Impressive numbers of global and regional governmental and non-governmental organizations are working in the field of the marine environment and its resources. Many of these organizations operate within international legal frameworks ranging from comprehensive global conventions, such as the United Nations Convention on the Law of the Sea to regional agreements aiming at protection and development of regional seas. Characteristic for the management of these seas, both at the national and international level, is that sectoral approaches predominate. Over time, several initiatives have been taken to improve cooperation, coordination and integration to achieve greater coherence of policies and strategies between different organizations dealing with marine and maritime management, within and outside the United Nation system. However, the success has been limited. The weaknesses of international organizations depend fundamentally on problems at the national level. The international organizations are no stronger than their Contracting Parties allow them to be.

Globally, conflicts between marine nature conservation and fishery interests are common and increasing, and there is often a glaring lack of dialogue between stakeholders representing these two interests. There is a need for a stronger and enforced coordination between fishing and conservation authorities when establishing marine protected areas for conservation purposes. We propose that an appropriate instrument for such coordination is a broad ecosystem-based marine spatial planning procedure, representing neither nature conservation nor fishery. Strategic environmental assessment for plans and programmes and environmental impact assessment for projects are commonly used tools for assessing the environmental impacts of different human activities, but are seldom used for evaluating the environmental effects of capture fisheries. The diversity of fisheries and the drastic effects of some fisheries on the environment are strong arguments for introducing these procedures as valuable supplements to existing fisheries assessment and management tools and able to provide relevant environmental information for an overall marine spatial planning process. Marine protected areas for nature conservation and for protection of fisheries have different objectives. Therefore, the legal procedure when establishing marine protected areas should depend on whether they are established for nature conservation purposes or as a fisheries resource management tool. Fishing in a marine protected area for conservation purpose should be regulated according to conservation law. Also, we argue that marine protected areas for conservation purposes, in the highest protection category, should primarily be established as fully protected marine national parks and marine reserves.

This quality assessment of the Skagerrak-Kattegat is mainly based on recent results obtained within the framework ol the Swedish multidisciplinaiy research projekt 'Large'scale environmental effects and ecological processes in the Skagerrak-Kattegat'completed with relevant data from other research publications. The results show that the North Sea has a significant impact on the marine ecosystem in the Skagerrak and the northern Kattegat. Among environmental changes recently documented for some of these areas are: increased nutrient concentrations, increased occurrence of fast-growing filamentous algae in coastal areas affecting nursery and feeding conditions lor fish, declining bottom water oxygen concentrations with negative effects on benthic fauna, and sediment toxicity to inverte brates also causing physiological responses in fish. lt is concluded that, due to eutrophication and toxic substances, large-scale environmental changes and effects occur in the Skagerrak-Kattegat area.

In the past decade, marine protected areas (MPAs) have become an increasingly used tool for science-based conservation and adaptive management of marine biodiversity and related natural resources. In this review paper, we report on rather complete time-course series (55 years uninterrupted) focusing on comparison of the strong difference, in number and area, in establishing marine (56 MNRs) and terrestrial (4284 TNRs) nature reserves in Sweden versus marine (7001 MPAs) and terrestrial (132742 TPAs) protected areas globally. Sweden appears to follow the overall global time trends. The large backlog of MPAs in relation to TPAs is due to several possible reasons, such as (i) unclear marine jurisdiction, (ii) marine conservation policies and programs developed later than terrestrial, (iii) higher costs for marine conservation management, (iv) conflicts in marine conservation, especially the fishery, and (v) the general public's historically weak awareness of the status of the marine environment.Electronic supplementary materialThe online version of this article (doi:10.1007/s13280-017-0932-8) contains supplementary material, which is available to authorized users.

Globally, ecosystem-based marine spatial planning has become a useful instrument to coordinate the planning of different authorities. This, for balancing different requirements when managing marine areas and space. In the planning process, ecology is setting limits to which human activities are acceptable to the society. The use of the marine environment can be planned similarly as the land environment. We argue that there are several aspects which must be taken into consideration. Marine activities have traditionally been planned and managed in a sectoral way. Today, it has become obvious that a more holistic, multi-sectoral and coordinated approach is needed in future successful marine planning and management. The increased awareness of the importance of the oceans and seas challenges the traditional sector division and geographical limits in marine policy and calls for better coordinated and coherent marine policies.