Growth under laboratory conditions of wild juvenile black-spot sea bream (Pagellus bogaraveo B.)

As an alternative to the culture of traditional fish, experiments have been started with black-spot sea bream (Pagellus bogaraveo) and are summarized here. Two groups of bream (B-1 and B-2) with 63 fish of mean weight 173 g and 67fish of mean weight 217 g, respectively, were captured on the NW coast of Spain between September and December 1991, transported to the laboratory, and maintained in 12 m tanks. After about 30 days acclimation, lengths and weights of all fish were measured. These measurements were repeated at 2 month intervals,for 14 months in the first group and 10 months in the second. The mean weights reached at the end of these periods were 462 g and 383 s. respectively. Fish were fed with laboratory prepared moist food. and the amount eaten daily was controlled. Survival rate at the end of the experiment was 90.5% in group B-1 and95.5% in group B-2. Temperature, measured daily, ranged from 12ºC to 20°C. This paper provides information on the capture, transport, acclimation and maintenance of the fish throughout the experiment.Versión del editor0,000

Reproduction of blackspot seabream, pagellus bogaraveo B. in captivity

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Ongrowing of juvenile blackspot seabream Pagellus bogaraveo (Brünnich, 1768), in tanks and cages

We present results obtained from ongrowing blackspot seabream Pagellus bogaraveo (Brünnich, 1768), in cages and tanks. This experiment, conducted over the course of 12 months, used two batches of fish born in captivity, with individuals ranging from 30 to 200 g, whose average initial weight was 33.94±6.56 g, Daily growth rates were calculated, resulting in 0.36 % in tanks and 0.46 % in cages. Fish growth curves were drawn up for both culture systems, achieving the following equations: y = 33 e0,1733x (R²=0,9887) in cages and y=34,65 e0,13x (R²=0,9927) in tanks. The comparison of the slopes of these growth curves (t-test) showed that growth is considerably greater in cages than in tanks on land.Se muestran los resultados obtenidos en el engorde de besugo Pagellus bogaraveo (Brünnich, 1768) mantenidos en jaulas flotantes en el mar y en tanques emplazados en tierra y con el que se consiguieron incrementos de entre 30 y 200 g en el peso de los ejemplares. La experiencia, que tuvo una duración de 12 meses, se realizó con dos lotes de peces nacidos en cautividad y con un peso medio inicial de 33,94±6,56 g. Se calcularon las tasas de crecimiento diario, que fueron del 0,36 % en los tanques y del 0,46 % en las jaulas, y se determinaron las curvas de crecimiento de los peces para los dos sistemas de cultivo, obteniéndose las ecuaciones y=33 e0,1733x (R²=0,9887) para las jaulas e y=34,65 e0,13x (R²=0,9927) para los tanques. La comparación de las pendientes de las curvas de crecimiento (test t) muestra que el crecimiento es significativamente mayor en las jaulas flotantes que en los tanques situados en tierra.Instituto Español de Oceanografí

Indicators of nutritional status of turbot Scophthalmus maximus (L., 1758) larvae

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Experience with ongrowing juvenile blackspot sea bream (Pagellus bogaraveo) born in captivity, in tanks at diferent temperatures

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Indicators of nutritional status of turbot Scophthalmus maximus (L., 1758) larvae

Se han analizado diferentes indicadores del estado nutricional de larvas de rodaballo Scophthalmus maximus (L., 1758) alimentadas de hasta 53 días de edad y se han comparado con los de otras larvas sometidas a condiciones de inanición. Los indicadores estudiados fueron longitud, peso seco, condición relativa larvaria, diámetro del otolito, histología digestiva de las larvas, contenido en ácidos grasos, ácido ascórbico, RNA, DNA Y proteínas. Los procesos de inanición se llevaron a cabo a los 3, 9, 16, 23 Y 27 días de edad y los análisis de estas larvas fueron comparados con los de larvas alimentadas de las mismas edades. Durante las primeras 24 horas de inanición, las goticulas lipídicas en las células epiteliales desaparecen por completo del intestino. Después, la condición relativa disminuye aproximadamente el 5% por día y el diámetro relativo del otolito se incrementa en el 5% por día. Se producen también disminuciones en el peso seco, el contenido proteico, los niveles de ácidos grasos 18:1Ω-9, 20:5Ω-3 (EPA) y los de otros ácidos grasos altamente insaturados (Ω-3 HUFA), y en la relación RNA/DNA. Sin embargo, la mayoría de los indicadores investigados muestran una alta variación, incluso entre las distintas experiencias de cultivo realizadas, por lo que se concluye que las gotículas de lípidos en las células epiteliales del intestino, la condición relativa y el diámetro relativo del otolito son las únicas variables que pueden ser útiles para detectar un proceso de inanición en larvas de rodaballo.Nutritional status indicators of larvae of turbot Scophthalmus maximus (L., 1758) were investigated in feeding and starving turbot larvae from hatching up to an age of 53 days. The study included the whole-larvae parameters of length, dry weight and relative condition; the organ-related characteristics otolith diameter and intestinal histology; and the biochemical indicators fatty acids, ascorbic acid, RNA, DNA and total protein. Starvation was started at day 3, 9, 16, 23 and 27, and starved larvae were compared with feeding larvae from the same rearing group. After onset of starvation, lipid droplets in the intestinal epithelial cells disappeared within 24 h. Later; the influence of starvation also became apparent in most of the other indicators studied. Relative condition decreased by about 5%/day and relative otolith diameter increased by about 5%/day. A histologically observed total disappearance of chylomicrons and lipid droplets in the intestinal epithelial cells was in accordance with a drop in dry weight, protein content, and the fatty acids 18:1Ω-9, 20:5Ω-3 (EPA) and Ω-3 HUFA (Highly Unsaturated Fatty Acids), as well as the RNA/DNA ratio in starved larvae. However, most of the indicators studied showed such a high variation between individual rearing groups that only the parameters lipid droplets in intestinal epithelial cells, relative condition and relative otolith diameter seem useful for detecting starvation in turbot larvae.Instituto Español de Oceanografí