Historia de la piscicultura del pejerrey en Chascomús

El pejerrey Odontesthes bonariensis es uno de los peces de aguas continentales más emblemáticos de la Argentina y una de las especies más estudiada desde diferentes aspectos: ecológico, sistemático, morfológico, fisiológico, genético, etc. (López et al. 1991). Durante los años 1891 y 1892 se realizaron las primeras experiencias de piscicultura,lográndose por primera vez la reproducción artificial en 1904. Su amplia distribución actual es consecuencia de las siembras que se realizaron desde el antiguo Vivero de Piscicultura del Ministerio de Agricultura y Ganadería de la Nación y de la Estación Hidrobiológica del Ministerio de Asuntos Agrarios de la provincia de Buenos Aires, ambos establecimientos ubicados en la ciudad de Chascomús. En el presente trabajo se realiza una aproximación a la historia de la piscicultura del pejerrey en Chascomús, la que se divide en tres períodos: 1) Antecedentes de piscicultura, importancia de la pesca comercial en el sistema de lagunas Encadenadas de Chascomús y primeras medidas tomadas para conservar la explotación de las lagunas hacia fines del siglo XIX. 2) Etapa del antiguo Vivero (Ministerio de Agricultura de la Nación), desde 1904 hasta 1939. 3) Etapa de la Estación Hidrobiológica (Ministerio de Asuntos Agrarios, provincia de Buenos Aires), desde 1943 hasta el presente

Producción intensiva de juveniles de pejerrey (Odontesthes bonariensis)

The objective of this work is to produce Odontesthes bonariensis juveniles in an intensive system. The experience lasted 196 days and during this, survival, growth, and production were studied. The first 16 days 29.000 hatched larvae were kept outdoors in two circular tanks of 2.000 liters each. They were fed with zooplankton, Artemia and artificial food. The total number of individuals obtained was 23.000, these were transferred to 100 m2 pond previously fertilized where they were reared during 180 days. The initial density was of 230 ind/m2 with a total average length of 15,03mm (±0,60 standard deviation) and average weight of 0,024 g.(±0,0041 standard deviation). The juveniles were fed 4 times a day with artificial food. Samples were taken in order to calculate length and weight growth, at the end of experiment survival and production were calculated. The final number of juveniles obtained was 16.503 with a final average length of 110,28mm. (±17,88 standard deviation) and average weight of 11,28g(±6,07standard deviation). The food conversion rate was 1,31. Survival rate was 71,75 %. The final production was 19.418,3 Kilogram/hectare after 180 days of rearing. These results show that massive production of juveniles is possible. The high density used, the final weight reached and the high percentages of survival allowed the biggest pejerrey juvenile production in Argentina after 196 days of rearing.Facultad de Ciencias Naturales y Muse

Producción intensiva de juveniles de pejerrey (Odontesthes bonariensis)

The objective of this work is to produce Odontesthes bonariensis juveniles in an intensive system. The experience lasted 196 days and during this, survival, growth, and production were studied. The first 16 days 29.000 hatched larvae were kept outdoors in two circular tanks of 2.000 liters each. They were fed with zooplankton, Artemia and artificial food. The total number of individuals obtained was 23.000, these were transferred to 100 m2 pond previously fertilized where they were reared during 180 days. The initial density was of 230 ind/m2 with a total average length of 15,03mm (±0,60 standard deviation) and average weight of 0,024 g.(±0,0041 standard deviation). The juveniles were fed 4 times a day with artificial food. Samples were taken in order to calculate length and weight growth, at the end of experiment survival and production were calculated. The final number of juveniles obtained was 16.503 with a final average length of 110,28mm. (±17,88 standard deviation) and average weight of 11,28g(±6,07standard deviation). The food conversion rate was 1,31. Survival rate was 71,75 %. The final production was 19.418,3 Kilogram/hectare after 180 days of rearing. These results show that massive production of juveniles is possible. The high density used, the final weight reached and the high percentages of survival allowed the biggest pejerrey juvenile production in Argentina after 196 days of rearing.Facultad de Ciencias Naturales y Muse

Un aporte para la enseñanza en las clases de Biología: las estrategias reproductivas de peces de lagunas bonaerenses

En este trabajo se propone un taller que aborde aspectos de la Biología de la Reproducción y el Desarrollo de las especies de peces más comunes de las lagunas bonaerenses. Entre los objetivos, se propone que los participantes conozcan la diversidad de peces que se encuentran en los ecosistemas lagunares de la provincia de Buenos Aires, comprendan las diferentes estrategias reproductivas que se establecen entre las distintas especies , observen y comparen aspectos anatómicos y fisiológicos del sistema reproductor y conozcan el desarrollo embrionario de los peces, tomando como ejemplo el pejerrey (Odontesthes bonariensis).Trabajos del área Ciencias NaturalesDepartamento de Ciencias Exactas y Naturale

Producción intensiva de ovas embrionadas de pejerrey (<i>Odontesthes bonariensis</i>) a partir de reproductores mantenidos en cautiverio

The aim of this work was the obtainment of Odontesthes bonariensis eggs from broodstocks reared in captivity since them hatched. The experiment took place from September 2005 to April 2006 during this time fish were kept in two circular tanks of 20 m2 (A1 and A2), with water salinity of 9 g/l and 3,6 times/day water volume changes. Water temperature varied from 17 to 22,5ºC. Broodstocks were fed with artificial food twice a day at 1% of body weight/day. The initial densities were 20,4 (A1) and 18,7 (A2) ind/m2. The male/female relationship was 1,02 (A1) and 0,86 (A2). Mean standard length of A1 reproducer was 293,1mm and 286,3mm in A2. Mean weight was 322 g (A1) and 306,4 g (A2). From A1 7.868.550 eggs with a 74,31 % fertilization rate and 6.061.790 with 75,11 % fertilization rate in A2 were obtained. During the first fifteenth of October the greater percentage of eggs was collected 25.01 % in A1 and 29.14 in A2. Each A1 female spawned 39.942 eggs in average and 32.208 in A2. Reproducers survival rates were 96,98 % and 94,66 % (A1 and A2). Finally we think that massive egg production with a high fertilization rate is possible from high densities of reproducers reared in captivity.Facultad de Ciencias Naturales y Muse

Producción intensiva de ovas embrionadas de pejerrey (<i>Odontesthes bonariensis</i>) a partir de reproductores mantenidos en cautiverio

The aim of this work was the obtainment of Odontesthes bonariensis eggs from broodstocks reared in captivity since them hatched. The experiment took place from September 2005 to April 2006 during this time fish were kept in two circular tanks of 20 m2 (A1 and A2), with water salinity of 9 g/l and 3,6 times/day water volume changes. Water temperature varied from 17 to 22,5ºC. Broodstocks were fed with artificial food twice a day at 1% of body weight/day. The initial densities were 20,4 (A1) and 18,7 (A2) ind/m2. The male/female relationship was 1,02 (A1) and 0,86 (A2). Mean standard length of A1 reproducer was 293,1mm and 286,3mm in A2. Mean weight was 322 g (A1) and 306,4 g (A2). From A1 7.868.550 eggs with a 74,31 % fertilization rate and 6.061.790 with 75,11 % fertilization rate in A2 were obtained. During the first fifteenth of October the greater percentage of eggs was collected 25.01 % in A1 and 29.14 in A2. Each A1 female spawned 39.942 eggs in average and 32.208 in A2. Reproducers survival rates were 96,98 % and 94,66 % (A1 and A2). Finally we think that massive egg production with a high fertilization rate is possible from high densities of reproducers reared in captivity.Facultad de Ciencias Naturales y Muse

Producción intensiva de ovas embrionadas de pejerrey (<i>Odontesthes bonariensis</i>) a partir de reproductores mantenidos en cautiverio

The aim of this work was the obtainment of Odontesthes bonariensis eggs from broodstocks reared in captivity since them hatched. The experiment took place from September 2005 to April 2006 during this time fish were kept in two circular tanks of 20 m2 (A1 and A2), with water salinity of 9 g/l and 3,6 times/day water volume changes. Water temperature varied from 17 to 22,5ºC. Broodstocks were fed with artificial food twice a day at 1% of body weight/day. The initial densities were 20,4 (A1) and 18,7 (A2) ind/m2. The male/female relationship was 1,02 (A1) and 0,86 (A2). Mean standard length of A1 reproducer was 293,1mm and 286,3mm in A2. Mean weight was 322 g (A1) and 306,4 g (A2). From A1 7.868.550 eggs with a 74,31 % fertilization rate and 6.061.790 with 75,11 % fertilization rate in A2 were obtained. During the first fifteenth of October the greater percentage of eggs was collected 25.01 % in A1 and 29.14 in A2. Each A1 female spawned 39.942 eggs in average and 32.208 in A2. Reproducers survival rates were 96,98 % and 94,66 % (A1 and A2). Finally we think that massive egg production with a high fertilization rate is possible from high densities of reproducers reared in captivity.Facultad de Ciencias Naturales y Muse

Variaciones estacionales e históricas de las especies ícticas de la laguna Chascomús

In the last five decades the ictiofauna of Chascomús Shallow lake has been studied in quite detail. Between 1999 and 2000 monthly samples of fish with fyke nets were taken. Thus obtaining the cuali-quantitative composition of each sample taken. These were used to assess the variations between sites and seasons of the year. Among the 17 species caught Porteño, pejerrey and sabalito were present in all the samples taken, wichwere dominant and wich represented 51%, 24% and 14% of the total number respectively, and 28% 10% and 37% in weight. Their composition was similar in all stations sampling at every date. Notwithstanding this differences between abundance (CPUEn) and the extracted biomass (CPUEw) were observed. The capture by unit of total effort decreased from winter to autumn. The average (CPUEw) for Chascomús was above the values corresponding to 47 samples taken in different water bodies from Buenos Aires pampas. Comparing the results with the obtained historical data throughout 40 years it was observed that the percentage of the planctophagous species, pejerrey and mandufia marked a declining tendency. On the other handthe biomass of the porteño and sabalito showed a market increase. Significant correlations between these changes and the antropogénic impact were observed.Instituto de Limnología "Dr. Raúl A. Ringuelet

Variaciones estacionales e históricas de las especies ícticas de la laguna Chascomús

In the last five decades the ictiofauna of Chascomús Shallow lake has been studied in quite detail. Between 1999 and 2000 monthly samples of fish with fyke nets were taken. Thus obtaining the cuali-quantitative composition of each sample taken. These were used to assess the variations between sites and seasons of the year. Among the 17 species caught Porteño, pejerrey and sabalito were present in all the samples taken, wichwere dominant and wich represented 51%, 24% and 14% of the total number respectively, and 28% 10% and 37% in weight. Their composition was similar in all stations sampling at every date. Notwithstanding this differences between abundance (CPUEn) and the extracted biomass (CPUEw) were observed. The capture by unit of total effort decreased from winter to autumn. The average (CPUEw) for Chascomús was above the values corresponding to 47 samples taken in different water bodies from Buenos Aires pampas. Comparing the results with the obtained historical data throughout 40 years it was observed that the percentage of the planctophagous species, pejerrey and mandufia marked a declining tendency. On the other handthe biomass of the porteño and sabalito showed a market increase. Significant correlations between these changes and the antropogénic impact were observed.Instituto de Limnología "Dr. Raúl A. Ringuelet

Variaciones estacionales e históricas de las especies ícticas de la laguna Chascomús

In the last five decades the ictiofauna of Chascomús Shallow lake has been studied in quite detail. Between 1999 and 2000 monthly samples of fish with fyke nets were taken. Thus obtaining the cuali-quantitative composition of each sample taken. These were used to assess the variations between sites and seasons of the year. Among the 17 species caught Porteño, pejerrey and sabalito were present in all the samples taken, wichwere dominant and wich represented 51%, 24% and 14% of the total number respectively, and 28% 10% and 37% in weight. Their composition was similar in all stations sampling at every date. Notwithstanding this differences between abundance (CPUEn) and the extracted biomass (CPUEw) were observed. The capture by unit of total effort decreased from winter to autumn. The average (CPUEw) for Chascomús was above the values corresponding to 47 samples taken in different water bodies from Buenos Aires pampas. Comparing the results with the obtained historical data throughout 40 years it was observed that the percentage of the planctophagous species, pejerrey and mandufia marked a declining tendency. On the other handthe biomass of the porteño and sabalito showed a market increase. Significant correlations between these changes and the antropogénic impact were observed.Instituto de Limnología "Dr. Raúl A. Ringuelet