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 degrees 47' S and 65 degrees 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.

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.

Main diseases of pejerrey (Odontesthes bonariensis) in central Argentina

Argentina's central region includes an important area covered by shallow pampean lakes and dams. In these environments, fishing of pejerrey Odontesthes bonariensis Valenciennes, 1835 (Pisces, Atherinopsidae), the most important fresh-water fish of the country, is a relevant social activity and also a considerable economic resource. The main diseases found in this species were studied from 1992 to 2003 in the provinces of Córdoba, La Rioja and Santa Fe (30º and 35º S, 61º and 67º W). Most cases were registered in high temperature months. Lernaea sp and Aeromonas hydrophila were the etiological agents most frequently found. The trophic characteristics of the aquatic environments enhanced disease processes and caused massive death of O. bonariensis, due to complex hydrochemical interactions.

A região central de Argentina possui uma importante superfície coberta por represas e lagunas pampianas. Nestes ambientes, a pesca do peixe-rei Odontesthes bonariensis Valenciennes, 1835 (Pisces, Atherinopsidae), peixe de água doce mais importante do país, é uma atividade social relevante e de significado valor econômico. Estudaram-se as principais enfermidades que afetaram esta espécie de peixe no período de 1992-2003, nas províncias de Córdoba, La Rioja e Santa Fe (30 e 35ºS, 61 e 67ºW). A maior quantidade de casos foi registrada nos meses de temperaturas elevadas. Lernaea sp e Aeromonas hydrophila foram os agentes etiológicos mais importantes. As características tróficas particulares dos ambientes aquáticos estudados foram importantes por potenciarem alguns casos, mas em outros a causa da mortandade dos peixes esteve relacionada a complexas interações hidroquímicas.

[Analysis of the use of fluoridated dentifrices in Curitiba]. / Análise do consumo de dentifrícios fluorados em Curitiba.

The use of fluoride dentifrices in Curitiba (Brazil) was studied. The scholarity and socio-economical levels of the population were related to the use of fluoride dentifrices. The sample was composed of 155 persons, men and women. The results showed that 96.8% used dentifrices, but only 36.2% used fluoride dentifrices. The use of fluoride dentifrices was more significant among the higher socioeconomical and school levels.