Universidad Nacional Agraria La Molina. Facultad de Pesquería. Departamento Académico de Acuicultura e Industrias Pesqueras | En el presente trabajo se evaluó el sistema de recirculación acuícola (RAS) para la producción intensiva de alevines de truchas arco iris (Orconhynchus mykiss) monitoreando la calidad del agua y los indicadores de producción. El funcionamiento del RAS se inicia con la captación del agua de una fuente natural subterránea (pozo) la cual ingresa al sistema de recirculación pasando por el filtro mecánico, el filtro biológico, desgasificador, UV y oxigenación; para luego ser distribuido a los tanques con peces y su retorno al inicio del sistema. Los resultados de la calidad del agua demostró el buen funcionamiento del sistema (biofiltro, filtro mecánico, UV, saturador de oxígeno y desgasificadores) el cual fue monitoreado y controlado de manera adecuada trabajando en conjunto con el manejo de los flujos de renovación de agua y el control sanitario de las truchas. Los principales indicadores de producción determinados y evaluados fueron: la mortalidad acumulada (1488 muertos, 0.99%), la tasa de crecimiento especifico (SGR) de los alevines obtuvo un valor de 9.29 inicialmente y llegó a 4.61 previo a la cosecha y el factor de conversión alimenticia (FCA) en promedio 0.65. La aplicación del sistema RAS ha permitido la reutilización del agua en un 75% a más y una producción máxima mensual de 400 mil alevines demostrando ser eficiente y más productivo que el sistema convencional abierto. | In the present work, the recirculating aquaculture system (RAS) was evaluated for the intensive production of rainbow trout fingerlings (Orconhynchus mykiss) by monitoring water quality and production indicators. The operation of the RAS begins with the collection of water from a natural underground source (well) which enters the recirculation system through the mechanical filter, the biological filter, degasser, UV and oxygenation; to later be distributed to the tanks with fish and its return to the beginning of the system. The results of the water quality demonstrated the proper functioning of the system (biofilter, mechanical filter, UV, oxygen saturator and degassers) which was adequately monitored and controlled working in conjunction with the management of water renewal flows and trout health control. The main production indicators determined and evaluated were: accumulated mortality (1488 deaths, 0.99%), the specific growth rate (SGR) of the fingerlings obtained a value of 9.29 initially and reached 4.61 prior to harvest and the factor of feed conversion (FCA) on average 0.65. The application of the RAS system has allowed the reuse of water by 75% or more and a maximum monthly production of 400,000 fingerlings, proving to be efficient and more productive than the open conventional system.

We tried to correlate the level of genetic introgression in native brown trout populations with some physicochemical and environmental features. Introgresión rates were calculated according the presence (assessed by PCR-RFLP as described by Mc Meel et al. 2001) of the LDH C1*90 allele in the populations, which is fixed in central European populations used for restocking, whereas LDH C1*100 is the fixed allele in wild Mediterranean populations in the area of study. Water quality variables were obtained from Confederación Hidrográfica del Ebro data in 10-year series before sampling. Physicochemical characteristics as conductivity, pH, bicarbonates, temperature and Oxygen saturation were analyzed. Average, minimum and maximum, standard deviation and coefficient of variation were calculated for each of the above parameters. Populations were classified as wild (0% introgresión), low affected (less than 10% individuals), highly affected (10-50%) and severely affected (more than 50%). We found that highly affected populations are generally associated to higher minimum temperature and pH as well as to wide oscillations in oxygen saturation levels. Success in restocking using stocks of Atlantic domestic trout is strongly influenced by environmental features. Fortunately, wild populations show a better adaptation being able to colonise the most adverse environments. Restocking policies should be fully revised to preserve wild trout populations.

We tried to correlate the level of genetic introgression in native brown trout populations with some physicochemical and environmental features. Introgresión rates were calculated according the presence (assessed by PCR-RFLP as described by Mc Meel et al. 2001) of the LDH C1*90 allele in the populations, which is fixed in central European populations used for restocking, whereas LDH C1*100 is the fixed allele in wild Mediterranean populations in the area of study. Water quality variables were obtained from Confederación Hidrográfica del Ebro data in 10-year series before sampling. Physicochemical characteristics as conductivity, pH, bicarbonates, temperature and Oxygen saturation were analyzed. Average, minimum and maximum, standard deviation and coefficient of variation were calculated for each of the above parameters. Populations were classified as wild (0% introgresión), low affected (less than 10% individuals), highly affected (10-50%) and severely affected (more than 50%). We found that highly affected populations are generally associated to higher minimum temperature and pH as well as to wide oscillations in oxygen saturation levels. Success in restocking using stocks of Atlantic domestic trout is strongly influenced by environmental features. Fortunately, wild populations show a better adaptation being able to colonise the most adverse environments. Restocking policies should be fully revised to preserve wild trout populations