Consulta: subjectFacets:"Spatial variations"
Registros recuperados: 14
Data/hora: 06/06/2024 07:46:06

Effects of age and environment on the summer mortality in cupped oyster Crassostrea gigas during the first two years
Provedor de dados: 5
Autores: Degremont, Lionel; Boudry, Pierre; Soletchnik, Patrick; Bedier, Edouard; Ropert, Michel; Samain, Jean-francois.
Three successive generations were produced between 2001 and 2003 to assess to what extent genetic variability exists for survival in juvenile oysters Crassostrea gigas. For each generation, two groups were selected for their high ("R" for resistant) and low ("S" for susceptible) survival. Significant differences in mortality were observed during the first year in Riviere d'Auray (RA) (Brittany-France). However, low and similar mortality were observed for both groups, with no significant difference between groups in the first and second generation in this site, where the first summer is the critical, sensitive period with a clear age effect. In Baie des Veys (BDV) (Normandie-France), where mortalities usually mainly affect adults, mortality between groups,...
Tipo: Text
Palavras-chave: Crassostrea gigas; Spat; Spatial variations; Survival; Rearing; Mollusc culture; Marine molluscs; Environmental factors; Nursery grounds; Mortality causes; Biological age; Aquaculture techniques.
Ano: 2005
URL: http://archimer.ifremer.fr/doc/2005/acte-3385.pdf

Ontogenetic and spatial variation in the diet of hake (Merluccius merluccius) in the Bay of Biscay and the Celtic Sea
Provedor de dados: 5
Autores: Mahe, Kelig; Amara, R; Bryckaert, T; Kacher, M; Brylinski, J.
Analysis of the diet of trawl-caught hake (Merluccius merluccius) from three locations in the Bay of Biscay and the Celtic Sea in autumn 2001 showed that small hake fed almost exclusively on crustaceans (mainly euphausiids), but that there was a significant shift towards a fully piscivorous diet in hake &gt; 23 cm. A change in fish prey was also size-dependent, because smaller hake (&lt; 30 cm) preyed on small pelagic fish (3-12 cm), such as horse mackerel, anchovy, and pilchard, and larger hake on larger demersal prey (12-23 cm), such as blue whiting. There was a significant positive relationship between hake and fish prey length. In terms of fish prey selectivity, hake exhibited particular preference for small pelagic prey (anchovy, pilchard, and...
Tipo: Text
Palavras-chave: Spatial variations; Prey selectivity; Northeast Atlantic; European hake; Diet; Cannibalism.
Ano: 2007
URL: http://archimer.ifremer.fr/doc/2007/publication-3849.pdf

Diversity and spatial heterogeneity of mangrove associated sponges of Curaçao and Aruba
Provedor de dados: 16
Autores: Hunting, E.R.; Soest, R.W.M. van; Geest, H.G. van der; Vos, A.; Debrot, A.O.
Sponges are major epibionts of mangrove roots in the Caribbean. Mangrove sponge communities in the Caribbean mainly consist of species that are typical to this habitat and community compositions often differ from those found on coral reefs nearby. Heterogeneity in species distributions between locations and within locations between roots is often reported. This study quantifies the diversity and abundance of mangrove associated sponges in the inner bays of Curaçao and Aruba and correlates variability of regional sponge diversity with environmental variables measured along the surveyed sites. Tannin concentrations vary between mangrove roots, and were correlated to sponge cover as a possible cause for habitat heterogeneity on a smaller scale. A total of 22...
Tipo: Article / Letter to the editor
Palavras-chave: Epibionts; Heterogeneity; Mangroves; Spatial variations; Sponges; Tannins; 42.72.
Ano: 2008
URL: http://www.repository.naturalis.nl/record/291892

Exploitation et optimisation de la production des cystes du crustacé "Artemia tunisiana" (bowen et sterling, 1978) dans la saline de Sfax
Provedor de dados: 20
Autores: Aloui, N.; Amorri, M.
La saline de Sfax constitue le meilleur site pour l’exploitation et la production d’Artemia en Tunisie. La production de cystes est exploitée chaque année pour être utilisée dans l’alimentation des larves de poissons. Cette production est estimée à 30 kg de cystes poids sec. Toutefois, lors de nos campagnes de récolte, nous avons enregistré de grandes pertes de cystes occasionnées par les vents emportant les cystes qui seront mélangés avec le sable.    Afin de minimiser les pertes et optimiser la production naturelle de la saline, nous avons jugé utile, d’installer des barrages dans les coins des bassins à Artemia pour s’opposer à l’action du vent. Par ailleurs, nous avons fait un suivi mensuel de l’abondance des cystes récoltés et de quelques paramètres...
Tipo: Journal Contribution
Palavras-chave: Barriers; Brine shrimp culture; Dissolved oxygen; Environmental conditions; Exploitation; Feeding; Fish larvae; Food organisms; Salinity effects; Spatial variations; Temporal variations; Cysts; Artemia culture; Prawns and shrimps; Crustaceans; Artemia.
Ano: 2009
URL: http://hdl.handle.net/1834/4747

Variaciones espacio - temporales en la cobertura del macrofitobentos en un área costera al norte de Ciudad de La Habana, Cuba.
Provedor de dados: 20
Autores: Alfonso, Y.; Martínez-Daranas, B.
Se realizó el inventario y la evaluación de la cobertura y la estructura de la flora marina de una ensenada en la costa NW de la Habana durante un año. Los muestreos se realizaron con una frecuencia trimestral y se evaluó la cobertura de grupos morfo-funcionales en cuadrados de 625 cm2 lanzados en transectos paralelos. Se identificaron en total 47 taxones infragenéricos de plantaas marinas, de las cuales 20 especies y tres variedades fueron Chlorophyta, 19 Rhodophyta, 5 Ochrophyta, una cianobacteria y dos Magnoliophyta. Halimeda opuntia (L.) J. V. Lamouroux, Caulerpa racemosa (Forsskal) J.Agardh, Dictyopteris delicatula J. V. Lamouroux Gracilaria mammillaris (Montagne) Howe y Aglaothamnion herveyi (M. Howe) Aponte, D. L. Ballantine y J. N. Norris,...
Tipo: Journal Contribution
Palavras-chave: 1222; Check lists; Spatial variations.
Ano: 2009
URL: http://hdl.handle.net/1834/4000

La comunidad bentónica intermareal de Brachidontes rodriguezii (D'Orb.) y su relación con el efluente cloacal de la ciudad de Mar del Plata (38° S)
Provedor de dados: 20
Autores: Vallarino, E.A.
El mitílido Brachidontes rodriguezii es el organismo estructurante de una compleja comunidad intermareal que se desarrolla sobre los sustratos intermareales duros (cuarcíticos y limo- loessoides), en el sudeste de la provincia de Buenos Aires (Argentina). El presente estudio se desarrolló durante los años 1997, 1998, 1999 y 2000, en áreas costeras de los alrededores de Mar del Plata (Camet); Santa Clara del Mar (Santa Elena) y en Mar de Cobo. Se determinaron cuatro estaciones de muestreo en la zona de Camet (área impactada) y dos áreas control en Santa Elena y Mar de Cobo. En cada muestreo se tomaron muestras biológicas, de sedimento retenido y de Materia orgánica, así como de las variables ambientales: temperatura, salinidad, oxígeno disuelto, turbidez y...
Tipo: Theses and Dissertations
Palavras-chave: Intertidal environment; Biological sampling; Environmental factors; Pollution effects; Spatial variations; Seasonal variations; Biomass; Intertidal environment; Environmental factors; Biomass.
Ano: 2002
URL: http://hdl.handle.net/1834/2955

Towards the development of environmental indices for the Namibian shelf, with particular reference to fisheries management.
Provedor de dados: 20
Autores: Bartholomae, Ch.; Van der Plas, A.
The Namibian Ministry of Fisheries and Marine Resources has the task of collecting and providing relevant oceanographic information for management of their fisheries. However, quality information is difficult to provide because of the complexity of the processes involved in the Namibian marine ecosystem. Nonetheless, there are oceanographic data available that can contribute to fisheries management by improving the general understanding of important oceanographic processes related to fisheries. The focus of this paper is on the development of simple environmental indices that can serve as a measurement or proxy of the state or intensity of certain important oceanographic processes or variables for temporal comparison. These indices relate to oceanographic...
Tipo: Journal Contribution
Palavras-chave: Fisheries management; Marine resources; Oceanographic data; Chlorophylls; Upwelling; Spatial variations; Sardine fisheries; Water temperature; El Nino phenomena; Ecosystems; Fish stocks; Surface temperature; Oxygen; Phytoplankton; Biomass; Seasonal variations; Fronts; Perturbations; Commercial fisheries; Catchability; Remote sensing; Chlorophylls; Dissolved oxygen; Environmental impact.
Ano: 2007
URL: http://hdl.handle.net/1834/4971

Significado paleobiológico y paleoambiental de las concentraciones holocenas de Heleobia (Gastropoda) presentes en el sudeste de la provincia de Buenos Aires.
Provedor de dados: 20
Autores: De Francesco, C.G.
The aim of the present work is to determine the paleobiological and paleoenvironmental significance of fossil concentrations of Heleobia Stimpson, 1865 (Gastropoda) deposited during the last transgressiveregressive cycle along the Atlantic coast. The work was divided into two stages : 1) the analysis of living populations of H. australis (d'Orbigny), I-1. conexa (Gaillard) and H. parchappii (d'Orbigny) in two estuarine environments from the southeastern coast of the Buenos Aires Province (Mar Chiquita coastal lagoon and Quequen Grande estuary) in order to know the range of variation of the main biological and ecological factors and 2) the paleoecological analysis of three holocene sequences from the same region (mouth of the Quequen Grande River, Mouth of...
Tipo: Theses and Dissertations
Palavras-chave: Palaeoenvironments; Palaeoecology; Spatial variations; Comparative studies; Taxonomy; Morphometry; Abundance; Taxonomy; Http://aims.fao.org/aos/agrovoc/c_7631.
Ano: 2002
URL: http://hdl.handle.net/1834/2971

Spatial and temporal characterization of soft bottom polychaetes in a shallow tropical bay (colombian Caribbean)
Provedor de dados: 20
Autores: Guzmán-Alvis, A.I.; Lattig, P.; Ruíz, J.A.
The spatial and temporal variations of the polychaete assemblages were studied within and off a shallow (10-25 m) tropical bay (Bahía de Portete). The polychaete abundances at family level and their trophic mechanisms were used for this purpose. Sediment samples were collected at six stations in this bay during the wet and dry seasons. Multivariate analysis indicated that off- Bay polychaete assemblages were different from the bay ones; this spatial variation was related to sedimentary characteristics, depth and turbid-water conditions. On the other hand, these assemblages did not show significant differences between the dry and wet seasons. The differences between these two assemblages were given specially by the Syllidae, Gonidadidae, Nephtyidae,...
Tipo: Journal Contribution
Palavras-chave: Trophic relationships; Benthic environment; Organic matter; Temporal variations; Spatial variations; Organic matter; Benthic environment; Http://aims.fao.org/aos/agrovoc/c_5387; Http://aims.fao.org/aos/agrovoc/c_877.
Ano: 2006
URL: http://hdl.handle.net/1834/1979

Dinámica de la metapoblación de almeja panopea Panopea abbreviata en los golfos norpatagónicos
Provedor de dados: 20
Autores: Zaidman, P.C.
Panopea abbreviata es el molusco bivalvo infaunal de mayor tamaño del Mar Argentino. Se distribuye desde Río de Janeiro (Brasil) hasta la Patagonia Argentina. En los golfos San Matías (GSM) y San José (GSJ), conforma una metapoblación que presenta una distribución discontinua, formada por una serie de poblaciones ubicadas a lo largo de las costas.Es el bivalvo más longevo explotado en el Atlántico Sur. En el GSM su pesquería comenzó en el año 2000 y, si bien la misma es incipiente, debido a las características biológico-poblacionales de P. abbreviata es un recurso que requiere de un manejo precautorio. Excepto por estudios preliminares sobre el crecimiento y el ciclo reproductivo, no se contaba con la información básica para manejo. El objetivo general del...
Tipo: Theses and Dissertations
Palavras-chave: Fishery biology; Marine molluscs; Population dynamics; Sustainable management; Age; Growth; Mortality rate; Recruitment; Population structure; Spatial variations; Sex composition; Reproductive cycle; Histology; Environmental conditions.
Ano: 2013
URL: http://hdl.handle.net/1834/5236

Variación espacial de la comunidad de peces  asociados a un canal de mangles en Cayo Coco, Cuba
Provedor de dados: 20
Autores: Salvat Torres, H.M.; Pina Amargós, F.; González Sansón, G.
En este trabajo se caracterizó la comunidad de peces asociados a un canal de mangle que comunica al mar  una laguna costera, ubicada en Cayo Coco, Ciego de Ávila. Se comparó la distribución de los peces en todo  el canal de mangle y se relacionó con los parámetros abióticos del área y las características del hábitat. Se  realizaron censos visuales con buceo libre y se midió el área de refugio y sombra en toda su extensión. Se  tomó la temperatura del agua, salinidad, profundidad, marea, velocidad de la corriente de marea,  transparencia del agua y  la fase lunar de esa noche. Se observaron 47 especies de peces, pertenecientes a  22 familias. Se observó que al inicio (más cerca del mar) del canal la abundancia de peces pequeños era  mayor que al final del...
Tipo: Journal Contribution
Palavras-chave: Spatial variations; Community fishing; Mangroves.
Ano: 2010
URL: http://hdl.handle.net/1834/4531

Variabilidad espacial y temporal de los remolinos oceánicos en la región suroccidental de Cuba
Provedor de dados: 20
Autores: Gutiérrez, Alina Rita; Álvarez Cruz, Amaury.
Un estudio de los remolinos oceánicos se realizó en la región SW de Cuba (19o-22oN, 80o40´- 86o30´W). Este comprendió la localización de los vórtices y sus escalas asociadas. La caracterización del campo de remolinos tuvo en cuenta su posición, orientación, diámetro y área. La variabilidad espacial y temporal de la serie de corrientes se determinó por el método de las componentes principales. La data primaria provino de los mapas de alturas dinámicas de 18 cruceros oceanográficos, de imágenes de corrientes obtenidas con el Modelo Global de Circulación Oceánica y Climatología Avanzada, y de una serie de corrientes de los satélites ERS1/2. Este estudio demostró que existen dos tipos de mecanismos orientadores de los remolinos oceánicos. La topografía...
Tipo: Journal Contribution
Palavras-chave: Oceanic eddies; Spatial variations; Temporal variations.
Ano: 2012
URL: http://hdl.handle.net/1834/4567

Dynamics of a macroalgal rocky intertidal community in the colombian Caribbean
Provedor de dados: 20
Autores: García, C.B.; Díaz-Pulido, G.
The macroalgal intertidal community at a tropical location (Punta de la Loma, Colombian Caribbean) was monitored at irregular intervals from 1992 to 1995. The highly diverse macroalgal community was relatively invariant in cover, taxa and biomass from small spatial scales (square centimeters). At larger spatial scales (square meters), however, there was a small but definitive seasonal pulse in dominance and composition. Sand intrusions over the rocky intertidal represents a strong disturbance reducing macroalgal cover during the dry season. Interannual variation was also detected. La Punta de la Loma appears to be influenced by the regional upwelling conditions.
Tipo: Journal Contribution
Palavras-chave: Dynamics; Intertidal environment; Seasonal variations; Spatial variations; Intertidal environment; Http://aims.fao.org/aos/agrovoc/c_3923.
Ano: 2006
URL: http://hdl.handle.net/1834/1977

Meiobenthos of the central Arctic Ocean with special emphasis on the nematode community structure
Provedor de dados: 27
Autores: Vanreusel, A.; Clough, L.M.; Jacobsen, K.; Ambrose, W.; Jivaluk, J.; Ryheul, V.; Herman, R.; Vincx, M.
We investigated the abundance of the meiobenthos and the biomass and community structure of the nematodes in the central Arctic Ocean along two separate transects during 1991 and 1994. Meiobenthos abundances ranged from &lt; 100 to 600 individuals per 10 cm², in the same order of magnitude as in other oligotrophic areas of the world's deep ocean. Nematodes were the numerically dominant meiofaunal group at every station. Nematode biomass ranged from &lt; 1 to 48 µg dry weight per 10 cm². A combination of water depth and latitude explained 55% of the variability among stations in nematode biomass and 67% of the variability of total abundance, implying that both vertical and advective fluxes are important sources of food to the meiofaunal communities. The...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Community composition; Marine invertebrates; Meiobenthos; Spatial variations; Zoobenthos; Monhystera; Nematoda [Nematodes]; Pitcairn I.
Ano: 2000
URL: http://www.vliz.be/nl/open-marien-archief?module=ref&refid=7425