Cannibalism can have major influence on fish population dynamics. A prerequisite for cannibalism is that the cannibal and the potential victim meet, and besides density effects, the encounter rate between cannibals and their victims is therefore also largely dependent on habitat use and habitat heterogeneity. In this study I quantified and compared the potential for cannibalism in stream-dwelling European grayling populations in three rivers in Jämtland by means of habitat classifications. I also analyzed population dynamic consequences of varying the potential for cannibalism in terms of intensity, using a physiological structured population model. Findings based on habitat characteristics were that the potential for cannibalism is in general not favourable in these types of streams.

This thesis aimed to investigate how a rising sea level would affect the livable area of the island Fongafale, Tuvalu. Through the IPCC stabilization scenarios it was examined which areas of the island that would be affected by flooding. The local population?s perceptions of the effects of climate change were studied to see how the consequences of a world-wide problem such as global warming affect people's lives. The paper clarified the Tuvaluans place in the discussion of climate refugees, explained IPCC's work and described the results of previous studies concerning people in Fongafales perceptions and concerns about climate-related changes.

It is hard to find streaming waters where humans haven?t affected the fish populations or the running water it self. In many streams the fish populations are over harvested and this results in a lack of older and larger fish. This is also the situation for many populations of Grayling (Thymallus spp.). To be able to develop management plans and to perform actions that improve the situation for the grayling, it is therefore crucial to know what natural, by humans unaffected populations look like.