Catch rates of artisanal fisheries targeting Dasyatis guttata (Bloch & Schneider, 1801) in Todos os Santos Bay, northeastern Brazil

Dasyatis guttata has been target of artisanal fisheries in the coast of Bahia (Northeast Brazil) mainly by “arraieira” (gillnet) and “grozeira” (bottom long-line), but until now there is no stock assessment study. One of the important data for this knowledge is reliable indices of abundance. The aims of the present work are to: (1) estimate the best predictor for relative abundance (catch-per-unit-of-effort, CPUE), examining whether catch (production – kg) was related to: soak time of the gear, size of the gillnet or number of hooks, applying generalized linear model (GLM); (2) estimate the annual CPUE (kg/hooks and kg/m) averaged by gear; and (3) assess the temporal CPUE variance. Based on monthly sampling between January 2012 and January 2013, 222 landings by grozeira and 76 by arraiaiera were recorded in the two landing sites in Todos os Santos Bay, Bahia. A total of 14,550 kg (average = 44 kg/month) of D. guttata was captured. Models for both gears were highly significant (P < 0.0001). The analysis indicated that the most appropriate variable for CPUE analysis was the size of the gillnet (P < 0.001) and the number of hooks (P < 0.0001). Soak time of the gear was not significant for both gears (P = 0.4). High residual deviance expresses the complexity of the relations between ecosystem factors and other fisheries factors affecting relative abundance, which were not considered in this study. The average CPUE by grozeira was 6.39 kg/100 hooks ± 8.89 and by arraieira, 1.47 kg/100 m ± 1.66 over the year. Kruskal-Wallis test showed effect of the month on the mean grozeira CPUE (P = <0.001), but no effect (P = 0.096) on the mean arraieira CPUE. Grozeira CPUE values were highest in December and March, and lowest between May to August

Effect of larval density and feeding sequence on meagre (Argyrosomus regius Asso, 1801) larval rearing

[EN] Meagre, has been proposed as a candidate for marine finfish diversification on commercial aquaculture (Quémèner, 2002, Mateos, 2007). Despite of the elevated on growing potential, the most important bottleneck of this specie is related to the limited production of fry. Larval rearing of this species, is performed mainly adapting seabream culture techniques with different success (Roo et al., 2007) However, since limited information about the optimal feeding sequences and nutritional requirements of meagre is available, more research is needed on larval rearing protocols and nutrition. Present results (elevated larval growth rate, high survival, short rotifers period) are very promising for a successful implementation at industrial scale, which helps to solve the continues lack of fry of this specie in the Mediterranean and Canary islands.

Nuevas aportaciones al estudio de la organogénesis en larvas de corvina (Argyrosomus Regius Asso, 1801)

La corvina (Argyrosomus regius) es un teleósteo de la familia Scianidae, que en los últimos años ha despertado un gran interés en acuicultura por su rápido crecimiento y la calidad de su carne. A su vez, se trata de una de las especies denominadas ?nuevas? que no pertenecen a la familia de los espáridos, y permite diversificar la oferta de la piscicultura marina. Las primeras aportaciones al estudio histológico del desarrollo larvario de esta especie fueron realizados por Jiménez et al. (2007). El presente trabajo incrementa la información existente, durante los dos primeros meses de vida de esta especie, lo que permitirá optimizar el cultivo larvario. Para ello se analiza la relación entre el desarrollo de sistema digestivo, la vejiga natatoria y el sistema visual. Los resultado demuestran que la corvina es una especie de rápido desarrollo y muy susceptible a las condiciones de cultivo durante su fase larvaria, condicionando éstas su crecimiento. A su vez el presente estudio ratifica que las características morfológicas y la organogénesis están directamente relacionadas con la longitud de la larva, independientemente de la edad de la misma.

Efecto de la densidad larvaria y secuencial alimentaria en el cultivo larvario de corvina (Argyrosomus regius Asso, 1801) durante el primer mes de vida

Effect of larval density and feeding sequence on meagre (Argyrosomus regius Asso, 1801) larval rearing during the first month of life. In the present work two comparative studies of the effect of larval density and feeding sequence were performed. For such, two initial larval densities, 50 larvae.l-1 and 100 larvae.l-1 were established. In each density three feeding sequences were tested, applying different combinations of rotifers (Brachionus sp.) and Artemia sp. at different larval ages. After 30dah, standard length, dry weight and final survival were determined. Final survival was affected by initial larval density and feeding sequence. Lower density promotes better growth in dry weight and standard length for all the feeding sequences tested. In addition, feeding sequences affects larval growth and survival. Best result in survival (62,81±4,77%) were obtained with high larval density and T2 feeding sequence.

Optimización del protocolo de destete de corvina (Argyrosomus regius, Asso, 1801)

[EN] Argyrosomus regius is a new species of interest in aquaculture. Nevertheless, few are the works published on this species and less even in larvae culture and weaning. In this study 2 experiments were done, in tanks of 15 l, with larvae of 15 and 34 days of life, respectively to which 2 different protocols for their weaning were applied. The provided food consisted of a mixture of Artemia and microdiet to different concentration. In experiment A, the best results of growth were observed in treatment 1 and worse in treatment 3, nevertheless in the survival the opposite happened. In experiment B, the best results they were reached with larvae submitted to low density and with significant difference between treatment 1 and 2, in survival no significant differences were found between the different treatments.

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

L'attività pionieristica della Scuola bolognese nello studio e nell'utilizzo del cemento armato: 1875 - 1924. Tecniche costruttive e tipologie architettoniche

La ricerca mira ad indagare l’origine della Scuola ingegneristica bolognese ed il ruolo che essa ha avuto durante i suoi primi 50 anni di attività nella diffusione del calcestruzzo armato in Italia, ed in particolare nella città di Bologna, sia dal punto di vista teorico che architettonico. Il processo di sviluppo del cemento armato è stato indagato secondo i percorsi tipici della scienza e della tecnica: teoria e pratica appaiono nel periodo di sperimentazione del materiale assai lontane; soltanto grazie alla comprensione delle sue potenzialità costruttive e del modo di sfruttarle al meglio, esse iniziano a convergere. L’interesse specifico per la Scuola bolognese va quindi a collocarsi all’interno di un panorama assai più ampio, con l’obiettivo di comprendere se, e fino a quando, le due discipline proseguono lungo strade parallele o se, al contrario, esse godono di reciproche influenze.

Natural History on Blocks, in Bodies, and on the Hearth: Juvenile Science Literature and Games, 1850-1875.

This article examines the role of domestic spaces and images in mid-nineteenth-century science writing for children. Analyses of John Mill’s The Fossil Spirit, A.L.O.E.’s Fairy Frisket, John Cargill Brough’s The Fairy Tales of Science, Annie Carey’s “Autobiography of a Lump of Coal,” and an assortment of boxed games reveal a variety of ways in which overwhelming scientific concepts are domesticated. Moreover, juvenile science literature contributes this appeasing domestication to the broader scientific discourse, consistently framing natural history in terms of human experience.