Effect of rearing system intensiveness on biological features, culture performance and larval quality of meagre (Argyrosomus regius Asso, 1801) larvae

[EN]Meagre, Argyrosomus regius A., is a new species for aquaculture in south Atlantic and Mediterranean regions, that can reach a mean fresh weight of 8.02±2.51g. at 95dah. However, hatchery techniques must be improved to optimize culture performance and larval quality. Eggs of meagre were cultured under intensive (75 indv.l-1 in 2m3 tanks) and semi-intensive system (7.5 indv.l-1 in 40m3 tanks) to evaluate the effect of the intensification on biological features, stress resistance and skeletal deformities. At 30dah, despite in semi-intensive system reared larvae a higher total length (19.08± 2.3mm vs 16.00±1.54mm), dry body weight (13.09± 2.43mg vs 6.46±0.52mg), and survival after the activity test (75.0± 13.8% vs 53.3±11.5%) was found, the use of intensive systems were also very suitable and cost-effective for larval rearing of this species

Effect of culture system and diet in early larval stages over skeletal deformities development in gilthead sea bream

[ES] Main deformities such as lordosis, opercular deformities and upper/lower jaws shortening are considered as quality descriptors in commercial marine fish fry production and seem to be related with larval culture conditions in early larval stages. The aim of this work was to obtain information about the contribution of the diet and rearing system to the apparition of these abnormalities in gilthead sea bream (Sparus aurata) larvae in semi-industrial scale facilities. For that purpose, two different larval rearing systems semi-intensive and intensive were compared; besides, two different rotifer enrichments, DHA Protein Selco, (Inve Aquaculture, Dendermonde, Belgium) (R1) and Red Pepper Paste, (Bernaqua bvba, Turnhout, Belgium) were tested in the intensive system. Biochemical composition of larvae, preys and commercial products was analysed. At 50 days post hatching six hundred fish per treatment were individually studied under stereoscope and deformity frequency recorded. Besides at 95 days post hatching fry were soft X ray monitored. Both rotifer enrichment and rearing system affected survival, growth and deformity frequency. Rearing system did not affect total larvae fatty acid content except at 20 dah, where DHA were significantly higher and EPA significantly lower in Semi-intensive system. A significantly lower percentage of deformity rates together with better survival and growth were obtained in the semi-intensive system. In dietary treatment, rotifer enrichment significantly affected larval survival. R1 rotifers enrichment significantly (P<0.05) improved survival when compared to fed R2 larvae. The content of DPA was significantly (P<0.05) higher in R2 fed larvae reflecting the R2 rotifers content of this fatty acid. The level of this FA tended to decrease in concordance with the rotifers replacement by artemia in the diet. The effects n-3-HUFA and DPA (22:5n-6) over larval survival and skeletal deformities development is discussed.

Effect of rearing technique over skeletal deformities incidence and osteological development in red porgy Pagrus pagrus (Linnaeus, 1758) larvae

[EN]Red porgy is a candidate species for marine aquaculture diversification.The objective of the present study was to describe the osteological development and the occurrence of skeletal deformities in Pagrus pagrus larvae in relation to the intensification of the rearing system. Fish samples were periodically collected along the development from hatching to juveniles (95days after hatching). Osteological development and the presence of skeleton abnormalities were evaluated. X-ray studies revealed a high number of fish (Semi-intensive:38.8%; Intensive:46.5 %) with skeletal deformities. No significant interaction was found on the incidence of lordosis and fused vertebrae with the rearing tecnique. However, cranial abnormalities and kyphosis incidences were significantly higher in intensive system cultured red porgy. Also, the position of fused vertebrae in this fish was located mainly in the caudal area instead of pre-hemal area for semi-intensive system reared red porgy. Present results, suggest a relationship among feeding sequence, osteological development and deformity incidence and location in red porgy larvae

Effect of rearing techniques over, survival growth and skeletal abnormalities development in red porgy (Pagrus Pagrus) larvae

[EN] Red porgy is one of the most interested new species for Spanish and other Mediterranean countries. Although no industrial procedures for fry production has been yet developed. The aim of this work was to develop an industrial scale larval rearing protocols testing the viability of two different rearing techniques (semi-intensive vs intensive) in pilot scale facilities. The second objective was to obtain information about the contribution of rearing system to the apparition of morphological abnormalities such as lordosis, opercular deformities and upper/lower jaws shortening which are considered as quality descriptors in commercial marine fish fry production and seem to be related with larval culture conditions in early larval stages. For that purpose, two different larval rearing systems semi-intensive and intensive were compared using the same live feed enrichments. Biochemical composition of larvae, preys and commercial products was analysed. At 50 days post hatching six hundred fish per treatment was individually studied under stereoscope and abnormalities frequency recorded. At 95 days post hatching fry were soft X ray monitored as well. Survival and abnormalities frequency were similar between treatments although a better growth in terms of total length was obtained in the semi-intensive system.

Development of skeletal deformities in Gilthead sea bream (Sparus aurata) reared under different larval culture and dietary conditions

[EN] Main deformities such as lordosis, opercular deformities and upper/lower jaws shortening are considered as quality descriptors in commercial marine fish fry production and seem to be related at least with larval culture conditions in early larval stages. The aim of this work was to obtain information about the contribution of the diet and rearing system to the apparition of these abnormalities in gilthead sea bream (Sparus aurata) larvae in semi-industrial scale facilities. For that purpose, two different larval rearing systems semi-intensive and intensive were compared by duplicate and with the same live feed enrichments; besides, two different rotifer enrichments were tested in an intensive system. Biochemical composition of larvae, preys and commercial products was analysed. At 50 days post hatching six hundred fish per treatment were individually studied under stereoscope and abnormalities frequency recorded. At 95 days post hatching fry were soft X ray monitored as well. Survival and malformation frequency were significantly different between treatments, the effect of diet and system are discussed. A significantly lower percentage of deformity rates together with better survival and growth were obtained in the semi-intensive system, whereas the rotifer enrichment significantly affected larval survival.

Sea bream (Sparus aurata) intensive larval rearing : effects of microalgae and phages addition on the performance of the larvae

Máster Oficial en Cultivos Marinos. Trabajo presentado como requisito parcial para la obtención del Título de Máster Oficial en Cultivos Marinos, otorgado por la Universidad de Las Palmas de Gran Canaria (ULPGC), el Instituto Canario de Ciencias Marinas (ICCM), y el Centro Internacional de Altos Estudios Agronómicos Mediterráneos de Zaragoza (CIHEAM)