Sökning: "stock abundance"
Visar resultat 1 - 5 av 10 avhandlingar innehållade orden stock abundance.
1. Fisheries biology of the edible crab (Cancer pagurus) in the Kattegat and the Skagerrak - implications for sustainable management
Sammanfattning : The European edible crab (Cancer pagurus) is exploited to a varying degree in its area of distribution. Landings in United Kingdom and Ireland may have peaked around year 2000, reaching 25 000 and 13 000 tonnes, respectively but have slightly decreased since. LÄS MER
2. Old-Growth Forests in the High Coast Region in Sweden and Active Management in Forest Set-Asides
Sammanfattning : In today´s intensively managed landscape, very few forests with old-growth characteristics and little human impact exist. One of the rare exceptions is pine forests on rocky soils, a forest type which has probably escaped extensive human use because of its low productivity. LÄS MER
3. The decline of great Arctic charr in Lake Vättern : empirical and theoretical analyses of suggested causes
Sammanfattning : Human activity is affecting species and ecosystems all over the world. In aquatic systems negative trends can be seen for many fish stocks and potential consequences of this, for ecosystem structure and functions, are of particular concern. LÄS MER
4. Functional Extinctions of Species in Ecological Networks
Sammanfattning : Current rates of extinctions are estimated to be around 1000 times higher than background rates that would occur without anthropogenic impacts. These extinction rates refer to the traditional view of extinctions, i.e. numerical extinctions. LÄS MER
5. Distribution and activity of pelagic fish - acoustic studies in the Baltic Sea
Sammanfattning : Fisheries agencies around the Baltic Sea use hydroacoustics to assess stock sizes of herring and sprat. These assessments rely on the assumption that the acoustic properties of Baltic clupeids are the same as North Sea herring. LÄS MER
