Search results for " Migration"
showing 10 items of 754 documents
Behavioral responses of Atlantic cod to sea temperature changes
2015
Understanding responses of marine species to temperature variability is essential to predict impacts of future climate change in the oceans. Most ectotherms are expected to adjust their behavior to avoid extreme temperatures and minimize acute changes in body temperature. However, measuring such behavioral plasticity in the wild is challenging. Combining 4 years of telemetry-derived behavioral data on juvenile and adult (30–80 cm) Atlantic cod (Gadus morhua), and in situ ocean temperature measurements, we found a significant effect of sea temperature on cod depth use and activity level in coastal Skagerrak. During summer, cod were found in deeper waters when sea surface temperature increase…
The desert at Zait Bay, Egypt: a bird migration bottleneck of global importance
2009
The study area at Zait Bay, Egypt (c. 700 km2) is situated in the middle of the West Asian-East African migration flyway used by very large numbers of soaring migrants. At this site the corridor narrows into a bottleneck. There exist only very few bottlenecks of this magnitude in the world. Observations were performed at all hours between sunrise and sunset at 26 observation sites, situated 5 km apart. The northern part of the area under investigation (19 observation sites) was situated within the Gebel El Zeit IBA (criteria A1 and A4iv), while the southernmost part (8 observation sites) was outside. The overall evaluation has shown that 179,681 soaring birds including 122,454 storks and 36…
Rotifer vertical distribution in a strongly stratified lake: a multivariate analysis
1998
The main source of variation of rotifer species distributions in lake Arcas-2, a small karstic lake near Cuenca (Spain), was explored by means of principal components factor (PCA) and canonical correlation (CCA) analyses. PCA was performed using rotifer densities and CCA using rotifer densities plus physical and chemical parameters. Factor 1 of PCA separated summer species from winter-spring species and Factor 2 accounted for the variation in the vertical profile. Three summer species with different food habits (Polyarthra dolichoptera, Hexarthra mira and Asplanchna girodi) were grouped together at the positive end of Factor 1, while Factor 2 separated the two hypolimnetic species (Filinia …
The effect of temperature fluctuations on oxygen consumption and ammonia excretion of underyearling Lake Inari Arctic charr
1998
Underyearling Lake Inari Arctic charr Salvelinus alpinus were acclimated to 11·0) C for 3 weeks, and then one group was maintained at 11·0) C and others were exposed to 14·4) Cconst, 17·7) Cconst or a diel fluctuating temperature of 14·3° C ± 1° C (14·3° Cfluc). Routine rates of oxygen consumption and ammonia excretion were measured over 10 days before the temperature change and over 31 days following the change. Measurements were made on fish that were feeding and growing. The temperature increase produced an immediate increase in oxygen consumption. There was then a decline over the next few days, suggesting that thermal acclimation was rapid. For groups exposed to constant temperature th…
Diel vertical movements of zooplankton in lake La Cruz (Cuenca, Spain)
2000
The study of diel vertical movements of zooplankton in a small meromictic karstic lake (lake La Cruz), presenting highly stratified waters, was performed using two different methodologies: (i) samples were taken along the vertical profile and were compared at different hours in a diel cycle; (ii) some plankton traps were located at different depths, covering different periods of time, to catch organisms going upwards and downwards. The main subject of this study has been the vertical movements affecting rotifers since they were dominant in the zooplankton of this lake, but we have also included the results obtained for other zooplankton groups. The results indicate an almost general movemen…
Copepod limnocalanus macrurus mating in relation to vertical migrations and aspects of feeding rates in the Bothnian Sea (Baltic Sea)
2006
The studies of calanoid copepod Limnocalanus macrurus feeding rates and mating related to vertical migration were conducted in October 2005 in the Bothnian Sea. The monocyclic copepod Limnocalanus macrurus develops mostly to adult and larger copepodites stages in autumn and these stages were investigated. Bothnian Sea is a brackish-water basin in Baltic Sea with comparatively big depth therefore Limnocalanus macrurus which prefer to live in deep and cold water is more abundant in this Baltic Sea part. Recent observations in the Bothnian Sea showed that Limnocalanus macrurus performs diel vertical migrations and adults approve stricter tendency to stay under thermocline layer at night than c…
Overcoming the crisis : the changing profile and trajectories of Latvian migrants
2016
The work was funded by the National Research Programme [grant number 5.2.4] and the Latvian Council of Sciences [grant number 514/2012]. Taking mobility between Latvia and Western Europe as an empirical lens, this analysis explores the complex relationship between spatial disparities in earning potential and migration. The very dramatic shifts in the economic and political context against which migration from Latvia has occurred over the period 2004-2012 make it an especially apposite focus of research investigating the link between mobility and labour market circumstances. As an analytical starting point, conventional economic theory broadly explains the movement of workers from lower to h…
Introduction. The Global Old-Age Care Industry. Tapping into Care Labor Across and Within National Borders
2021
A few weeks after the first COVID-19 infections were diagnosed in Germany, NGOs and experts in the field of old-age care warned of acute bottlenecks in the provision of care for older Germans. They feared that care workers from Eastern Europe who were travelling back to their home countries might not be able to return to Germany due to the closure of borders. As a result, up to 200,000 migrant care workers could be missing after Easter. The weekly German magazine Der Spiegel quoted one NGO’s spokesperson saying: “We already had a shortage of care workers, the crisis has been here for a long time.” Another NGO’s spokesperson was particularly concerned about older people in need of care who w…
Migration, Productive Return and Human Capital: Lessons from the new Governmental Policy on Migration in Ecuador
2017
In 2008, the Government of Ecuador initiated a programme for productive return dubbed the Cucayo Fund, aimed at financing small businesses for migrants who were returning to the country. This programme has been a cornerstone in the new governmental policy on migration. In 2015, the IOM considered it an exemplary practice among the instruments enabling the economic and social reinsertion of returning migrants. In this article, based on the mining and analysis of the implementation data from the Cucayo Fund in the three provinces comprising Administrative Region No 7, we specifically examine the incidence of human capital accumulated by the migrants in the success of their ventures. Our resul…
DETERMINANTS OF EDUCATIONAL ADVANCEMENT OF RURAL AREAS IN POLAND
2017
The article is an aimed attempt at the diagnosis and evaluation of the educational level (character) of rural population in Poland perceived as educational advancement as well as of its environment (background). Growing importance of education in improving professional opportunities, changing educational aspirations and parents’ support as well as positive internal migration trends were emphasised. Rural regions are still lagging behind urban areas, though optimistic characteristics indicate receding stigmatisation and marginalisation of the Polish country with internal migration of young and educated individuals, including affluent ones (potential luxury goods buyers), to rural area…