No abstract

RESUMENEl objetivo de este estudio fue determinar el efecto del extracto líquido de Y. schidigera sobre la calidad del agua y prevención de la mortalidad del pargo rojo del Pacífico L. Peru, durante la transferencia del medio silvestre a condiciones del laboratorio. Se utilizaron tres tratamientos: extracto líquido concentrado 100% de Y. schidigera natural fue administrado en baja concentración (0,25 mg L -1 ) y alta concentración (0,75 mg L -1 ), además de un grupo control sin extracto. El extracto líquido fue administrado cada 72 h durante 28 días. Se encontró que el extracto Y. schidigera reduce la concentración de amonio producto de la excreción de los juveniles y la mortalidad del huachinango durante la aclimatación en un sistema de recirculación. Se recomienda el uso del extracto de yuca en una concentración de 0,75 mg L -1 para reducir el amonio y para una densidad máxima de 10,9 kg m -3 y con aireación.Palabras clave: Yucca schidigera, reducción de amonio, pargo, supervivencia. SUMMARYThe goal of this study was to determine the effect of the liquid extract of Yucca schidigera on water quality and survival of Pacific red snapper Lutjanus peru during its transfer from wild to laboratory conditions. Three experimental groups (0.00; 0.25 and 0.75 mg of Y. schidigera liquid extract per liter of culture) were tested with four replicates using water recirculating systems. The liquid extract was dispensed every 72 h during 28 days. It was proved that Y. schidigera extract could be effective to reduce ammonia nitrogen caused by biogenic source (excretion of fish juveniles) diminishing mortality of Pacific red snapper during acclimatization process. It is recommended the use of yucca extract concentration at a dose of 0.75 mg L -1 to reduce ammonia concentration in marine water for holding red snapper juveniles.

The ovarian development and the size at sexual maturity of Panulirus inflatus (Bouvier) of the Mexican Pacific and Gulf of California coastal waters were determined monthly between August 2001 and July 2002, using 191 females with carapace lengths (CLs) ranging from 44.94 to 94.18 mm. The seasonal cycle of ovarian development was divided into seven stages. The diameter of mature oocytes differed depending on ovarianmaturity stage (inactive = 44-115 µm, developing = 115-192 µm, ripe = 285-138 µm, re-developing = 85-158 µm, re-ripe = 133-183 µm, spawned = 29-87 µm, and recovering = 33-58 µm). Size of the smallest mature female was 53.02 mm CL, and the size at which 50% of females reached sexual maturity was estimated as 63.73 mm CL. Mature females were present every month, indicating a continuous reproductive pattern, although gonadosomatic index values were highest between February and July, with the maximum value in June. Results from this study indicate that the present minimum legal size, based on other spiny lobster species, is too large for P. inflatus.

In the present review, we have described aspects of the color of marine shrimp of importance in aquaculture (mainly Penaeus japonicus, Litopenaeus vannamei and Penaeus monodon) and in the world. It is generally described some ecological aspects and some factors that affect the color of the shrimp. It describes in a general way, ecological aspects and some factors that affect the color of the shrimp, as well as, specifi c aspects like the color change, the importance of the pigments in the color and the effect of the cooking and storage processes on the color of the shrimp. As well as some strategies that have been used to improve the color during the last decades are discussed. As well as the ability to select genetic lines of color shrimp.

ABSTRACT. The aim of this study was to evaluate the growth performance and survival of the Pacific white shrimp (Litopenaeus vannamei) with red tilapia hybrid (Red Florida: Red Yumbo) and spotted rose snapper (Lutjanus guttatus), stocked at different densities in intensive brackish water mix-culture systems compared with monoculture of shrimp. The experiment, conducted in twenty-one plastic tanks (750 L) was set up to evaluate water quality, growth; production and survival of shrimp, tilapia, and snapper, for 60 days. Three replicates were assigned to seven treatments: After 30 day, initial densities were unfolded (shrimp = 50 ind m ). Feeding rate was adjusted at 5 and 10% of body weight d -1 for shrimp and fish, respectively. The shrimp-tilapia mix cultures produced the higher nitrogen and phosphorus in water concentrations. Significant lower survival values were obtained for shrimp (60.0 ± 0.6%) cultured with snapper and for tilapia (79.0 ± 3.1%) reared with shrimp. Mean final biomass for shrimp, tilapia and snapper were higher for the mix-cultures (2.04, 7.7 and 2.9 fold increase, respectively) with respect to their initial biomass. The mix culture system allowed an increase in total production with lower feed conversion ratios, thus contributing with the system sustainability.