Characterization of mono-sex Nile tilapia (Oreochromis niloticus) hatcheries in Bangladesh

survey was conducted of the mono-sex tilapia hatcheries in Bangladesh to analyze the structure and management of the hatchery sector in Bangladesh. Eighty-five hatcheries were surveyed by a questionnaire designed to obtain information on owner details, staffing, hatchery production capacity, management processes, and performance for the year 2009, and data from farms supplied by each hatchery. Thirteen quantitative variables were used for a principal component analysis (PCA). Four principal components had eigenvalues greater than 1, collectively expressing 77.0% of the total variance with the first two components, (50.8% of total variance) reflecting the volume of fry production and available facilities. Multiple correspondence analysis (MCA) was used to include qualitative variables related to hatchery management and educational level of the owners in the analysis. A two-step cluster analysis using the results of PCA and MCA identified two different groups of hatcheries. One cluster was characterized by high capacity of production of fry, infrastructure and manpower. The other cluster had moderate scales of production. In summary, the management of hatcheries was very similar across Bangladesh with the main difference between them being scale of fry productio

Detection of hybridization between Chinese carp species (Hypophthalmichthys molitrix and Aristichthys nobilis) in hatchery broodstock in Bangladesh, using DNA microsatellite loci

Hybridization between silver carp (Hypophthalmichthys molitrix) and bighead carp (Aristichthys nobilis) has been reported to occur fairly frequently in commercial aquaculture hatcheries in Bangladesh. The consequences of hybridization for broodstock purity had not previously been investigated. Allelic variation at three microsatellite DNA loci isolated from silver carp routinely distinguished between silver carp and bighead carp. These markers were used in the analysis of samples collected from hatcheries in different regions of Bangladesh. Of 422 hatchery broodstock that were morphologically identified as silver carp, 8.3% had bighead allele(s) at one or more of the three microsatellite loci, while 23.3% of the 236 fish morphologically identified as bighead carp had silver carp allele(s) at one or more loci. The results suggested that while some of these fish might be F1 hybrids, others had more complex genotypes, suggesting further generations of hybridization or introgression between the species in hatcheries, with potentially damaging consequences for the integrity of these stocks and their performance in aquaculture

Data from an international multi-centre study of statistics and mathematics anxieties and related variables in university students (the SMARVUS dataset)

This large, international dataset contains survey responses from N = 12,570 students from 100 universities in 35 countries, collected in 21 languages. We measured anxieties (statistics, mathematics, test, trait, social interaction, performance, creativity, intolerance of uncertainty, and fear of negative evaluation), self-efficacy, persistence, and the cognitive reflection test, and collected demographics, previous mathematics grades, self-reported and official statistics grades, and statistics module details. Data reuse potential is broad, including testing links between anxieties and statistics/mathematics education factors, and examining instruments’ psychometric properties across different languages and contexts. Data and metadata are stored on the Open Science Framework website [https://osf.io/mhg94/]