Population aggregation analysis of three caviar-producing species of sturgeons and implications for the species identification of black caviar.

Abstract: We describe a reliable method for the identification of the species source for caviar. The assay is based on the identification of diagnostic nucleotide positions in the mitochondrial Análisis de Agregación de Poblaciones de Tres Especies de Esturiones Productoras de Caviar y sus Implicaciones en la Identificación de Especies de Caviar Negro Resumen: Describimos un método confiable para la identificación de las especies fuente de caviar. La prueba se basa en la identificación de posiciones diagnóstico de nucleótidos en el gen citocromo b de una base de datos de secuencias de 20 de las 25 especies de esturiones vivientes. La colección de datos se basa en PCR y puede identificar fácilmente los estados de diversas posiciones diagnóstico de nucleótidos del gen citocromo b de las tres especies comerciales de esturiones mas importantes productoras de caviar

Research Tools to Investigate Movements, Migrations, and Life History of Sturgeons (Acipenseridae), with an Emphasis on Marine-Oriented Populations

Worldwide, sturgeons (Acipenseridae) are among the most endangered fishes due to habitat degradation, overfishing, and inherent life history characteristics (long life span, late maturation, and infrequent spawning). As most sturgeons are anadromous, a considerable portion of their life history occurs in estuarine and marine environments where they may encounter unique threats (e.g., interception in non-target fisheries). Of the 16 marine-oriented species, 12 are designated as Critically Endangered by the IUCN, and these include species commercially harvested. We review important research tools and techniques (tagging, electronic tagging, genetics, microchemistry, observatory) and discuss the comparative utility of these techniques to investigate movements, migrations, and life-history characteristics of sturgeons. Examples are provided regarding what the applications have revealed regarding movement and migration and how this information can be used for conservation and management. Through studies that include Gulf (Acipenser oxyrinchus desotoi) and Green Sturgeon (A. medirostris), we illustrate what is known about well-studied species and then explore lesser-studied species. A more complete picture of migration is available for North American sturgeon species, while European and Asian species, which are among the most endangered sturgeons, are less understood. We put forth recommendations that encourage the support of stewardship initiatives to build awareness and provide key information for population assessment and monitoring

Research Tools to Investigate Movements, Migrations, and Life History of Sturgeons (Acipenseridae), with an Emphasis on Marine-Oriented Populations

Worldwide, sturgeons (Acipenseridae) are among the most endangered fishes due to habitat degradation, overfishing, and inherent life history characteristics (long life span, late maturation, and infrequent spawning). As most sturgeons are anadromous, a considerable portion of their life history occurs in estuarine and marine environments where they may encounter unique threats (e.g., interception in non-target fisheries). Of the 16 marine-oriented species, 12 are designated as Critically Endangered by the IUCN, and these include species commercially harvested. We review important research tools and techniques (tagging, electronic tagging, genetics, microchemistry, observatory) and discuss the comparative utility of these techniques to investigate movements, migrations, and life-history characteristics of sturgeons. Examples are provided regarding what the applications have revealed regarding movement and migration and how this information can be used for conservation and management. Through studies that include Gulf (Acipenser oxyrinchus desotoi) and Green Sturgeon (A. medirostris), we illustrate what is known about well-studied species and then explore lesser-studied species. A more complete picture of migration is available for North American sturgeon species, while European and Asian species, which are among the most endangered sturgeons, are less understood. We put forth recommendations that encourage the support of stewardship initiatives to build awareness and provide key information for population assessment and monitoring

Population structure, connectivity, and demographic history of an apex marine predator, the bull shark <i>Carcharhinus leucas</i>

Knowledge of population structure, connectivity, and effective population size remains limited for many marine apex predators, including the bull shark Carcharhinus leucas. This large‐bodied coastal shark is distributed worldwide in warm temperate and tropical waters, and uses estuaries and rivers as nurseries. As an apex predator, the bull shark likely plays a vital ecological role within marine food webs, but is at risk due to inshore habitat degradation and various fishing pressures. We investigated the bull shark\u27s global population structure and demographic history by analyzing the genetic diversity of 370 individuals from 11 different locations using 25 microsatellite loci and three mitochondrial genes (CR, nd4, and cytb). Both types of markers revealed clustering between sharks from the Western Atlantic and those from the Western Pacific and the Western Indian Ocean, with no contemporary gene flow. Microsatellite data suggested low differentiation between the Western Indian Ocean and the Western Pacific, but substantial differentiation was found using mitochondrial DNA. Integrating information from both types of markers and using Bayesian computation with a random forest procedure (ABC‐RF), this discordance was found to be due to a complete lack of contemporary gene flow. High genetic connectivity was found both within the Western Indian Ocean and within the Western Pacific. In conclusion, these results suggest important structuring of bull shark populations globally with important gene flow occurring along coastlines, highlighting the need for management and conservation plans on regional scales rather than oceanic basin scale

The Informativeness of Micro and Macro Information During Economic Crisis and Non-crisis Periods

We investigate whether the informativeness of reported profitability and macroeconomic expectations differs between non-crisis and crisis economic periods by analyzing data for five European Union countries over the period 2005-2011. We find, first, macroeconomic expectations: a) are useful in predicting future profitability only in non-crisis periods, and b) are not useful in predicting stock returns in either period. Second, reported profitability: a) is useful in predicting future profitability in both crisis and non-crisis periods but less so in crisis periods, and b) is useful in predicting returns only in crisis periods. The cash flow component of profitability drives these results while the accrual component appears to be uninformative. Third, expected profitability, implied by the interaction between current profitability and macroeconomic expectations, is informative in predicting future profitability in both crisis and non-crisis periods and is efficiently priced only for high profitability firms during non-crisis periods

Population aggregation analysis of three caviar-producing species of sturgeons and implications for the species identification of black caviar.

Abstract: We describe a reliable method for the identification of the species source for caviar. The assay is based on the identification of diagnostic nucleotide positions in the mitochondrial Análisis de Agregación de Poblaciones de Tres Especies de Esturiones Productoras de Caviar y sus Implicaciones en la Identificación de Especies de Caviar Negro Resumen: Describimos un método confiable para la identificación de las especies fuente de caviar. La prueba se basa en la identificación de posiciones diagnóstico de nucleótidos en el gen citocromo b de una base de datos de secuencias de 20 de las 25 especies de esturiones vivientes. La colección de datos se basa en PCR y puede identificar fácilmente los estados de diversas posiciones diagnóstico de nucleótidos del gen citocromo b de las tres especies comerciales de esturiones mas importantes productoras de caviar

Diversity and Movement of Reef-Associated Elasmobranchs at a Caribbean Oceanic Atoll (Glover\u27s Reef, Belize): Implications for Marine Reserve Design

Little is known about the sharks and rays of the Mesoamerican Caribbean. Studies of the elasmobranch fauna of Glover’s Reef Marine Reserve (GRMR), Belize, demonstrate its importance for a diversity of elasmobranchs and provide essential information for marine protected area design. A five year survey documents GRMR as a nursery area for four species of elasmobranchs and the use of the atoll by eight other species (6 sharks, 2 batoids), including the Galapagos shark, C. galapagensis, previously known in the Caribbean from only one specimen. Differences exist in elasmobranch abundance, species composition and intraspecific size distribution among shallow lagoon, deep lagoon, ocean reef, and inshore habitats. Telemetry studies of two common sharks illustrate movement within and outside of the atoll and across the boundaries of the no-take zone of the marine reserve. GRMR is an important breeding ground for several species of elasmobranchs and in need of further study and conservation. For effective conservation of elasmobranchs, an ecosystem based approach should be taken in designing marine protected areas. Zoned management plans are needed that incorporate a fairly large no-take reserve that protects diverse habitats and the connections between them, surrounded by a larger area where fishing is regulated