Effects of fishery closure on perch was detected as female perch was on average 5 cm longer in closed areas compared to non-closed areas. This could be a result of larger individuals surviving as an effect of reduced fishing. No effect was detected on the reproduction rate of YOY (young of the year) perch.A zooplankton survey revealed less amounts of the most important plankton groups for YOY perch in areas with failed reproduction, though the difference was statistically insignificant.The distribution of YOY perch and YOY/adult stickleback differed completely in this study with no area where the two species are both present. It is sketchy to draw any conclusions from this data but it remains a field for further investigation.The reproduction problem is concentrated to the outer parts of the archipelago which confirms previous studies of the geographic extension..

The lake Spexhultasjön is a moderate humic mesotrophic lake that is not acidified. The fish fauna was investigated by using a standard method for sampling freshwater fish with multi mesh gill nets. The fish fauna was diverse with perch, pike, tench, common whitefish, and roach. Perch and roach dominated. There were few pikes.

This report deals with life-history variation for Eurasian perch (Perca fluviatilis L.), with special emphasis on age and size at maturity in females, in perch populations that have changed in size distribution. The collection of fish samples was made with multimesh gill nets year 2011. The perch?s length, height, weight, status of gonads has been analyzed, and by observing the opercular bone the age has been determined. In two lakes close to Umeå in northern Sweden, Fisksjön and Ängersjön, the live-history traits of perch have been studied.

Pharmaceuticals are environmental pollutants that are a major threat to aquatic ecosystems and very little is known about their ecological consequences. In this study growth, survival and behaviour (sociability, activity and boldness) of perch fry (Perca fluviatilis) were examined in order to study the possible effects of exposure to a benzodiazepine anxiolytic drug, Oxazepam, during embryonic development. The study tested following hypotheses: (1) perch growth is affected positively by exposure during embryonic development; (2) early perch survival is affected positively by exposure during embryonic development; and (3) boldness and activity increases while sociability decreases in perch fry exposed during embryonic development. Embryos of naturally spawned perch were exposed to water with two different concentrations of Oxazepam. The embryos were exposed during different parts (24-hour periods) of the embryonic development, because embryos may be more vulnerable at certain times during embryonic development and/or because the exposure at different times can produce different effects.

Pharmaceuticals are environmental pollutants that are a major threat to aquatic ecosystems and very little is known about their ecological consequences. In this study growth, survival and behaviour (sociability, activity and boldness) of perch fry (Perca fluviatilis) were examined in order to study the possible effects of exposure to a benzodiazepine anxiolytic drug, Oxazepam, during embryonic development. The study tested following hypotheses: (1) perch growth is affected positively by exposure during embryonic development; (2) early perch survival is affected positively by exposure during embryonic development; and (3) boldness and activity increases while sociability decreases in perch fry exposed during embryonic development. Embryos of naturally spawned perch were exposed to water with two different concentrations of Oxazepam. The embryos were exposed during different parts (24-hour periods) of the embryonic development, because embryos may be more vulnerable at certain times during embryonic development and/or because the exposure at different times can produce different effects.

A literature review of contaminants; cadmium, methylmercury, dioxins, and PCB, for eleven different fish species (Greenland halibut, gilt headed bream, sea bass, wolffish, hoki, ocean perch, angler, Nile perch, pangasius, red snapper and tilapia) that were selected in concurrence with the National Food Administration. The result can be used by the National Food Administration to gain further knowledge about the different fish species to be able to continue to give advice to varied risk category and the public. The gilt headed bream and sea bass were the only fishes whose values for mercury exceeded the limit of 0,5 mg/kg (EU Reg. 1881/2006). In the angler, Nile perch and pangasius the mean value of mercury didn?t exceed the limit, however in some individuals the mercury content did exceed what is allowed.

Perch (Perca fluviatilis) is a very popular fish in Sweden and it is common in Swedish waters. In some areas along the Swedish coast the perch population has decreased. It is therefore important to get a view at the health status of perch. During April, July and August of 2008, a total of 346 perches were caught in the Gump Bay in the Botnian Sea. The fish were mainly caught by net but also by rod.

This thesis aims to analyze the similarities and differences in how identity is constructed by the European Commission, the Council of Ministers and the European Parliament regarding the Polish membership and the potential Turkish membership of the European Union. The construction of identity is analyzed through a social constructivist perspective where identity is constructed by distinguishing ?us? from ?them?. The research metod used is a qualitative text analysis. The arguments of identity are taken from the Commission?s and the Council?s documents, as well as from the debates of the European Parliament.

Predation is a strong dective force on invertebrate prey. Asellus aquaticus differs in pigmentation reed and submerged vegetation habitats in lakes. Light pigmented individuals al vegetation dominated by Chara sp. while dark pigmented individuals dominate in the reeds. These differences have been hypothesized to result from background matching.

European identity is a topic constantly debated around Europe. There are many takes on whether there is a European identity and what the European identity consists of. In the European Union the Commission has worked towards developing a common European identity since the middle of the 1970?s. The development of a European identity is an important part in the commission?s quest to tie the union and its people closer together.

There are several thousands shallow bays along the Swedish east coast. Most of them are disturbed by different human activities, and undisturbed bays can be considered as quite unique. In the sheltered shallow bays water warms up more rapidly than adjacent water favoring the growth of vegetation, which in turns is beneficial to spring spawning fish species like perch and pike. It is nowadays more common that coastal habitats are inventoried to facilitate future preservation and planning. The aim of this study was to investigate the shallow bay Utanåfladen (59° 53`31.38 N 19°00`44.90 E) in the north Stockholm archipelago and evaluate its habitat value.

During the last two hundred years many wetlands and streams in Sweden have been lowered to provide land for agriculture and forestry. Some of the coastal wetlands and streams probably served as spawning sites for certain species of fish in the Baltic Sea, but the present situation is not well known. As standardized methods to monitor fish in running waters are carried out during late summer or autumn, there is a need for methods to sample spring-spawning fish in these streams.The aim of this study was to survey the lower kilometer stretch of Hammerstaån in Stockholm, to investigate the extent to which the stream is used by spring-spawning fish. Furthermore, the study aims to evaluate a new type of survey fishing gill net called strömöversiktsnät (SÖN). This was done by comparing the catch of fish by SÖN with that of fyke nets.

This thesis treats the normative power of the European Union and its affect on Macedonia. The main purpose has been to look closer with the use of the application of Ian Manners theory of normative power on the Macedonian case. The focus will be to answer the following questions: Does the European Union act as a normative power in relation to Macedonia, if so, how are these values diffused? Has there been any effect of the spreading of these values? Based on six interviews and the available material of European Union strategies for the Macedonian membership I have attempted to understand to what extent the European Union?s normative power has had an influence in Macedonia. The result of my analysis is confirmation of the European Union as a normative power in Macedonia and the understanding of the methods of application..

After the fall of the Iron Curtain the European Union was challenged partly by an institutionalized organization of the union, as well as by a socio-psychology awareness concerning the meaning of the European Union. The increase in European integration has generated a political collaboration where national understandings in identities are constantly being exposed for reconstruction. This results in a collective European identity where states are united in diversity.National identities are created when boundaries are set up in a relation to other states. In these identity constructions there are thoughts and questions raised such as who we are and who we are not. Ukraine and the European Union has, during a long time, had diversified preconceptions concerning who has been the others.

Public opinion has increasingly become a political force in the European integration process. At present, it appears that the people?s attitude towards the European integration is relatively skeptical. How can we expect that the attitude towards European integration will evolve in the future? This paper tests the extent to which diffusion theory can serve as a model to explain the development of attitudes to European integration policy in Sweden from 1999 until 2009.