migration rate of red drum Sciaenops ocellatus in each of four Texas bays were assessed using variation in 13 nuclear-encoded microsatellites among samples from the 2004 and 2005 cohorts. No significant differences in genetic diversity were detected among bays. Levels of gene diversity of red drum in each bay were equal to or greater than estimates reported for microsatellites in red drum sampled previously from two of the four bays and from other bays in the southeastern USA, including some that had not yet been supplemented with hatchery-raised fish. Tests of the homogeneity of allele and genotype distributions (including analysis of molecular variance) among the four bays were nonsignificant. Estimates of the migration rate (m) between bays ranged from 0.08% to 0.15%, with the average long-term number of migrants (calculated as N e 3 m) between bays estimated to range from 1.04 to 2.37 fish/generation. Estimates of average long-term N e in the four bays ranged from 1,302 to 1,581 fish and collectively were well within the range hypothesized to support sustained, long-term persistence. The estimates of N e also were, on average, five to six times higher than comparable estimates reported for the 1986-1989 red drum cohorts sampled from seven bays across the northern Gulf of Mexico. Adjustment of long-term N e in each of the four bays relative to bay-specific spatial parameters revealed a positive relationship with red drum abundance as measured by catch-per-unit-effort statistics compiled by the Texas Parks and Wildlife Department between 1982 and 2005. The observed high levels of genetic diversity, estimates of average long-term N e , and increased N e over the past 15-20 years are consistent with the hypothesis that the Texas Parks and Wildlife Department's stock enhancement program has not genetically compromised the resident red drum subpopulations in the four bays

Microsatellite multiplex panels for genetic studies of gray snapper (Lutjanus griseus) and lane snapper (Lutjanus synagris)

Microsatellites are codominantly inherited nuclear-DNA markers (Wright and Bentzen, 1994) that are now commonly used to assess both stock structure and the effective population size of exploited fishes (Turner et al., 2002; Chistiakov et al., 2006; Saillant and Gold, 2006). Multiplexing is the combination of polymerase chain reaction (PCR) amplification products from multiple loci into a single lane of an electrophoretic gel (Olsen et al., 1996; Neff et al., 2000) and is accomplished either by coamplification of multiple loci in a single reaction (Chamberlain et al., 1988) or by combination of products from multiple single-locus PCR amplifications (Olsen et al., 1996). The advantage of multiplexing micro-satellites lies in the significant reduction in both personnel time (labor) and consumable supplies generally required for large genotyping projects (Neff et al., 2000; Renshaw et al., 2006)

Projet « cabinets de groupe » : collaboration entre médecine de premier recours et psychiatrie [« Group medical practices » project : collaboration between primary care medicine and institutional public psychiatry]

Collaboration between primary care medicine and psychiatry is a well-known challenge. In order to improve access to psychological care for patients undergoing primary care, the « group medical practices » project proposes a collaborative care model in which a psychiatrist employed by a public psychiatric institution integrates group medical practices in order to provide assistance to primary care physicians. It is thus able to evaluate patients directly in the practices and to offer supervision and consilium spaces to primary care physicians

Genetic effects on tolerance to acute cold stress in red drum, Sciaenops ocellatus L

Abstract Genetic e¡ects on cold-stress tolerance were assessed for red drum (Sciaenops ocellatus), an economically important sciaenid ¢sh in the southern USA. Thirty¢ve families were generated via 'natural'spawning of multiple sets of ¢ve breeders (three dams  two sires) in individual brood tanks. O¡spring from the 35 families were transferred abruptly from an acclimation temperature of $24 1C to 5.7 1C and maintained subsequently at an average temperature of 6.5 1C. O¡spring were assigned a posteriori to individual brood¢sh (dam and sire) based on genotypes at nuclear-encoded microsatellites. Heritability of the survival^time probability function was estimated using a proportional hazard approach and an animaladditive model. The estimated heritability was 0.20 (95% CI: 0.07^0.40), indicating a signi¢cant genetic component to acute cold-stress tolerance in red drum

Microsatellite Markers for Red Drum, Sciaenops ocellatus

Polymerase chain reaction (PCR) primers are reported for 68 nuclear-encoded microsatellites developed during the past several years from genomic libraries of red drum (Sciaenops ocelwtus). All68 microsatellites were tested for reproducibility and polymorphism on a sample of five to 12 red drum; 60 of the microsatellites were found to be polymorphic. Estimates of observed and expected heterozygos- ity (gene diversity) and tests of conformity of genotypes to Hardy-Weinberg equi- librium were carried out for a subset of 31 microsatellites on a larger sample of 45 adults provided by Texas Parks and Wildlife. Levels of allelic and gene diversity were average relative to values observed for marine and anadromous fishes. The set of genetic markers should be useful for a variety of studies, including moni- toring and assessment of red drum stock enhancement