Examinando por Autor "Navarro, Jorge M."
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Ítem Distribución vertical de la macroinfauna asociada a bivalvos en una planicie intermareal sedimentaria del sur de Chile(Universidad de Valparaíso. Facultad de Ciencias del Mar, 2012-12) Acuña, Karin; Duarte, Cristian; Jaramillo, Eduardo; Contreras, Heraldo; Manzano, Mario; Navarro, Jorge M.La estructura comunitaria de la macroinfauna que habita en planicies intermareales, así como su distribución en la columna de sedimento, puede ser influida por una combinación de factores físicos y biológicos. El objetivo de este estudio fue determinar y comparar la distribución vertical y estructura comunitaria de la macroinfauna asociada a sedimentos con navajuelas (Tagelus dombeii) en la planicie intermareal de Pelluco, sur de Chile, durante febrero y septiembre de 2004. Se recolectaron muestras de sedimento y macroinfauna en sitios con y sin bivalvos, con un cilindro plástico dividido en 5 partes iguales. Durante ambos meses de muestreo, el número de especies, abundancia y biomasa total de la macroinfauna alcanzó, en casi todas las láminas sedimentarias, valores más altos en el sitio con T. dombeii. En ambos meses de muestreo, la composición faunística fue significativamente distinta entre sitios con y sin T. dombeii. Además, la similitud en la composición faunística entre láminas sedimentarias fue mayor en el sitio con T. dombeii durante ambos meses de muestreo. Estos resultados sugieren que el proceso de bioperturbación de T. dombeii afecta la distribución vertical de la fauna asociada y que este efecto no sería dependiente de la época del año.Ítem Genetic structure and diversity of the Chilean flat oyster Ostrea chilensis (Bivalvia: Ostreidae) along its natural distribution from natural beds subject to different fishing histories(Brazilian Journal of Genetics, 2022) Toro, Jorge E.; Oyarzún, Pablo A.; Toledo, Felipe E.; Navarro, Jorge M.; Illesca, Alex F.; Gardner, Jonathan P.A.Ostrea chilensis (Küster, 1844), the flat oyster, is native to Chile and New Zealand. In Chile, it occurs in a few natural beds, from the northern part of Chiloé Island (41 ºS) to the Guaitecas Archipelago (45 ºS). This bivalve is slow growing, broods its young, and has very limited dispersal potential. The Ostrea chilensis fishery has been over-exploited for a number of decades such that in some locations oysters no longer exist. The aim of this study was to study the genetic diversity of the Chilean flat oyster along its natural distribution to quantify the possible impact of the dredge fishery on wild populations. The genetic structure and diversity of Ostrea chilensis from six natural beds with different histories of fishing activity were estimated. Based on mitochondrial (Cytb) and nuclear (ITS1) DNA sequence variation, our results provide evidence that genetic diversity is different among populations with recent history of wild dredge fishery efforts. We discuss the possible causes of these results. Ultimately, such new information may be used to develop and apply new management measures to promote the sustainable use of this valuable marine resource. © Sociedade Brasileira de Genética.Ítem Proximal and fatty acid analysis in Ostrea chilensis, Crassostrea gigas and Mytilus chilensis (Bivalvia: Mollusca) from southern Chile(Public Library of Science, 2022-07) Valenzuela, Andrea; Oyarzún, Pablo A.; Toro, Jorge E.; Navarro, Jorge M.; Ramírez, Oscar; Farias, AnaOysters and blue mussels are important hydrobiological resources for aquaculture. In Chile, they are farming on the Chiloé island, where around 18% of the world’s mussels are produced, however, their nutritional dynamics are largely unknown. For this reason, the objective of this study was to determine the proximal biochemical composition and the fatty acid profile in the Chilean oyster (Ostrea chilensis), the Pacific oyster (Crassostrea gigas) and the Chilean mussel (Mytilus chilensis), to perform an intra and interspecific comparison. Shellfish sampled in winter were characterized by a high protein content, followed by medium values for lipid content and a low carbohydrate content compared to similar species in Europe. Also, oysters and mussels were found to be rich in omega-3 long chain polyunsaturated fatty acid (n-3 LC-PUFA), so they can be considered excellent functional food option for a healthy human diet. Their high contribution of n-3 LC-PUFA ranged between 5.2–12.9 μg FA mg-1 dry weight with high n-3/n-6 ratios, which depends on both the species and the on-growing location. Both taxa can be considered a plausible option to promote a healthy diet of marine origin in future generations. Also, these results could benefit the projection and development of aquaculture of these mollusks. © 2022 Valenzuela et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.Ítem Settlement of Chilean Flat Oysters (Ostrea chilensis) on Ribbed Mussel Shell Collectors for Commercial Grow-Out: Towards Sustainable Management(Multidisciplinary Digital Publishing Institute (MDPI), 2024) Oyarzún, Pablo A.; Hidalgo-Cabrera, Almendra; Stam, Gerrit; Estrada, Juan Manuel; Ruiz-Tagle, Gonzalo; Navarro, Jorge M.; Toro, Jorge E.Ostrea chilensis (a flat oyster) is native to Chile and New Zealand. In Chile, this oyster has been cultured and harvested for at least 80 years. However, the culture of flat oysters has not developed like other aquaculture activities in Chile, mainly due to the inefficiency of the collectors (made of ribbed mussel shells) and the lack of spats produced. The objective of this study was to determine the capacity of spat collectors for the settlement of O. chilensis. For this purpose, field and laboratory experiments were carried out. Our results indicated that oyster larvae do not have a preference for either side of the shell (periostracum or nacreous) to settle on. However, after one year of growth in the field, juveniles were more abundant on the nacreous side of the shell (spat collector). Also, the oysters that settled on the nacreous side of the valve were larger. This was due to the fact that the periostracum had a greater number of epibionts, and they competed for space and resources with the settled oyster spats, causing a decrease in the abundance of oyster spats on that surface. Our findings raise the possibility that collectors could improve efficiency in the production of spats. Finally, we discuss the implications of these results for the Chilean oyster-farming industry.