Hydrographic Conditions on Flemish Cap in July 2001

Hydrographic conditions on Flemish Cap in July 2001 are described after a survey with 94 CTD stations. Current conditions over Flemish Cap are described and compared with those observed in previous years. The superficial water around the Cap at shallow depth is Labrador Water that advents favoured by the anticyclonic circulation over the cape. Since the middle-1990s temperatures have been increasing until 1999. In 2001 the superficial waters (<100 m) are warmer (+1ºC) and saltier (+0.5) that the mean of 25 past years. In depth, a well-developed layer with temperatures around 3.5ºC and salinity 34.85 was observed all around the Cap over 200 m depth

Links between North Atlantic sardine recruitment and its environment

The year class strength of the Iberian sardine is regulated by hydroclimatic conditions in the North Atlantic. The low recruitment values of recent years have been caused by reduction of the reproductive stock. The reproductive strategy of the sardine,with autumn and spring spawning seasons, produces two recruitment periods each year. This reproductive strategy is adapted to the oceanographic regime in the area, with coastal upwelling between April and September, and a northerly surface coastal current in winter. Variations in the intensity and timing of the winter current affect the success of the autumn spawning and can lead to recruitment failure at the end of spring. Variations in the intensity and timing of the northerly wind component, which generates upwelling, control the success of spring spawning. On the basis of oceanographic data and yearly recruitment from 1975 to 1997, we try to analyze the recruitment variability induced by the marine climate to the Iberian sardine stock

Efeito de práticas culturais diversas na safra e contra safra do olival

Neste trabalho, apresentam-se resultados do efeito de um conjunto de práticas culturais sobre o fenómeno da safra contra safra em olival. Os ensaios foram instalados num olival da cv. Verdeal Transmontana em Suçães, Mirandela, após pré-selecção das árvores baseada na homogeneidade da copa. Os diferentes tratamentos incidiram sobre grupos aleatórios de 8 árvores e consistiram em: duas linhas de azoto, (1) com o elemento aplicado ao solo no fim do Inverno e (2) uma modalidade testemunha (sem l’4); três Unhas de potássio, (1) com aplicação ao solo, (2) aplicação ao solo + K aplicado por via foliar no Verão e (3) testemunha (sem K) três linhas de bom, (1) aplicado ao solo, (2) aplicado por via foliar três semanas antes da floração e(3) testemunha (sem B); e poda e vareja manual, com (1) poda severa em safra, (2) vareja manual e (3) testemunha (poda ligeira e colheita mecânica). Comparam-se os valores de produção obtidos na colheita 2003/04 (ano zero) com os valores da colheita seguinte (04/05). Na colheita de 03/04, um total de 72 árvores marcadas produziram eu’ média 23.3 kg de azeitona/árvore. Em 04/05, as mesmas 72 árvores produziram 6.5 kg/árvore, evidenciando um ano de safra seguido de contra safra. A modalidade com aplicação de N filo atenuou a contra safra. A produção média foi ligeiramente inferior na modalidade fertilizada, se bem que as diferenças não apresentem significado estatístico (wCO.05). As modalidades com aplicação de potássio apresentaram valores médios ligeiramente superiores à modalidade sem K, embora as diferenças também não tenham sido significativas. A aplicação de B foliar originou um estimulo superior na produção comparativamente aos cultos elementos e à aplicação do próprio elemento ao solo, Contudo, devido a elevada variabilidade experimental as diferenças também aio foram significativas. Poda severa em ano de safra e vareja manual produziram 3.8 e 3.6 kg de azeitona/árvore, respectivamente, valores significativamente inferiores à modalidade testemunha em que se atingiram 8.2 kg/árvore. Assim, baseados apenas na produção de azeitona e um ano após a instalação dos ensaios, conclui-se que a poda e a vareja exerceram um feito mais evidente e imediato no fenómeno da safra e contra safra que a gestão de fertilidade do solo e do estado nutritivo das árvores

The stock of Atlanto-Iberian sardine: possible causes of variability

Fluctuations in the Iberian stock in the period 1980-1989 have been examined, taking into account what is known of the biology of the species, oceanic and atmospheric parameters, and the fishing effort directed at this stock. During this period, there have been significant changes in recruitment, which was good in 1983 and 1987 and poor in 1982, 1985, 1986, and 1988. Some links between recruitment anomalies and environmental parameters (surface temperatures, prevailing winds, sea level) have been identified. Variations in recruitment can be explained on the basis of fluctuations in “environmental windows" during the periods of spawning and larval drift. The success of spawning is controlled by the existence of a favourable environment during larval drift into areas with weak upwelling and abundant food.Versión del edito

A possible relation between sardine fisheries and oceanographic conditions in NW Spanish coastal waters

The NW of more often the shelf sardine in Spain is influenced by episodic upwelling which occurs between March and October. The consequent enrichment of waters is the origin of a very important fishery for the area. Eggs and larval survival is directly related to the oceanograph¡c conditions between the date of birth and recruitment. Laryal survival seems to be related essentially to weak upwelling conditions since they favour the non-dispersion of eggs (larvae) and allow growth of medium sized phytoplankters as suitable food. On the other hand, strpng upwelling causes dispersion of eggs (larvae) and favours growth of very large phytoplankton specles, mainly diatoms, that are thought to be un-suitable food for larvae. However, strong upwelling conditions are favorable for sardine adults, since the large phytoplankters growing during these upwelling events were found to be the main food supply, as shown by the study of stomach contents

The effect of environmental changes in the Galician sardine fishery

Annex 6The highest catches of the Iberian sardine stock are taken from the southern part of Galician waters (NW corner of the Iberian Peninsula) and northern Portugal. Landings are mainly composed of younger fish, which reflects the proximity of the main recruitment area to the fishery grounds. Since 1978 there has been an improvement in the knowledge of the biology and stock dynamics of sardine around the Atlantic Iberian waters. In the last decade a consecutive years with poor recruitments result in a depletion of stock below limits previously recorded. The recruitment processes seem to be driven by oceanographic (local) and climatic (global) events, this dependence on both phenomena may explain the fluctuations on the landings in the sardine fisheries in Atlantic Iberian waters. Given the dependence of the fishery in this area on the strength of the recruitment, different relationship between biotic components (spawning stock size, recruitment, landings and recruitment landings) and abiotic: climatic indices (NAO-winter, Gulf Stream and AMO) and local oceanographic coastal events (upwelling and poleward current) were analysed. In the analysis of the abiotic series in the period (1978–2005), there appears to be a shift in the general trend in 1995. In addition at the end of the nineties several consecutive years with poor recruitment result in a depletion of the stock below limits previously recorded as well as changes in the distribution area. Before the shift was observed the recruitment variability could be explain by the environmental variables, but since then the correlation is poor

´Primary productivity in winter in the Ria of Pontevedra (NW of Spain) and the changes caused by the contamination

Spatial distribution in winter of the primary productivity in the Ria of Pontevedra (NW of Spain), is shown. It is proved that industrial and urban efluents have a negative effect on photosynthesis, especially on the surface of the water, and on the Northern Coast, which is in accordance with the dynamics of the RiaOn indique la distribution spatial d'hiver de la production primaire dans la Ria de Pontevedra (NO d'Espagne). Les debuts industrielles et urbains affectent negativement la photosynthése. Cette influence est plus noté dans la surface et spécialement dans la zone Nord de la Ria

Utilização de boro em olivais de sequeiro

Nos olivais tradicionais de sequeiro de Trás-os-Montes o boro assume papel de importância similar ou mesmo superior a qualquer dos macronutriente N, P e K. Sintomas visíveis do nutriente são usuais e carências dissimuladas, detectadas em análises foliares, são também frequentes. O boro pode ser gerido a partir de aplicações de adubos sólidos ao solo, sprays foliares ou combinando ambas as estratégias

Teores de azoto, potássio e boro em folhas de oliveira após aplicação regular dos elementos ao solo e em sprays foliares

A aplicação de fertilizantes destina-se principalmente a repor as saídas de nutrientes com a exportação da fracção economicamente útil das culturas, Em culturas perenes, como o olival, a manutenção de teores foliares dos nutrientes em níveis adequados pode ser uma estratégia de fertilização racional. Neste trabalho apresentam-se resultados dos teores de azoto, potássio e boro nas folhas em função da aplicação anual dos nutrientes. Ensaios de campo com duas modalidades de azoto, três de potássio e três de boro são conduzidos em olival de sequeiro de Verdeal Transmontana em Mirandela, desde o início de 2004