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Pablo Oyarzun

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Papers by Pablo Oyarzun

Research paper thumbnail of Differences in sperm ultrastructure between Mytilus chilensis and Mytilus galloprovincialis (Bivalvia, Mytilidae): could be used as a taxonomic trait

Latin American Journal of Aquatic Research, 2014

Research paper thumbnail of Sperm polymorphism and genetic divergence in the mussel Perumytilus purpuratus

Marine biology, 2012

For the first time in a marine bivalve species, geographic intraspecific variation in sperm morph... more For the first time in a marine bivalve species, geographic intraspecific variation in sperm morphology in the Chilean mussel, Perumytilus purpuratus, is reported. Samples were obtained in December 2010 from the rocky intertidal at three locations: Antofagasta (23844 0 01.08 00 S, 70826 0 26.11 00 W), Valparaíso (32857 0 23.07 00 S, 71833 0 01. 86 00 W), and Valdivia (39°50 0 44.26 00 S, 73°25 0 51.99 00 W). Scanning electron microscopy was used to describe sperm traits, and genetic data were obtained by sequencing a 16S mtDNA 427-bp fragment. The results showed geographic intraspecific variation with two statistically significant patterns of genetically differentiated sperm morphologies. One genetic clade was found for Antofagasta and Valparaíso, displaying a unique sperm morphotype with a short acrosome accounting for 26 % of the head length, and the other from Valdivia, with a larger acrosome occupying 47 % of the head length. These results will lead to new research to distinguish among alternative hypotheses: the presence of cryptic species, incipient speciation, or a polymorphism in sperm traits of P. purpuratus.

Research paper thumbnail of Caracterizacion genetica de hibridos entre las especies Mytilus edulis platensis y Mytilus galloprovincialis (Mytilidae: Bivalvia) en la costa chilena

Latin American Journal of Aquatic Research, 2016

This cost-benefit analysis of three industrial bottom gillnet fisheries that operated in SE/S Bra... more This cost-benefit analysis of three industrial bottom gillnet fisheries that operated in SE/S Brazil during 2009, had a double purpose: to determine the economic and financial performance of the average gillnet vessel in the coastal whitemouth croaker (Micropogonias furnieri), the gulf hake (Urophycis mystacea) and monkfish (Lophius gastrophysus) fisheries and to determine the expected effects of applying fishing gear regulation (MPA/MMA Nº12/2012) on the performance of the whitemouth croaker fishing fleet. Crucial to this cost-benefit analysis was to collect data through interviews to vessel owners on these fishing fleets cost structures and their fishing costs levels. Three economic and financial performance indicators were used to assess the condition of these fishing fleets: Net Present Value (NPV), Internal Rate of Return (IRR) and Profitability Index (PI). Results showed different costs levels between fishing fleets but, similar relative importance of cost components across fleets: with running costs being the highest, followed by vessel and labor costs in order of importance, except in the gulf hake fishing fleet. Results from the economic and financial performance assessment showed that these three fishing fleets were in a fragile economic and financial condition, all having IRRs lower that 20% and PIs of 1.7 or lower, too low for a high risk activity like fisheries. This problem been more acute in the whitemouth croaker fishing fleet with the lowest IRR (12.11%) and PI (1.2). Potential effects of applying the fishing regulation showed marginal improvements in the fragile condition of the whitemouth croaker fishing fleet.

Research paper thumbnail of Producción y comportamiento de larvas de especies puras e híbridas entre Mytilus chilensis y Mytilus galloprovincialis obtenidas en laboratorio

Latin american journal …, 2012

ABSTRACT. Adult specimens of M. galloprovincialis from Concepción Bay and M. chilensis from Yalda... more ABSTRACT. Adult specimens of M. galloprovincialis from Concepción Bay and M. chilensis from Yaldad Bay, Chile, were transferred to the laboratory to produce crosses of" pure" and" hybrid" species in order to evaluate early larval development and growth. These variables ...

Research paper thumbnail of Differences in sperm ultrastructure between Mytilus chilensis and Mytilus galloprovincialis (Bivalvia, Mytilidae): could be used as a taxonomic trait

Latin American Journal of Aquatic Research, 2014

Research paper thumbnail of Sperm polymorphism and genetic divergence in the mussel Perumytilus purpuratus

Marine biology, 2012

For the first time in a marine bivalve species, geographic intraspecific variation in sperm morph... more For the first time in a marine bivalve species, geographic intraspecific variation in sperm morphology in the Chilean mussel, Perumytilus purpuratus, is reported. Samples were obtained in December 2010 from the rocky intertidal at three locations: Antofagasta (23844 0 01.08 00 S, 70826 0 26.11 00 W), Valparaíso (32857 0 23.07 00 S, 71833 0 01. 86 00 W), and Valdivia (39°50 0 44.26 00 S, 73°25 0 51.99 00 W). Scanning electron microscopy was used to describe sperm traits, and genetic data were obtained by sequencing a 16S mtDNA 427-bp fragment. The results showed geographic intraspecific variation with two statistically significant patterns of genetically differentiated sperm morphologies. One genetic clade was found for Antofagasta and Valparaíso, displaying a unique sperm morphotype with a short acrosome accounting for 26 % of the head length, and the other from Valdivia, with a larger acrosome occupying 47 % of the head length. These results will lead to new research to distinguish among alternative hypotheses: the presence of cryptic species, incipient speciation, or a polymorphism in sperm traits of P. purpuratus.

Research paper thumbnail of Caracterizacion genetica de hibridos entre las especies Mytilus edulis platensis y Mytilus galloprovincialis (Mytilidae: Bivalvia) en la costa chilena

Latin American Journal of Aquatic Research, 2016

This cost-benefit analysis of three industrial bottom gillnet fisheries that operated in SE/S Bra... more This cost-benefit analysis of three industrial bottom gillnet fisheries that operated in SE/S Brazil during 2009, had a double purpose: to determine the economic and financial performance of the average gillnet vessel in the coastal whitemouth croaker (Micropogonias furnieri), the gulf hake (Urophycis mystacea) and monkfish (Lophius gastrophysus) fisheries and to determine the expected effects of applying fishing gear regulation (MPA/MMA Nº12/2012) on the performance of the whitemouth croaker fishing fleet. Crucial to this cost-benefit analysis was to collect data through interviews to vessel owners on these fishing fleets cost structures and their fishing costs levels. Three economic and financial performance indicators were used to assess the condition of these fishing fleets: Net Present Value (NPV), Internal Rate of Return (IRR) and Profitability Index (PI). Results showed different costs levels between fishing fleets but, similar relative importance of cost components across fleets: with running costs being the highest, followed by vessel and labor costs in order of importance, except in the gulf hake fishing fleet. Results from the economic and financial performance assessment showed that these three fishing fleets were in a fragile economic and financial condition, all having IRRs lower that 20% and PIs of 1.7 or lower, too low for a high risk activity like fisheries. This problem been more acute in the whitemouth croaker fishing fleet with the lowest IRR (12.11%) and PI (1.2). Potential effects of applying the fishing regulation showed marginal improvements in the fragile condition of the whitemouth croaker fishing fleet.

Research paper thumbnail of Producción y comportamiento de larvas de especies puras e híbridas entre Mytilus chilensis y Mytilus galloprovincialis obtenidas en laboratorio

Latin american journal …, 2012

ABSTRACT. Adult specimens of M. galloprovincialis from Concepción Bay and M. chilensis from Yalda... more ABSTRACT. Adult specimens of M. galloprovincialis from Concepción Bay and M. chilensis from Yaldad Bay, Chile, were transferred to the laboratory to produce crosses of" pure" and" hybrid" species in order to evaluate early larval development and growth. These variables ...

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