El pejerrey Odontesthes bonariensis (Actinopterygii; Atherinopsidae) es un recurso pesquero relevante en varios países sudamericanos. En Argentina, su pesca permite la obtención de un importante volumen de proteína en numerosos ambientes acuáticos. La edad y talla de primera madurez sexual son parámetros fundamentales en el manejo de pesquerías. El propósito de la talla mínima de captura (TMC) es asegurar que los ejemplares hayan realizado al menos un ciclo reproductivo antes de ser capturados. El objetivo de este trabajo es determinar si la TMC vigente en la reglamentación argentina (200–250 mm de longitud total, LT) constituye una medida de gestión acertada en función del crecimiento de O. bonariensis. Se estimó el crecimiento en longitud de 72 poblaciones provenientes de embalses, lagos urbanos y lagunas mediante la ecuación de von Bertalanffy. Con un nivel de confianza...

The silverside Odontesthes bonariensis is the most important species in the fisheries of central Argentina. Capture per unit effort (CPUE), body condition, growth and feeding were studied for O. bonariensis in the Pampean shallow lake “Los Charos” (34º28´S, 64º23´W, 240 ha), located in Córdoba province. Four seasonal sampling procedures were carried out during 2002-2003. Floating gillnets and trawlnets were used to capture the fishes. Specimens captured (n= 2862) were ranged between 38 and 380 mm of standar length (StL). CPUE average was 74.3(±71,0) kg/20 hs/gillnets. The StL–weight relationship showed signifficant differences along the seasons (P< 0,01). The body score indices were within the reffered limits for this species. Growth was calculated by StL(t)= 459,8*[1–exp(-0,3105*(t-0,175))]. The StL–Total length (TL) ratio was TL(mm)= 8,23+StL*1,14 (n= 283; R2= 0,99)....

El pejerrey Odontesthes bonariensis es la especie más importante de las pesquerías del centro de Argentina. Se estudio la captura por unidad de esfuerzo (CPUE), la condición corporal, el crecimiento y la alimentación de O. bonariensis de la laguna pampeana Los Charos (34º28´S, 64º23´W, 240 ha), ubicada en la provincia de Córdoba. Se realizaron cuatro muestreos estacionales en el periodo 2002-2003. Para la captura de peces se utilizaron redes de arrastre y enmalle. Se capturaron 2862 ejemplares de un rango de talla comprendido entre 38 y 380 mm de longitud estándar (LSt). La CPUE promedio fue de 74,3(±71,0)kg/20 hs de tendido de red. La relación LSt-peso presentó diferencias significativas entre épocas del año (P< 0,01). Los índices de condición corporal estuvieron dentro de los límites de referencia de la especie. El crecimiento calculado fue: LSt(t)=459,8*[1–exp(-...

The action of menthol on physiological and anesthesiological variables in rainbow trout was evaluated. Clinically healthy juvenile trout were used, of both sexes, formed in group A (n=20) of 201.4 ± 60.1 g of weight subjected to 100 ppm/L of menthol in water at pH 6.4 and in group B (n=20) of 187.3 ± 48.6 g of weight exposed to identical concentration of menthol with the water adjusted to pH 8.0 with sodium bicarbonate. The fish were placed in containers with water at 16.7 °C and electrical conductivity of 0.10 mS cm-1. The work methodology was: 1) acclimatization of fish in a container without drug and recording of the basal respiratory rate (RR) after adopting a normal swimming behavior; 2) transfer to a second container with menthol and recording of times of loss of lateral balance and anesthesia; 3) transfer of anesthetized fish to a third container without drug and record of RR a...

The aim of this study was to evaluate the response of eugenol, propofol, isoflurane and lidocaine on physiological and anaesthesiologic variables of Cheirodon interruptus, the most widely used baitfish in Argentina. Six groups were formed: 25 mg/l eugenol, 50 mg/l eugenol, 300 mg/l lidocaine, 0.2 mg/l isoflurane, 0.4 mg/l isoflurane, and 5 mg/l propofol. The tests are carried out with water at a temperature of 18.03±2.1 °C, pH 6.87±0.18, dissolved oxygen 6.73±0.05 mg l-1 and conductivity 3.74±0.04 μS cm-. The initial weight (1.6±0.4 g) and total length (5.1±0.4 cm) were statistically similar between groups. The results indicate that eugenol and isoflurane meet the requirements that a good anaesthetic for use in fish should meet. For propofol and lidocaine, it is considered necessary to review the dosage to adapt its use in C. interruptus due to the long recovery time. The fish tr...