9 research outputs found
Impact des relations intraspécifiques et interspécifiques sur l'abondance des populations
National audienc
Modélisation de la dynamique de populations piscicoles exploitées intégrant la variabilité individuelle de croissance : application aux corégones (Coregonus lavaretus) du lac d'Annecy
DiplĂŽme : Dr. d'Universit
Le phénomÚne de Lee chez les corégones du lac d'Annecy
National audienc
Modification de la rĂ©partition en taille des corĂ©gones par la pĂȘche et apparition du phĂ©nomĂšne de Lee
National audienc
A size-and age-based simulation model for evaluating management strategies of a dual exploitation of whitefish in lake Annecy
International audienc
Analysis of the fluctuations in whitefish (Coregonus lavaretus) abundance in Lake Geneva
International audienc
Elements pour la prise en compte des populations piscicoles dans le fonctionnement trophique du LĂ©man
National audienc
Impacts of climate warming on the long-term dynamics of key fish species in 24 European lakes
Fish play a key role in the trophic dynamics of lakes. With climate warming, complex changes in fish assemblage structure may be expected owing to direct effects of temperature and indirect effects operating through eutrophication, water level changes, stratification and salinisation. We reviewed published and new long-term (10â100 years) fish data series from 24 European lakes (area: 0.04â5,648 km2; mean depth: 1â177 m; a northâsouth gradient from Sweden to Spain). Along with an annual temperature increase of about 0.15â0.3°C per decade profound changes have occurred in either fish assemblage composition, body size and/or age structure during recent decades and a shift towards higher dominance of eurythermal species. These shifts have occurred despite a reduction in nutrient loading in many of the lakes that should have benefited the larger-sized individuals and the fish species typically inhabiting cold-water, low-nutrient lakes. The cold-stenothermic Arctic charr has been particularly affected and its abundance has decreased in the majority of the lakes where its presence was recorded. The harvest of cool-stenothermal brown trout has decreased substantially in two southern lakes. Vendace, whitefish and smelt show a different response depending on lake depth and latitude. Perch has apparently been stimulated in the north, with stronger year classes in warm years, but its abundance has declined in the southern Lake Maggiore, Italy. Where introduced, roach seems to take advantage of the higher temperature after years of low population densities. Eurythermal species such as common bream, pikeâperch and/or shad are apparently on the increase in several of the lakes. The response of fish to the warming has been surprisingly strong and fast in recent decades, making them ideal sentinels for detecting and documenting climate-induced modifications of freshwater ecosystems