Composição e diversidade da ictiofauna do reservatório La Viña (Córdoba, Argentina)

Several dams have been built in central and north Argentina. There are more than 20 reservoirs in Córdoba province, with a total estimated surface area of around 15,000 ha. Although construction of dams continues, some aspects about the richness, abundance and diversity of ichthyofauna in many of these environments are unknown, which prevents adequate management of fish resources. The goal of this work was to evaluate specific richness and diversity of ichthyofauna in La Viña reservoir (31° 47' S and 65° 01' W, 1,050 ha, 846 m asl), one of the major reservoirs in Córdoba. Fifteen seasonal samplings were made in 1999-2002 using trawl nets and gillnets. A total of 3,242 specimens belonging to 7 species distributed in 5 orders and 5 families were caught. The tetra Astyanax eigenmanniorum (52.9%) and the silverside Odontesthes bonariensis (29.3%) were the most abundant species; the latter is the main target species for lake fishing and had greatest biomass (63.8%). Average diversity for all samples was H'T=1.63 (95% confidence interval 1.49 to 1.77). Shannon-Wiener and Simpson diversity indexes values were generally intermediate. Specific richness of La Viña reservoir was moderate compared with other impoundments in central and north Argentina.Na área central e norte da Argentina há uma importante quantidade de represas. Na província de Córdoba, existem, na atualidade, mais de 20 reservatórios que ocupam uma superfície aproximada de 15.000 ha. Embora a construção de represas continue em uma grande quantidade de ambientes, não se conhecem alguns aspectos da riqueza, abundância e diversidade da ictiofauna, dificultando a gestão e manejo dos recursos pesqueiros. O objetivo do trabalho foi avaliar a riqueza específica e a diversidade da ictiofauna do reservatório La Viña (31° 47’ S e 65° 01’ W, 1.050 ha, 846 msnm), um dos mais importantes de Córdoba. No período entre 1999-2002, realizaram-se 15 amostragens estacionais, utilizando-se redes de arrasto e de espera. Coletaram-se 3.242 indivíduos de 7 espécies distribuídas em 5 ordens e 5 famílias. Em função do número total de espécies, as de maior abundância foram lambari Astyanax eigenmanniorum (52,9%) e peixe-rei Odontesthes bonariensis (29,3%), sendo esta última espécie o objetivo da pescaria do lago e a que alcançou a maior biomassa (63,8%). Considerando o total da amostragem, a diversidade média foi de H’T = 1,63, com um intervalo de confiança (95%) de 1,49 a 1,77. No geral, os índices de diversidade de Shannon-Wiener e Simpson foram médios. Comparando com outros reservatórios da área central e norte da Argentina, a riqueza específica do reservatório La Viña é moderada.Facultad de Ciencias Naturales y Muse

Patrones de riesgo e implicancias de la presencia de <i>Contracaecum</i> sp. (Nematoda, anisakidae) en pejerrey <i>Odontesthes bonariensis</i> (Pisces, atherinopsidae)

Several internal and external parasites have been reported in the wild population of the pejerrey, Odontesthes bonariensis, although most of previous studies have focused on taxonomy. The aims of this research were to describe the seasonal variation and the age prevalence pattern of the nematode Contracaecum sp., and to characterize the association between the pejerrey parasitic infestation with body condition score. Four samples, one per season, were collected during the years 2002 and 2003 in a shallow lake located in the southern area of Cordoba, Argentina (34° 36’S, 64° 24’W). The fishes caught were subject to age estimation using the Von Bertalanffy’s equation, the assessment of the relative weight (Wr) and the determination of abundance and intensity of the parasite infestation. The standard length average (n = 283) was 185,5 mm (range 38 - 380). The proportion of fishes with at least one parasite was 10,1%. The highest abundance (0,94) and prevalence (24,6%) were observed in summer, and the highest average intensity in autumn (5,7 parasites /fish). Fishes > 2 years old showed 5,99 more times (odds ratio IC95% 2,41 - 14,84) of being parasited with Contracaecum sp. in comparison to younger fishes. The Wr was lower for infested fishes (85,45; IC95% 81,82 - 89,08) in comparison to non infested specymens even after the statistical adjustment for season and age effects. Since Contracaecum sp. is zoonotic, the prevalence reported may pose a risk to humans due to the common habits of consuming uncontrolled fishes in recreational fisheries. In addition to that, parasitic infestation may also reduce body condition in fishes of commercial size.Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) - Instituto de Limnología "Dr. Raul A. Ringuelet" (ILPLA

Patrones de riesgo e implicancias de la presencia de <i>Contracaecum</i> sp. (Nematoda, anisakidae) en pejerrey <i>Odontesthes bonariensis</i> (Pisces, atherinopsidae)

Several internal and external parasites have been reported in the wild population of the pejerrey, Odontesthes bonariensis, although most of previous studies have focused on taxonomy. The aims of this research were to describe the seasonal variation and the age prevalence pattern of the nematode Contracaecum sp., and to characterize the association between the pejerrey parasitic infestation with body condition score. Four samples, one per season, were collected during the years 2002 and 2003 in a shallow lake located in the southern area of Cordoba, Argentina (34° 36’S, 64° 24’W). The fishes caught were subject to age estimation using the Von Bertalanffy’s equation, the assessment of the relative weight (Wr) and the determination of abundance and intensity of the parasite infestation. The standard length average (n = 283) was 185,5 mm (range 38 - 380). The proportion of fishes with at least one parasite was 10,1%. The highest abundance (0,94) and prevalence (24,6%) were observed in summer, and the highest average intensity in autumn (5,7 parasites /fish). Fishes > 2 years old showed 5,99 more times (odds ratio IC95% 2,41 - 14,84) of being parasited with Contracaecum sp. in comparison to younger fishes. The Wr was lower for infested fishes (85,45; IC95% 81,82 - 89,08) in comparison to non infested specymens even after the statistical adjustment for season and age effects. Since Contracaecum sp. is zoonotic, the prevalence reported may pose a risk to humans due to the common habits of consuming uncontrolled fishes in recreational fisheries. In addition to that, parasitic infestation may also reduce body condition in fishes of commercial size.Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) - Instituto de Limnología "Dr. Raul A. Ringuelet" (ILPLA

Composição e diversidade da ictiofauna do reservatório La Viña (Córdoba, Argentina)

Several dams have been built in central and north Argentina. There are more than 20 reservoirs in Córdoba province, with a total estimated surface area of around 15,000 ha. Although construction of dams continues, some aspects about the richness, abundance and diversity of ichthyofauna in many of these environments are unknown, which prevents adequate management of fish resources. The goal of this work was to evaluate specific richness and diversity of ichthyofauna in La Viña reservoir (31° 47' S and 65° 01' W, 1,050 ha, 846 m asl), one of the major reservoirs in Córdoba. Fifteen seasonal samplings were made in 1999-2002 using trawl nets and gillnets. A total of 3,242 specimens belonging to 7 species distributed in 5 orders and 5 families were caught. The tetra Astyanax eigenmanniorum (52.9%) and the silverside Odontesthes bonariensis (29.3%) were the most abundant species; the latter is the main target species for lake fishing and had greatest biomass (63.8%). Average diversity for all samples was H'T=1.63 (95% confidence interval 1.49 to 1.77). Shannon-Wiener and Simpson diversity indexes values were generally intermediate. Specific richness of La Viña reservoir was moderate compared with other impoundments in central and north Argentina.Na área central e norte da Argentina há uma importante quantidade de represas. Na província de Córdoba, existem, na atualidade, mais de 20 reservatórios que ocupam uma superfície aproximada de 15.000 ha. Embora a construção de represas continue em uma grande quantidade de ambientes, não se conhecem alguns aspectos da riqueza, abundância e diversidade da ictiofauna, dificultando a gestão e manejo dos recursos pesqueiros. O objetivo do trabalho foi avaliar a riqueza específica e a diversidade da ictiofauna do reservatório La Viña (31° 47’ S e 65° 01’ W, 1.050 ha, 846 msnm), um dos mais importantes de Córdoba. No período entre 1999-2002, realizaram-se 15 amostragens estacionais, utilizando-se redes de arrasto e de espera. Coletaram-se 3.242 indivíduos de 7 espécies distribuídas em 5 ordens e 5 famílias. Em função do número total de espécies, as de maior abundância foram lambari Astyanax eigenmanniorum (52,9%) e peixe-rei Odontesthes bonariensis (29,3%), sendo esta última espécie o objetivo da pescaria do lago e a que alcançou a maior biomassa (63,8%). Considerando o total da amostragem, a diversidade média foi de H’T = 1,63, com um intervalo de confiança (95%) de 1,49 a 1,77. No geral, os índices de diversidade de Shannon-Wiener e Simpson foram médios. Comparando com outros reservatórios da área central e norte da Argentina, a riqueza específica do reservatório La Viña é moderada.Facultad de Ciencias Naturales y Muse

Composition and diversity of ichthyofauna in La Viña reservoir (Córdoba, Argentina)

Several dams have been built in central and north Argentina. There are more than 20 reservoirs in Córdoba province, with a total estimated surface area of around 15,000 ha. Although construction of dams continues, some aspects about the richness, abundance and diversity of ichthyofauna in many of these environments are unknown, which prevents adequate management of fish resources. The goal of this work was to evaluate specific richness and diversity of ichthyofauna in La Viña reservoir (31° 47' S and 65° 01' W, 1,050 ha, 846 m asl), one of the major reservoirs in Córdoba. Fifteen seasonal samplings were made in 1999-2002 using trawl nets and gillnets. A total of 3,242 specimens belonging to 7 species distributed in 5 orders and 5 families were caught. The tetra Astyanax eigenmanniorum (52.9%) and the silverside Odontesthes bonariensis (29.3%) were the most abundant species; the latter is the main target species for lake fishing and had greatest biomass (63.8%). Average diversity for all samples was H'T = 1.63 (95% confidence interval 1.49 to 1.77). Shannon-Wiener and Simpson diversity indexes values were generally intermediate. Specific richness of La Viña reservoir was moderate compared with other impoundments in central and north Argentina

Composition and diversity of ichthyofauna in La Viña reservoir (Córdoba, Argentina)

Several dams have been built in central and north Argentina. There are more than 20 reservoirs in Córdoba province, with a total estimated surface area of around 15,000 ha. Although construction of dams continues, some aspects about the richness, abundance and diversity of ichthyofauna in many of these environments are unknown, which prevents adequate management of fish resources. The goal of this work was to evaluate specific richness and diversity of ichthyofauna in La Viña reservoir (31° 47' S and 65° 01' W, 1,050 ha, 846 m asl), one of the major reservoirs in Córdoba. Fifteen seasonal samplings were made in 1999-2002 using trawl nets and gillnets. A total of 3,242 specimens belonging to 7 species distributed in 5 orders and 5 families were caught. The tetra Astyanax eigenmanniorum (52.9%) and the silverside Odontesthes bonariensis (29.3%) were the most abundant species; the latter is the main target species for lake fishing and had greatest biomass (63.8%). Average diversity for all samples was H'T = 1.63 (95% confidence interval 1.49 to 1.77). Shannon-Wiener and Simpson diversity indexes values were generally intermediate. Specific richness of La Viña reservoir was moderate compared with other impoundments in central and north Argentina

FPGA implementation of a single channel GPS interference mitigation algorithm

The FPGA (Field-Programmable Gate Array) implementation of an adaptive filter for narrow band interference excision in Global Positioning Systems is described. The algorithm implemented is a delayed LMS (Least Mean Squares) adaptive algorithm improved by incorporating a leakage factor, rounding and constant resetting of the filter weights. This was necessary as the original adaptive algorithm had stability problems : the filter weights did not remain fixed, and tended to drift until they overflowed, causing the filter response to degrade. Each model was first tested in Simulink, implemented in VHDL (Verilog Hardware Description Language) and then downloaded to an FPGA board for final testing. Experimental measurements of anti-jam margins were obtained.Gabriel Bucco, Matthew Trinkle, Doug Gray and Wai-Ching Cheu