Vibrational spectroscopy coupled to a multivariate analysis tiered approach for argentinean honey provenance confirmation

In the present work, the provenance discrimination of Argentinian honeys was used as case study to compare the capabilities of three spectroscopic techniques as fast screening platforms for honey authentication purposes. Multifloral honeys were collected among three main honey-producing regions of Argentina over four harvesting seasons. Each sample was fingerprinted by FT-MIR, NIR and FT-Raman spectroscopy. The spectroscopic platforms were compared on the basis of the classification performance achieved under a supervised chemometric approach. Furthermore, low- mid- and high-level data fusion were attempted in order to enhance the classification results. Finally, the best-performing solution underwent to SIMCA modelling with the purpose of reproducing a food authentication scenario. All the developed classification models underwent to a “year-by-year” validation strategy, enabling a sound assessment of their long-term robustness and excluding any issue of model overfitting. Excellent classification scores were achieved by all the technologies and nearly perfect classification was provided by FT-MIR. All the data fusion strategies provided satisfying outcomes, with the mid- and high-level approaches outperforming the low-level data fusion. However, no significant advantage over the FT-MIR alone was obtained. SIMCA modelling of FT-MIR data produced highly sensitive and specific models and an overall prediction ability improvement was achieved when more harvesting seasons were used for the model calibration (86.7% sensitivity and 91.1% specificity). The results obtained in the present work suggested the major potential of FT-MIR for fingerprinting-based honey authentication and demonstrated that accuracy levels that may be commercially useful can be reached. On the other hand, the combination of multiple vibrational spectroscopic fingerprints represents a choice that should be carefully evaluated from a cost/benefit standpoint within the industrial context

Fecundity estimates of the Argentine red shrimp Pleoticus muelleri Bate, 1888 off Patagonia (southern Argentina)

Fecundity o/the Argentine red shrimp Pleoticus muelleri Bate, 1888 was estimated stereologically, and its relationship to carapace length and body weight was analysed. Samples from the spawning grounds located in the southern Gull of San Jorge (Southwest Atlantic, 47° S) collected during the peak and at the end of the spawning season were also compared. Moreover, a sample of large females obtained near the city of Rawson (43° 20' S) was included. Observations of the ovocyte diameter distributions showed the existence of two main generations of ovocytes before spawning (undeveloped and ripe). Potential fecundity, defined as the number of yolked ovocytes, ranged from 72 000 to 1 000 000 ova for females with a carapace length of 25 to 55 mm. The relationships fecundity vs body weight and fecundity vs carapace length estimated for females collected in the Gulf of San Jorge and off Rawson showed a better fit to the power model. Mean relative fecundity was 10 444 ovocytes/g body weight (s = 2 150). Production of eggs was found to decrease significantly by the end of the spawning, season, both in terms of lower individual fecundity and of the increase in atretic processes (20 % o/ ripe ovaries with ova undergoing resorption).En el presente estudio, se estima la fecundidad del langostino argentino Pleoticus muelleri Bate, 1888 y se analiza la relación de esta variable con la talla y el peso de los individuos. Se comparan los valores de fecundidad hallados en el sur del golfo San Jorge (Atlántico sudoccidental, 47° S) durante el periodo de máxima actividad reproductiva (enero) y al final de la temporada de puesta (marzo). Estos resultados se complementan con otras estimaciones de fecundidad realizadas con ejemplares de gran tamaño capturados en las cercanías de la ciudad de Rawson (43° 20' S). El análisis histológico de los ovarios maduros y la distribución de diámetros ovocitarios pusieron en evidencia la existencia de dos generaciones ovocitarias principales en el momento previo al desove (los elementos previtelogenéticos y los vitelados). La fecundidad potencial (número de ovocitos vitelados) varió entre 72 000 Y 1 000 000 para un rango de tallas entre 25 y 55 mm de longitud de caparazón. Las relaciones entre la fecundidad y las variables talla y peso se ajustaron al modelo potencial, tanto para los ejemplares de la zona del golfo San Jorge como para los de Rawson. La fecundidad relativa media para los datos agrupados de estas dos áreas durante el pico de actividad reproductiva fue 10 444 (s = 2 150) ovocitos por gramo de hembra. Se observó una marcada disminución en la producción de huevos de los ejemplares del golfo San Jorge al final de la estación de puesta (marzo). Esta diferencia se vio reflejada en el incremento de las atresias, observándose durante marzo el 20 % de los ovarios, aproximadamente, con reabsorción generalizada de ovocitos.Instituto Español de Oceanografí

Merluccius hubbsi (Teleostei: Merlucciidae): stock identification based on reproductive biology in the south-southeast brazilian region

The Argentine hake, Merluccius hubbsi, a demersal-pelagic species found from Rio de Janeiro, Brazil to the Tierra del Fuego, Argentina, has become an important target of the Brazilian bottom-trawler fleet since 2001. Earlier studies focusing on the species have suggested that more than one stock might occur off the Brazilian coast, in accordance with environmental features. In order to evaluate this hypothesis, fish were collected from four different areas in the Brazilian waters in which the hake is distributed, during the summers and winters of 1996-2001 and 2004, the females being used to analyze and compare spatial-temporal variations in ovarian maturation. Gonad indexes were also applied for the same purpose. Results indicate a north-south spawning gradient occurring as from summer at around 21°S to winter near 34°S, leading to the identification of two distinct stocks: one located between 21°S and 29°S (Southeastern stock) and the other between 29°S and 34°S (Southern stock), this latter shared with Uruguay and Argentina. Brazilian stocks present clear signs of overexploitation, the situation calling for an urgent solution.<br>A merluza Merluccius hubbsi, espécie demerso-pelágica distribuída desde o Rio de Janeiro, Brasil, até a Terra do Fogo, Argentina, tornou-se alvo das frotas de arrasto de fundo da região Sudeste-Sul do Brasil desde 2001. Estudos anteriores sobre a biologia da espécie sugeriram a existência de mais de um estoque em águas brasileiras, relacionados a características ambientais. Para verificar esta hipótese, exemplares oriundos de quatro áreas em águas brasileiras foram coletados durante o verão e o inverno nos períodos 1996-2001 e 2004, sendo as fêmeas utilizadas para analisar variações espaço-temporais na maturação gonadal. Para corroborar estas análises também foram aplicados índices gonadais. Os resultados mostraram a ocorrência de um gradiente norte-sul para a desova, que é mais intenso no verão em 21°S e no inverno em 34°S. Foram identificados dois estoques: um denominado Sudeste, que se distribui entre 21°S-29°S, e outro Sul, entre 29°S-34°S, este último compartilhado com o Uruguai e a Argentina. Os estoques brasileiros apresentam sinais de sobrepesca, situação que merece atenção e medidas apropriadas de gestão