7 Cumulative environmental effects: environmental and social impacts

The industries in and associated with the North Sea and Skagerrak can put pressure on ecosystems, and much has been done to reduce their impacts and the pressure on the environment. Nevertheless, there are still environmental problems in this area, and there is concern about the cumulative effects of all the different pressures on the marine environment. In future, new pressures may emerge, and we do not have a full overview of what their impacts may be.

Current, planned and future commercial activity in the management plan area must take into account the environmental problems that have been identified and the cumulative effects on the area.

The scientific basis for the management plan for the North Sea and Skagerrak concludes that there are substantial environmental problems in the area. They include overfishing of certain fish stocks, the decline of seabird populations, long-range transboundary pollution and the risk of acute pollution. Climate change and ocean acidification are new threats, and so far we know little about their impacts.

7.1 Summary of pressures and impacts

7.1.1 Summary by sector

Harvesting of biological production by the fisheries is the human activity that has the greatest impact on ecosystems today. The impacts of harvesting are assessed as moderate for some of the commercial fish stocks and minor for others. Bottom trawling is considered to have moderate to major impacts in areas that are trawled frequently. No estimate has been made of the proportion of the seabed affected by frequent trawling, but the impacts for the management plan area as a whole are considered to be minor. The impacts of bycatches vary from minor to moderate, depending on the species and gear type. The impacts of changes in food supplies for seabirds are assessed as moderate, but the scientific basis for the management plan points out that there are serious gaps in our knowledge in this area.

Maritime transport can put pressure on the environment through operational discharges to water and air, illegal discharges, the introduction of alien species via ballast water or attached to hulls, discharges of litter, and noise. According to the scientific basis for the management plan, no impacts of operational discharges have been demonstrated, but little is known about the long-term effects on seabirds and other marine life. There has been little investigation of the impacts of discharges from stern tube lubricants, sacrificial anodes and other unregulated sources. Operational discharges to air from maritime transport have not in themselves been found to have direct impacts. Increasing use of anti-fouling systems containing copper could become an environmental problem, even though these are less environmentally harmful than the TBT-containing systems they have replaced. Elevated copper concentrations have been found in certain harbours. Maritime transport involves a risk of collisions that may result in acute oil or chemical pollution. The impacts of such incidents on seabirds will vary from minor to major depending on the size and type of spill, its location, the time of year and physical environmental conditions.

Petroleum activities involve operational discharges to air and water, a risk of acute pollution, and other pressures such as physical disturbance of the seabed and effects of seismic surveys on fish and marine mammals. Operational discharges from petroleum activities are generally so strictly regulated that they are considered to have no or only minor impacts during normal operations. The scientific basis for the management plan concludes that they only have more local effects, and these are ranked as insignificant for the management plan area as a whole. This conclusion is based on consequence assessments of oil spill scenarios in five selected oil-producing areas of the North Sea. However, there is still some uncertainty as regards the possible long-term effects of discharges of produced water from petroleum activities. The environmental consequences of acute pollution have also been assessed on the basis of modelling of the drift and spread of oil from discharge points in the five selected areas.

7.1.2 External pressures

The state of the environment in the North Sea–Skagerrak area is also affected by activities in other parts of the world. There are inputs of nutrients and hazardous substances into coastal waters from land-based and coastal activities, and these substances are also transported into Norwegian sea areas via air and ocean currents. Nutrients have direct impacts in coastal waters and fjords, and indirect impacts on the management plan area as a whole. Hazardous substances are considered to have moderate impacts because they tend to bioaccumulate and are therefore present in marine organisms all along the food chain.

The ocean climate in the management plan area is changing as a result of greenhouse gas emissions worldwide, ocean acidification is increasing and alien species may be introduced from other sea areas. Up to 2100, it is particularly climate change and ocean acidification that are expected to have major impacts on the management plan area. Climate change and ocean acidification may reduce the resilience of ecosystems to other pressures. The future management regime will therefore have to be adapted to changes in ecosystems.

7.1.3 Cumulative environmental effects

All ecosystem components in the North Sea and Skagerrak are affected by one or several human activities. Long-term measurement series show changes over time in the North Sea and Skagerrak. Some of the changes can be directly linked to human activity, while in other cases the causal relationships are much more complex. In many of the cases where cause and effect are clearly understood, steps have been taken to reduce the impacts of a pressure. However, despite this there are still problems to be addressed.

The greatest cumulative effects are considered to be on certain fish stocks and seabird species. Threatened species and habitat types and declining populations are particularly vulnerable to any increase in cumulative effects. Habitat fragmentation and degradation is considered to be a serious threat to biodiversity today, in marine environments as elsewhere. There is particular concern about burrowing and sessile species and benthic fish species such as sandeels.

Although each source of disturbance or damage may put little pressure on the environment, their combined effects result in the cumulative effects and problems that have been identified in the management plan area. The environmental impacts of any spills and other accidents are additional to those of normal activities and releases of pollutants. In the event of a large oil spill from a blow-out or shipwreck, seabirds, marine mammals and coastal ecosystems are expected to be most seriously affected.

The impacts it is most difficult to do anything about are those of the rising concentrations of greenhouse gases in the atmosphere, which are resulting in global warming, a higher CO₂ content in seawater and ocean acidification. For many of the other pressures, it will be possible to take steps that result in good environmental status in the long term.

7.2 How environmental impacts and cumulative environmental effects are assessed

As part of the scientific basis for the management plan, six reports on environmental impacts were compiled. Five of them deal with activities in and around the North Sea and Skagerrak (petroleum activities; shipping; fisheries and aquaculture; offshore renewable energy production; land-based and coastal activities). In addition, the environmental impacts of external pressures – climate change, ocean acidification and long-range transport of pollutants – were assessed. Figure 7.1 shows how this work has been organised.

Source Climate and Pollution Agency

The assessments describe current pressures and impacts for the level of activity in 2010, and as far as possible also projected pressures and impacts in 2030. The assessments of environmental impacts are based on:

• information about the pressures in the area covered by the scientific basis for the management plan (where they act, scale);

• knowledge about the vulnerability of the ecosystem to different pressures;

• knowledge about the occurrence of species and habitat types.

A three-point scale (major – moderate – minor) was proposed and has where possible been used in assessing the impacts of different pressures. The assessments reflect the methods normally used by the administrative bodies involved when assessing the impacts of various pressures on different ecosystem components. The three-point scale was easier to use in cases where more information was available on pressures and impacts than in cases where information was more sketchy. In many cases, knowledge of the biological impacts of pressures is still inadequate. In some cases, there were already tried and tested assessment scales – for example for evaluating the impacts of fisheries on harvested stocks or the environmental consequences of oil spills. For other pressures, expert opinion and qualitative assessments have to be used. Where information on the population status of species, the range and ecological status of habitat types, or the impacts of environmental pressures is inadequate, assessments of environmental impacts are bound to be uncertain.

With such a variable knowledge base, it has been essential to ensure that the basis for the different assessments and the sources of uncertainty are clearly described. This information is available in the impact assessments for different sectors and the other background reports listed in Appendix 1.

How cumulative environmental effects are assessed

An important goal of integrated, ecosystem-based management is to consider the cumulative environmental effects of all pressures and impacts on the environment. This is difficult to do for a large and complex ecosystem. Different pressures act on different ecosystem components, and different pressures may have either synergistic or antagonistic effects on particular ecosystem components.

The pressures and impacts associated with different sectors are so different in character that it is not currently possible to arrive at exact values for cumulative effects resulting from different pressures and across a range of geographical scales. However, by using the same methodology for all the impact assessments, it has been possible to provide a systematic overview of pressures and impacts.

The impacts of different pressures from activities within and associated with the management plan area are described in Chapter 7.3, and the cumulative effects on individual ecosystem components are discussed in Chapter 7.4. This approach is in accordance with the requirement to assess cumulative environmental effects and apply the precautionary principle, as set out in the Nature Diversity Act.

7.3 Impacts of different environmental pressures

In the impact assessments, environmental pressures were grouped into categories. For each of these categories, a table in the text below summarises the results of the impact assessments for the different sectors for 2010. If a sector does not appear in a table, it is not considered to be responsible for measurable pressures or impacts. Table 7.1 provides an overview of the pressure categories and the pressures assessed for each activity. When cumulative environmental effects are assessed, this information is considered in conjunction with any environmental degradation or damage that has already been caused or that may arise in the future.

7.3.1 Biological pressures

The greatest biological pressure is the deliberate harvesting of commercial stocks. Harvesting is an intentional and managed pressure on the ecosystem, but can have environmental impacts if harvesting levels are not sustainable and the reproductive capacity of certain species is reduced. The overall conclusion of the impact assessment for the fisheries is that most fish stocks are being managed sustainably. The environmental impacts of harvesting on these species are therefore considered to be minor. However, there is a risk that harvesting of mackerel and the shrimp Pandalus borealis is not sustainable (Table 7.2), and there are still spawning stocks of cod and sandeel that are below critical levels, even though harvesting is now considered to be sustainable. The sandeel stocks on the Viking Bank and around the West Bank and Outer Shoal were over-exploited for many years. Harvesting now follows precautionary advice from the International Council for the Exploration of the Sea (ICES), and no catches have been taken in this area since 2004 because of uncertainty about stock status. Sandeel biomass is still low in some of the other areas of sandeel habitat. The environmental impacts of the current sandeel fisheries are assessed as minor to moderate. The mackerel spawning grounds in the southwestern part of the management plan area are important for the stock. In the management plan area, the mackerel stock is above the precautionary level, but the lack of a coastal state agreement combined with large increases in the Icelandic and Faeroese quotas means that the overall mackerel harvest is considerably larger than the level recommended by ICES. However, studies by Norway, Iceland and the Faeroe Islands suggest that the stock is still in good condition.

Fisheries primarily affect the target species, but may also have impacts on other fish species, seabirds and marine mammals that are taken as bycatches. Harvesting fish can also have indirect impacts on seabirds by changing the availability of food supplies. The impacts of these types of biological disturbance are assessed as moderate, but it should be noted that there is a lack of information and that the assessments are therefore uncertain.

The introduction of alien species could potentially have major impacts, at ecosystem level as well as species level. In the management plan area, the problems are mainly related to shipping and the transport of species with ballast water and as fouling on ships’ hulls. The impact assessment for shipping concludes that the probability of an invasive species becoming established is small, but that species that do become established could have major environmental impacts.

Biological pressure exerted by the fisheries up to 2030 will depend partly on the EU’s new fisheries policy. The development of gear technology will be an important factor in reducing bycatches. International rules for ballast water management are now being put in place, and will help to reduce the probability of introductions of alien species.

7.3.2 Hazardous substances still cause for concern in the North Sea and Skagerrak

One of Norway’s environmental targets is for releases and use of substances that pose a serious threat to health or the environment to be continuously reduced with a view to eliminating them by the year 2020. In the longer term, the aim is to reduce concentrations of the most hazardous chemicals in the environment towards background values for naturally occurring substances and close to zero concentrations for man-made synthetic substances (white paper Working together towards a non-toxic environment and a safer future – Norway’s chemicals policy (Report No. 14 (2006–2007) to the Storting)).

Inputs of hazardous substances to the environment come from many different sources and affect all parts of ecosystems. Levels of such substances that are high enough to give cause for concern are being found in fish, seabirds and marine mammals, which are all groups that are particularly vulnerable because they are high up in food chains. Hazardous substances hardly ever cause acute poisoning, but there is a risk of delayed injury and chronic effects, such as a reduction of species’ reproductive capacity or survival rates. There is therefore concern about their impacts on marine organisms and on ecosystems as a whole. Elevated levels of contaminants in seafood are also a threat to food safety (see Chapter 3.2.2). Ensuring that seafood is safe by monitoring levels of contaminants and taking steps to reduce these levels is important both for consumers and for the fisheries industry.

Source EnvironmentWeb

Shipping, petroleum activities, industry and other land-based and coastal commercial activities, and also long-range transboundary pollution transported by winds and ocean currents, all result in inputs of hazardous substances to the North Sea and Skagerrak. Because these substances accumulate along food chains, the impacts of both long-range inputs and inputs from land-based and coastal activities are assessed as moderate for seabirds, marine mammals, fish, and seafood safety. Operational discharges from shipping and petroleum activities are assessed separately as having minor environmental impacts (Table 7.4). However, all pollution, even in small amounts, adds to the cumulative environmental effects on the management plan area. Given the intrinsic properties of persistent, bioaccumulative and toxic substances, and on the basis of the precautionary principle, the environmental authorities and actors in the various sectors are seeking to eliminate releases of these substances or reduce them to a minimum.

We know that there are illegal releases of oil and litter from ships, but there is little information on their size and frequency. The impacts of spills vary depending on where and when they happen. The risk of adverse impacts is higher if a spill occurs at a time when organisms are more sensitive to the effects of hazardous substances, for example if it affects fetal or early stages of development.

Pollution from petroleum activities reduced

Ordinary petroleum activities, and planned and permitted use and releases of chemicals during these activities, are assessed as having only minor environmental impacts. Considerable volumes of produced water are discharged after treatment, but the negative impacts are restricted to the immediate vicinity of the discharge point, and are only expected within a radius of a few hundred metres. There is still uncertainty about the long-term impacts of discharging treated produced water, including how this contributes to cumulative environmental effects. The Research Council of Norway has published conclusions from 10 years’ research, pointing out that although no population-level impacts were identified, the possibility that there will be impacts at population and ecosystem level cannot be excluded (see Box 7.2).

A great deal of progress has been made towards eliminating the use and discharges of hazardous chemicals added during petroleum drilling and production activities. In line with the zero-discharge targets for the industry (Box 7.1), the quantities of the most hazardous added chemicals used and discharged on the Norwegian continental shelf have been declining (Figure 7.2). The zero-discharge target is considered to have been achieved for added hazardous chemicals. Discharges of substances on the Government’s priority list from the offshore petroleum industry constitute only a small proportion of Norway’s total releases of these substances, and never more than 4 % of the total releases of a specific substance in Norway. Efforts to reduce the use and discharges of these substances are continuing. However, for safety and technical reasons it will still be necessary to use a certain quantity of these substances, and some discharges to the sea will continue in the years ahead.

Discharges of PAHs and oil

Polyaromatic hydrocarbons (PAHs) are natural components of coal and oil and are also formed during the combustion of fossil fuels and wood. Atmospheric inputs are the largest source of PAHs in the management plan area. Monitoring of air and precipitation shows no decrease in inputs since 2008.

Produced water released in connection with petroleum activities is also a major source of PAHs in the management plan area. These releases have not been substantially reduced over the past 10 years. Produced water spreads and is diluted in the water column, and impacts on living organisms are presumed to be restricted to an area within a radius of 5–10 km from the platforms. The impacts on the management plan area as a whole are assessed as minor.

There are also inputs of PAHs from land and with ocean currents, and PAHs are leached from sediments, but the size of inputs from these sources is uncertain. There are no data for operational releases of PAHs and oil from shipping. The quantities released from land-based activities and from petroleum activities are shown in Table 7.3. The highest levels of PAHs are measured in the deep sedimentation areas in the Skagerrak. According to the scientific basis for the management plan, this may have impacts on benthic communities in the area.

In the management plan area, operational discharges from petroleum activities with produced water are the largest source of inputs of oil. In a normal year, these inputs are larger than the combined quantity in spills from both shipping and petroleum activities. Releases of oil and naturally occurring hazardous substances with produced water have been reduced, but not by as much as the industry’s own goal for progress towards the zero-discharge targets. Unless further measures are introduced, oil discharges are expected to continue to rise for several years as the volume of produced water increases.

There is little data on operational discharges of oil from shipping, but estimates of oil in bilge water, based on distance sailed and maximum permitted discharges, indicate that the total quantity released by shipping in all Norway’s sea areas was of the order of 0.9 tonnes oil in 2006. This is considerably less than the quantities from petroleum activities and land-based sources.

Long-range transport of pollutants still cause for concern in Norway

Despite considerable cuts in emissions in recent years, hazardous substances are still being released to land and sea by a range of human activities. The most important transport routes for hazardous substances entering the North Sea–Skagerrak area are deposition from the atmosphere, inputs with ocean currents and inputs from land-based activities. Mercury and PCBs, for example, are found everywhere in the environment. These pollutants mainly enter the area with ocean currents and atmospheric transport (Figure 7.3). Inputs from land are also an important source of PCBs in the Skagerrak. These substances are present in marine organisms, and the environmental impacts are assessed as moderate. Measurements at the Birkenes observatory in Southern Norway show no decline in concentrations of mercury or PCBs in air, whereas there has been a downward trend in the concentration of mercury in precipitation in the last eight years. Total deposition of mercury in Norway is estimated at 2.5 tonnes per year. Most of this originates from releases in other countries, mainly from the combustion of coal, natural sources and re-emission and remobilisation of mercury. Norway has already introduced a range of measures to reduce its releases of mercury, including a general ban on mercury in consumer products. The high levels of mercury in cod demonstrate how important it is to put in place a global legally binding instrument on mercury in order to reduce inputs of mercury to the management plan area from sources outside Norway.

Source Marine Pollution Monitoring Programme 2010. Tilførsler og miljøtilstand i Nordsjøen (North Sea: inputs and environmental status), Climate and Pollution Agency. TA-2810/2011

As new knowledge is acquired, the target of halting releases of hazardous substances by 2020 is being applied to an increasing number of substances. Although the REACH Regulation (the EU/EEA regulatory framework for the registration, evaluation, authorisation and restriction of chemicals) now provides for better control of chemicals that are on the European market, we still lack knowledge about many substances. Moreover, new chemicals and products that may contain hazardous substances are constantly being produced. To minimise environmental damage, it is important to identify new hazardous substances as early as possible, before any serious health and environmental effects arise.

Radioactive substances

Most radioactive pollution in the management plan area originates from long-range transport. The most important sources of radioactive pollution in the North Sea and Skagerrak today are the remaining fallout from nuclear testing in the 1950s and 1960s, releases from reprocessing plants for spent nuclear fuel in the UK and France, and inflow of water from the Baltic Sea containing radioactive substances originating from the 1986 Chernobyl accident. Releases from petroleum activities are a source of naturally occurring low-level radioactive substances.

Releases from nuclear activities have dropped since the 1970s and 1980s, as a result of a combination of international cooperation, national regulation and improvements in treatment technology and waste management. The only exception is releases of tritium from the nuclear power industry, for which no treatment options are available. Releases of the radioactive substance technetium-99 from the Sellafield processing plant in the UK were halted in 2007, after persistent pressure from the Norwegian and Irish authorities, when the plant changed over to waste storage on land. This has resulted in a decline in technetium concentrations in the water column and in marine organisms throughout the North Sea.

The petroleum industry releases naturally occurring low-level radioactive substances with produced water. The content of radioactive substances in produced water depends on geological conditions and therefore varies from one area to another. Two installations on the Troll field are the most important sources. According to the zero-discharge goals, discharges of naturally occurring radioactive substances are to be gradually reduced so that the concentrations in the environment are close to the natural background levels by 2020. The lack of treatment technology has meant that releases have remained more or less at the same level in recent years.

Radioactive substances accumulate to different degrees in marine organisms and the food chain. For the management plan area generally, no ecological impacts are expected from the current levels of radioactivity, but this conclusion is based on limited knowledge. Nor is it expected that consumption of seafood will result in doses of radioactivity exceeding the limit values for human consumption. There is a pressing need for further investigation of the uptake, accumulation and possible impacts of radioactive pollution of the marine environment.

Projections for 2030

Since long-range transport accounts for a large proportion of the inputs of hazardous substances to the management plan area, future trends will depend strongly on developments in the international regulation of their release. Over the next 20 years, it is likely that inputs and levels of already regulated substances will decline, but inputs of some unregulated and new substances will rise until steps are taken to regulate them. An important element of uncertainty is what effects climate change will have on inputs, metabolism and uptake of hazardous substances. It may weaken the effect of international regulation; for example, hazardous substances stored in sediments may be mobilised, making the impacts on marine organisms more severe.

7.3.3 Impacts of acute pollution

The scientific basis includes analyses of various scenarios for accidents that may result in spills of oil, chemicals or radioactive waste. The type of spill and when and where it occurs play a major role in determining its potential environmental impacts. The level of uncertainty in assessments of environmental risk is relatively high, both because of gaps in our knowledge and because only a limited selection of scenarios has been analysed for each sector.

Table 7.5 summarises the assessments of the environmental impacts of the spills that have been analysed. The results are based on the Expert Group’s assessment, using the same three-point scale (minor–moderate–major) for the impacts of all pressures. These assessments should be considered in conjunction with the discussion of consequence assessments for acute pollution from petroleum activities (Chapter 6.2.3), which are more detailed and use methodology for estimating the risk of environmental consequences on the basis of pre-defined categories for population mortality and recovery time.

Projections for 2030

No significant changes in the probability of accidents that may result in spills are expected in the period up to 2030. The activity level in the petroleum industry is expected to remain fairly stable. Maritime safety measures should be able to compensate for the increase in the volume of maritime transport. Nevertheless, there is a great deal of uncertainty about future trends in environmental risk, mainly because our knowledge about the future distribution, state and vulnerability of species and habitats is limited. Changes in the location of commercial activities will also influence the level of environmental risk.

Source Climate and Pollution Agency

7.3.4 Impacts of nutrients and organic matter

Eutrophication in coastal waters and fjords can be caused by runoff from agricultural areas, inputs from industry and municipal waste water treatment, or discharges of nutrients from fish farming. In addition, nutrients are transported from the southern part of the North Sea and Baltic Sea to the Norwegian coast with ocean currents. In accordance with its international obligations, Norway has over the past 20–30 years implemented a range of measures to reduce Norwegian discharges of nutrients. National inputs of nutrients to the Skagerrak coast have been reduced since 1990. Other countries around the North Sea have also taken action to reduce discharges, and this has benefited Norway as well. However, along the Skagerrak coast nutrient inputs from land are still influencing the eutrophication status of fjords and inner coastal waters. In these areas, further measures are needed to achieve the target of good chemical and ecological status by 2021. Along the coast of Western Norway, there has been a rise in anthropogenic inputs of nutrients, largely as a result of an increase in discharges from the aquaculture industry (Figure 7.4). Calculations for two fjords (Hardangerfjorden in Hordaland and Boknafjorden in Rogaland) indicate that these discharges are not so large that they have a significant bearing on eutrophication status at regional level. Measurements of nutrients in both fjords suggest that levels are low enough that in most cases, water quality can be characterised as «very good» according to the Climate and Pollution Agency’s criteria for water quality. However, knowledge of environmental status along the coast of Western Norway is still inadequate.

In the outer zone of coastal waters and the open sea, the direct impact of nutrients and organic matter is minor, and the state of these waters is considered to be very good (Table 7.6). In the areas closest to the coast, the impacts of nutrient inputs can include sediment deposition in sugar kelp forests and in soft-bottom areas in fjords. This can result in habitat degradation in nursery areas for fish and in poorer food availability for seabirds, and thus have indirect impacts in the management plan area.

Projections for 2030

Over the next 20 years, climate change may result in higher inputs of nutrients because of an increase in precipitation and more flooding. Interactions between a rise in temperature and nutrients are presumed to have had impacts on sugar kelp (see Chapter 3.3.3). As climate change continues, more effects of this kind are expected. More precipitation in the form of rain in winter may increase runoff and erosion from agricultural areas, resulting in higher inputs of nutrients and particulate matter to river systems and from there to coastal waters.

7.3.5 Marine litter

Marine litter is considered to be a global problem and one that is growing in scale, largely because the amounts removed from the world’s oceans are so small. Most activities in or associated with the management plan area contribute to the problem, even though the disposal of waste at sea is banned by both national and international law, and clean seas are in the best interests of both industries and individuals. Under Norway’s Pollution Control Act, there is a general ban on disposing of waste in such a way that it causes littering, which applies both on land and at sea.

Textbox 7.3 Marine litter and injury to the fauna

Marine litter is a threat to the marine environment and can cause considerable harm to animal life in the sea:

• Internal effects: If animals confuse litter with food and ingest it, this can result in the uptake of hazardous substances from plastics, suffocation, or damage to the stomach and gut; litter may also block the respiratory system or oesophagus and prevent normal digestion.

• External effects: if animals become entangled in nets or other objects, they may suffocate, drown, die of hunger because they are unable to hunt or feed, be physically injured, with possible complications such as infections, or their growth may be hampered.

• Ghost fishing: lost or dumped fishing gear can continue to catch fish and other animals for long periods.

• Marine litter can put further pressure on species that are already in difficulty, such as auks and other threatened bird species.

• Marine litter may be one of several factors that in combination cause serious cumulative environmental effects.

Source Morten Ekker

The IMO International Convention for the Prevention of Pollution from Ships (MARPOL) prohibits all discharges of waste from ships. Illegal discharges from ships – and perhaps to an even greater extent, illegal discharges from ships outside the North Sea – are sources of marine litter, which can drift for long distances. However, most marine litter originates from land. Waste that is dumped illegally or carelessly near beaches and rivers can be swept into the water, for example during spring floods. Industrial waste and landfill waste can be transported by wind and surface runoff to coastal and marine waters. Particulate matter from road traffic (including asphalt and rubber particles) is also transported by runoff and stormwater. Long-range transport of marine litter from other areas is believed to account for a considerable proportion of the total quantity in the management plan area. The large rivers that drain into the southern part of the North Sea also contribute to the problem.

End-of-life and discarded leisure craft may become a serious environmental problem in the future. Calculations show that far more boats are dumped illegally than the number delivered to approved waste facilities. Leisure craft contain a range of environmentally harmful components that can pose a considerable risk of pollution. In addition, dumping boats illegally means that the materials and energy resources they contain are not properly used. The number of leisure craft is expected to rise considerably in the future, and the environmental problems will increase if end-of-life craft are not dealt with in an environmentally sound way.

Lost fishing gear, both commercial and non-commercial, is one important type of marine litter. Some lost gear ends up as beach litter, but a large proportion is believed to remain in the sea. Lost nets and traps can continue to catch fish and other animals long after they have been lost, a problem known as ghost fishing. There have been no comprehensive surveys of the scale of ghost fishing in the management plan area. From time to time, marine litter is caught in trawls, or fishing vessels retrieve marine litter in other ways. At present, there is little or no incentive to ensure that litter is collected and brought ashore by fishing or other vessels. Facilities for delivering litter that has been retrieved from the sea vary widely from one port to another.

Every year, considerable numbers of seabirds, marine mammals and fish are injured or killed by marine litter because they ingest it or come into contact with it in other ways (see Box 7.3). Table 7.7 gives an overview of the impacts of marine litter. In addition, litter can have negative economic and social impacts such as the cost of clean-up operations, damage to boats, loss of fishing gear and reduction of the amenity value of outdoor recreation areas. The coastline adjacent to the management plan area is intensively used for outdoor recreation and important for people’s well-being. Litter along beaches is an aesthetic problem and can hinder people’s use of the area. It is estimated that about 15 % of all marine litter is washed up on land, while about 15 % remains afloat in the sea and as much as 70 % eventually sinks to the seabed. However, there have been few studies to verify these figures.

Textbox 7.4 Beach clean-up and retrieving marine litter

Many people are concerned about the problem of marine litter in Norway. Litter is visually intrusive and reduces the quality of the coastline for outdoor recreation. Many volunteers, associations and organisations are involved in voluntary beach clean-up campaigns that remove large quantities of litter from selected areas. An annual beach clean-up day is organised throughout the country by the voluntary organisation Hold Norge rent (Keep Norway Clean), which coordinates efforts in different geographical areas. In addition, the Norwegian Nature Inspectorate and the county governors organise systematic efforts to clear litter from protected areas and public beaches. The intermunicipal outdoor recreation boards and other organisations are also involved in beach clean-up, monitoring of litter and information work. The Directorate of Fisheries conducts an annual retrieval programme that removes substantial amounts of lost gear and other fisheries-related litter from the sea. The programmes cover waters from Møre og Romsdal and northwards.

Source Intermunicipal outdoor recreation board for the Oslofjord

In general, knowledge of the scale of the marine litter problem is inadequate; for instance, little is known about the relative importance of international and national sources. In the scientific basis for the management plan, the impacts of marine litter from each of the relevant sectors are assessed as minor, with the exception of long-range transport of litter, which is assessed as having moderate impacts on seabirds. This conclusion is based on findings of considerable quantities of plastics in the stomachs of fulmars, and the fact that we have not achieved OSPAR’s ecological quality objective for the quantity of plastics in the stomachs of dead seabirds (see Table 7.7).

The overall conclusion is that marine litter is a substantial environmental problem in the management plan area and that further measures are needed to learn more about the scale of the problem, to reduce the quantities of marine litter entering the environment, and to remove as much as possible of the litter that is already present.

7.3.6 Physical pressures

The following types of pressures on the seabed were assessed during the impact assessments: occupation of areas, deposition of material, sealing of the seabed, sediment deposition, and bottom trawling. There is normally no dredging or dumping of dredged material in the management plan area. Installations on the seabed gradually become overgrown with marine organisms and their foundations may function as artificial reefs. There has been little investigation of their impacts. Table 7.8 provides an overview of the impacts of physical loss and damage.

Large parts of the management plan area are influenced by activities with impacts on the seabed (Figure 7.7). Bottom trawling is the most widespread activity, and its impacts are assessed as varying from moderate to major in areas that that are frequently trawled. There has been a great deal of bottom trawling in the North Sea and Skagerrak for over 100 years. This has impacts on large soft-bottom areas in relatively shallow waters and particularly along the sloping sides of the Norwegian Trench. Trawling can damage or destroy important habitats and alter the structure of benthic communities. The effects of bottom trawling are greatest the first few times an area is trawled. With repeated trawling, species that are not resilient to the activity are expected to disappear gradually. The impacts of the removal and destruction of molluscs and sessile organisms persist for a long time precisely because these organisms grow very slowly. However, benthic communities that are resilient to trawling will become established in areas that are trawled repeatedly, and will be fairly stable as long as trawling continues.

Source Directorate for Nature Management, Norwegian Petroleum Directorate and Directorate of Fisheries.

According to the impact assessment for the petroleum industry, the impacts of physical loss and damage to the seabed are minor and limited to small areas. Discharges of drill cuttings from oil and gas activities affect only a small proportion of the continental shelf. The total contaminated area around installations on the Norwegian part of the shelf in the North Sea amounts to about 90 km². The total area around installations in the North Sea where there are impacts on the benthic fauna is estimated at about 10 km². This area is largely affected by previous discharges of oil-contaminated drill cuttings, as shown by elevated concentrations of hydrocarbons and changes in the species composition of the sediment fauna. However, laboratory experiments have shown that discharges of drill cuttings with water-based drilling fluids can also have impacts on the benthic fauna, although this is limited to about 250 metres of the installations. Less is known about the impacts of drill cuttings on vulnerable benthic communities and fish species that live in and on the sediments, such as sandeels.

A number of other activities also occupy or disturb areas of the seabed, but on a smaller scale. Offshore wind power development could result in both habitat loss and habitat gain. However, wind power development would not be expected to have substantial negative impacts on benthic communities in any of the areas assessed in the strategic impact assessment.

Impacts on particularly valuable and vulnerable areas

Bottom trawling takes place in a number of particularly valuable and vulnerable areas – the Karmøyfeltet and Siragrunnen bank areas, the Skagerrak transect, the Outer Oslofjord, and «sandeel habitat south» in the southernmost part of the management plan area (see Figure 3.15). Any activities that occupy parts of these areas could reduce the amount of suitable habitat for sandeels, which are a key species in the ecosystem.

There are now strict restrictions on bottom trawling in Norway’s territorial waters. The fishing industry is likely to make increasing use of gear types that have less impact on the seabed than those in use today.

7.3.7 Impacts of noise

In recent years, underwater noise and its impacts have received growing attention both in Norway and internationally. Many marine organisms use sound as their primary form of communication, whether to find a mate, search for food, avoid predators or for navigation. Activities that generate underwater noise can affect these functions. Sources of underwater noise may generate either impulse noise (blasting, pile-driving, seismic surveys, sonar) or continuous low-frequency noise (ship propellers, wind turbines, cables, drilling). Water carries sound well, and sound travels four times as fast in water as in air. Because sound is transmitted so efficiently under water, the geographical area influenced by sound pollution can be very large.

Both marine mammals and fish are influenced by noise. Different species respond differently, and some life cycle stages are more sensitive than others. Fish, for example, are most vulnerable during spawning and spawning migrations. Noise is now believed to be a greater problem for marine mammals than was previously thought. Responses such as strong avoidance, changes in communication patterns and a sudden halt in feeding can occur even at low noise levels.

Table 7.9 provides an overview of the impacts of noise.

None of the sectors report major impacts from the noise generated by their activities. Direct impacts are assessed as local only, but behavioural changes as a result of scare effects of noise are believed to occur over longer distances. Noise has impacts on both marine mammals and fish. Larvae near sources of sound can be injured. Little is known about the effects of low-frequency noise on communication between marine mammals. Because a general increase in human activity is expected in the management plan area in the years ahead, underwater noise levels are also expected to increase.

Knowledge of the cumulative effects of noise pollution in the North Sea and Skagerrak is limited.

7.3.8 Global emissions of CO₂ and other greenhouse gases

Climate change caused by global greenhouse gas emissions has impacts on the marine environment. CO₂ emissions also result in ocean acidification. Both climate change and ocean acidification may result in large-scale changes in marine ecosystems. Table 7.10 gives an overview of the impacts of climate change and ocean acidification in the period up to 2100.

Climate change

The climate in the North Sea–Skagerrak area is changing. In the IPCC’s Fourth Assessment Report, published in 2007, most of the global temperature rise in the past 50 years is attributed to anthropogenic emissions. Because greenhouse gases have global impacts, the impacts of local emissions on the management plan area have not been assessed. On the other hand, the impacts of global warming were treated as a very important issue in the impact assessments. A variety of observed changes in the distribution of fish, plankton and benthic organisms, and also regime shifts, can be linked with climate change, although it is so far difficult to determine how much of the observed climate change in the management plan area is anthropogenic.

In future, anthropogenic climate change will probably outweigh natural fluctuations. In that case, changes in sea temperature, stratification, ocean circulation and current patterns in particular may affect the entire management plan area in varying degrees.

The causal relationships behind the anthropogenic changes are expected to become clearer, and climate change is likely to have far-reaching impacts on plankton, benthic organisms, fish, seabirds and marine mammals in the management plan area. For example, new species from further south may become established here, while more northerly species are displaced northwards. One possible effect of such changes is mismatches in time and space between prey species and the predators that feed on them, with effects along the entire food chain.

Climate change may also have impacts on pollution status by altering pollution levels, the spread and inputs of hazardous substances and the risks they pose. However, it is difficult to predict how great these effects and their significance will be. In the worst case, levels of a number of hazardous substances, both old and new, may rise. Such changes have already been observed for some hazardous substances in the Arctic. Climate change may also affect the toxicity of hazardous substances, the extent to which they accumulate in food chains and how vulnerable organisms are to these substances. Temperature changes may also affect inputs, transport and effects of nutrients. Higher precipitation may increase runoff and leach nutrients from land more rapidly, and result in remobilisation of nutrients from the environment. There are complex interactions behind such effects, and our knowledge of these issues is inadequate at present. It is difficult to predict either trends or impacts precisely and reliably. Climate change may also increase vulnerability to other pressures.

Ocean acidification

Measurements show that globally, the average pH of ocean surface water has dropped by about 0.1 pH units. During the present century, pH is expected to drop more and more rapidly. This will also result in changes in saturation levels of calcium minerals, which are vital «building blocks» for many marine organisms. No impacts of ocean acidification have as yet been demonstrated in the management plan area. However, the expected future changes in pH entail a risk of major impacts on individual species – both directly as a result of lower pH and indirectly as a result of changes in saturation levels of calcium minerals. This could in turn result in major changes in food supplies for other marine species. In addition, it is uncertain whether a lower pH may have other impacts by affecting nutrient cycles and the bioavailability of micronutrients and hazardous substances.

7.4 Cumulative environmental effects on specific ecosystem components

7.4.1 Cumulative environmental effects on phyto- and zooplankton

State

In the sea, as on land, plant growth (primary production) is the basis for all other biological production. Changes in primary production or the conditions for primary production will have impacts on all higher trophic levels in marine food chains. Many of the factors that affect the phytoplankton are also important for the production, species composition and distribution of the zooplankton. Changes in the zooplankton biomass available can affect the entire food chain.

In the past 20 years, the species composition of the phyto- and zooplankton in the management plan area has changed, partly as a result of rising sea temperature.

Causes and impacts

Shipping, petroleum activities, fisheries and long-range pollution have little impact on phytoplankton production in the North Sea and Skagerrak, nor is acute pollution expected to have measurable impacts.

Inputs of nutrients and organic matter from land-based and coastal activities may have major impacts on some coastal ecosystems, and this could have indirect impacts on the management plan area.

There are wide variations between seasons and between years in the species composition and biomass of phytoplankton. Important natural factors that influence the phytoplankton include nutrients, light, temperature, salinity, mixing of the water masses, grazing and sedimentation.

Climate change could influence several of these factors and thus result in changes that propagate upwards in food chains. We are already seeing changes in the quantity and composition of the plankton and their production cycle, which are largely attributed to climate change.

Projections

Towards the year 2100, continued ocean acidification and climate change, rising sea temperatures and increasing runoff of nutrients and organic matter from land may have major impacts on the distribution of various plankton species. This could in turn have far-reaching effects on all trophic levels in the food chain.

Global cuts in CO₂ emissions will be an important factor in the future, as will international cooperation under the EU directive on national emission ceilings for certain atmospheric pollutants and the Gothenburg Protocol (which restricts emissions of gases that contribute to acidification and eutrophication).

Despite reductions in releases of phosphorus and nitrogen both in Norway and internationally, certain coastal waters and fjords with shallow sills are still at risk of eutrophication, with excessive production of phytoplankton (high primary production). Changes in coastal ecosystems may be intensified by climate change, and would have indirect impacts on the management plan area. Integrated management in line with the Water Framework Directive will be an important management instrument in future, both in Norway and in the EU.

7.4.2 Cumulative environmental effects on benthic communities and habitats

State

The species composition of benthic communities is an important indicator of environmental quality.

Monitoring of coastal waters shows that the state of hard- and soft-bottom benthic communities in the outer zone of coastal waters is good and, and benthic communities in the Outer Oslofjord are showing a positive trend, whereas the kelp forests closest to the coast are showing a negative trend. However, our knowledge of habitat types and benthic communities in the management plan area is limited. This complicates assessments of the cumulative environmental effects on the benthic fauna and benthic communities, including assessments for particularly valuable and vulnerable areas.

Causes and impacts

Data and analyses from monitoring in the North Sea and Skagerrak indicate that there are several reasons for the changes in benthic communities. Eutrophication and sediment deposition have a marked influence on the benthic fauna and benthic communities near the coast. Elsewhere, inputs of nutrients and hazardous substances are considered to have only minor impacts. Fisheries, particularly bottom trawling, put considerable pressure on benthic communities in parts of the management plan area.

Oil and gas activities affect benthic communities and species, but to a limited extent. Discharges of drill cuttings from exploration and production drilling and other mechanical disturbance of the seabed have only local impacts. The impact of anti-fouling systems has been greatly reduced through new measures implemented by IMO.

Oil spills are not generally expected to have major impacts on benthic communities, but there may be local impacts. The potential consequences depend on the distance from a spill to shallow coastal waters, and whether there is a possibility of direct contamination of the seabed (for example if a ship is grounded). Accidents involving releases of radioactive material could have long-lasting impacts on benthic communities.

Habitat fragmentation and degradation is considered to be a serious threat to biodiversity today, in marine environments as elsewhere. There is particular concern about burrowing and sessile organisms and fish that are associated with sediment, such as sandeels. Such species are often dependent on very specific bottom conditions, and are therefore vulnerable to pressures that change the quality of the substrate or influence ocean currents. Fishing with bottom gear, fixed installations, mooring systems and pipelines laid on the seabed can all cause such changes. There is little documentation of quantities of marine litter on the seabed, but this can be a considerable problem for the benthic fauna and other animals that live near the seabed.

One of the world’s largest known inshore cold-water coral reef complexes, the Tisler reef, is in Ytre Hvaler national park. Restrictions on bottom trawling have been introduced to protect the coral habitats here. It is considered important to obtain more information on the state and occurrence of vulnerable, habitat-forming benthic organisms such as corals and sponges in the management plan area.

Projections

Projections indicate that direct and indirect pressures and impacts related to climate change and ocean acidification will have a strong influence in the period up to 2030 and 2100, and that there may be major impacts on benthic communities. Sugar kelp forests and coral reefs are two of the habitat types that are vulnerable to temperature changes. Kelp forests are important for biodiversity, for example as nursery areas for fish larvae and feeding areas for several species of seabirds. Coral reefs are complex habitats that also support high levels of biodiversity. Both corals and other calcifying organisms will be vulnerable to increasing acidification.

The situation for benthic communities by 2030 will depend on activity levels and the management measures that are implemented. In areas where there are particularly valuable and vulnerable benthic communities, developments will depend on the cumulative environmental effects and on the requirements that apply to activities in and around such areas. Fisheries management measures could be an important factor for benthic communities that are currently trawled frequently.

7.4.3 Cumulative environmental effects on fish stocks

State

In the past 10 years, there has been concern about poor recruitment to several of the most important fish stocks in the North Sea. Several marine fish species are classified as threatened on the Norwegian Red List. Inputs of hazardous substances have resulted in worryingly high levels of some substances in certain fish species.

Causes and impacts

The state of a particular stock is determined by the sum of a whole range of pressures and impacts. In addition to heavy fishing pressure, the background reports for this white paper have identified environmental changes, especially changes in temperature and in zooplankton communities, as important factors.

If a fish stock is weakened and vulnerable, even relatively minor negative pressures and impacts may have disproportionately strong effects.

High levels of certain hazardous substances have been measured in a few fish species from the North Sea and Skagerrak (see Chapters 3.2.2 and 7.3.2). We know too little about the effects of long-term exposure and the combined effects of exposure to mixtures of different pollutants, and about new substances. Physical conditions such as temperature, salinity stratification, suspended particulate matter, food supplies and ocean acidification are very important for the early life stages of fish. Climate change may also influence survival in early life stages, growth and sexual maturity. Many fish species are able to move away from areas where conditions are suboptimal, and a northward shift in the distribution of several gadid species has already been observed. However, species such as sandeels that are closely associated with particular habitats cannot adapt in this way, and are therefore vulnerable to climate change and other more direct pressures within their distribution range.

Projections

The projections indicate that climate change and ocean acidification will be the factors that have most impact on fish in the years ahead. Climate change has already resulted in more frequent observations of commercially important species such as anchovy, pilchard, John dory, rudderfish, surmullet and Atlantic pomfret in the North Sea. Anchovy and pilchard in particular, both of which are pelagic schooling species, may become important for the fishing industry and for the North Sea–Skagerrak ecosystem. At the same time, a warmer climate may displace species that are currently common in the North Sea away from the area.

Several of the fish stocks in the management plan area are managed jointly by Norway and the EU, and they cooperate on the management of a number of other species. Successful fisheries management in the future will depend on agreement between Norway and the EU on joint management measures, and on their implementation in practice. It will be crucially important for the EU to introduce a ban on discards.

7.4.4 Cumulative environmental effects on seabirds

State

A number of seabird populations in the North Sea and Skagerrak are declining because of climate change and other effects of human activity that have resulted in changes in the availability of prey. This applies to both breeding and wintering populations, and to both coastal and pelagic seabirds (those that feed out at sea). Several species are listed as threatened on Norway’s Red List for 2010.

Causes and impacts

The scientific basis distinguishes between direct pressures on seabirds, such as acute pollution, hazardous substances and disturbance of breeding sites, and indirect pressures that result in changes in their food supplies. In the case of indirect pressures, there are complex interactions involving human activities that cause changes resulting in poorer conditions for seabirds.

Levels of hazardous substances are highest in species at higher trophic levels. Along the Norwegian coast, gulls and great skuas have been found to contain the highest levels of persistent organic pollutants. Large gulls, which also visit landfills and urban areas, are likely to be more vulnerable to contamination with hazardous substances through their food than purely fish-eating species or pelagic feeders. Hazardous substances can have greater impacts on reproduction and survival during periods when little food is available than when there are abundant food supplies. Discharges of nutrients from agriculture, municipal waste water treatment, aquaculture and industry near the coast can have indirect impacts on coastal seabirds, since they can result in eutrophication, which in turn has impacts on ecosystem components such as kelp forests and reduces food supplies for seabirds.

Seabirds are particularly vulnerable to marine litter, because they can mistake fragments of plastic for food and ingest them.

Textbox 7.6 Particles of plastic in seabird stomachs

Fulmars forage exclusively at sea, feeding on floating dead fish and fish waste from fishing vessels as well as live fish. They often confuse floating fragments of plastic with food and ingest them. These fragments may be of a shape or size that makes it difficult for them to pass through the digestive system. The effects depend on how where the blockage occurs. Fragments stuck high in the oesophagus can choke a bird, while further down or in the stomach they may reduce food intake or the ability to ingest food. In the longer term, this can damage the digestive system or kill the bird. Persistent organic pollutants can bind to the surface of small plastic particles, adding to the accumulation of such substances in marine food chains.

In a study of beached seabirds found at Lista near the southern tip of Norway, 98 % of the birds were found to have plastic particles in their stomachs. On average, each stomach contained 46 plastic particles, with a total weight of 0.33 grams. This is equivalent to a large dinner plateful of litter in a human stomach.

Source Jan van Fraeneker

There is a great deal of pressure on the coastline adjoining the management plan area; it is heavily used by leisure craft and for outdoor activities such as camping and bathing, which can disturb seabirds during the breeding season and reduce breeding success, particularly in coastal species. Disturbance during the breeding season can make the adult birds leave their nests, which may then be robbed by other birds, particularly crows and gulls.

Seabirds are highly vulnerable to oil spills. Important factors in addition to the size of a spill, are its timing and location in relation to the seabird distribution. There is a high level of uncertainty in estimates of the consequences of spills. A small spill may kill more birds than a major spill if it coincides in time and space with large numbers of seabirds. After the grounding of the Full City in the Outer Oslofjord in 2009, it was estimated that 2000–2500 seabirds died. Of these, 1500–2000 were common eider. However, this mortality had little effect at population level.

Hunting of a few seabird species is permitted. In the management plan area, it is largely common eider and cormorant that are hunted, including about 9000 eider a year along the Skagerrak coast. Seabird populations that are registered as declining are not hunted. Hunting pressure has been gradually reduced over many years in Nordic waters, and this has greatly reduced its importance as a threat to seabird populations. There are no indications that the current level of harvesting has any significant effect on populations in the Norwegian part of the North Sea and Skagerrak.

Seabirds are also taken as accidental bycatches, particularly in gill nets. Too little is known about the scale of these bycatches at present. This issue is attracting considerable attention internationally, and in autumn 2012, the EU published an action plan for reducing incidental catches of seabirds.

Seabird numbers in the North Sea are largely a result of high primary and secondary production of phyto- and zooplankton, and large stocks of small pelagic fish species such as herring, sprat and sandeels. The food preferences of seabirds include a wide range of prey species, and preferences may vary considerably through the year, between years and between regions. In the breeding season, a number of seabird species forage up to about 100 km out to sea from their colonies. It is the younger year classes of herring that are particularly important seabird prey, especially in the open sea, while sandeels and sprat are suitable throughout their life cycle because of their limited size. Sprat and sandeels are especially important for a range of coastal seabird populations. Herring and sprat are important food species for common guillemots, razorbills and kittiwakes in the North Sea for much of the year, but gadids such as poor cod, Norway pout and young year classes of saithe also make up a substantial part of the diet of wintering auks. During the breeding season, sandeels are a particularly important food species for gulls, including kittiwakes, and auks. There is no fishery for coastal stocks of sandeels.

Marine ecosystems are complex, and in most cases the decline of a seabird population is probably due to several factors. Developing an understanding of these complex interactions is a challenging task. The importance of indirect impacts of climate change on seabird populations varies geographically and between species. As the temperature of seawater rises, organisms such as the copepod Calanus finmarchicus, herring and mackerel respond by altering their distribution patterns. Seabird populations that have already been negatively affected by changes in food supplies are more vulnerable to direct pressures.

A reduction in the availability of prey species has been identified as one of the reasons for the decline in several seabird populations in recent years. The fisheries can have indirect impacts on seabirds through changes in the species composition and quantities of potential prey species. The report Action plan for seabirds in Western-Nordic areas, published by the Nordic Council of Ministers in 2010, contains a review and assessment of pressures and impacts on seabirds in the Northeast Atlantic, based on information from national and international experts. The report highlights three pressures that are important for many seabird species in large parts of the study area. These are climate change/rising sea temperatures, competition with fisheries and oil pollution. The report identifies food shortages caused by competition between seabirds and fisheries as an important cause of the problems many seabird populations are experiencing in areas where fisheries and seabirds compete for the same species. However, seabirds and fisheries do not necessarily compete for the same fish resources at the same time and in the same place. There is often a time lag, and competition may be indirect. We still need more knowledge to understand the mechanisms involved and quantify the relationships. A working group of seabird experts and marine scientists has been established to investigate the links between the decline in many seabird populations and their food supplies, and suggest measures to improve food availability for seabirds.

Projections

Large-scale climate change will have far-reaching impacts on the species composition, numbers and temporal and spatial distribution of seabirds in the North Sea and Skagerrak. Signs of change have already been documented for both seabirds and fish in the region. In the breeding season, seabirds have a limited radius of action when foraging because they have to return to their eggs or young, and they are therefore particularly sensitive to changes in the availability of prey species, regardless of the reason behind such changes.

If wind farms are established near the coast or offshore in the management plan area, there could be conflicts with seabirds in the areas Frøyagrunnene and Olderveggen, because these overlap with feeding areas for red-listed species such as puffin, common guillemot, kittiwake, common tern and black guillemot in the breeding season. Wind farms could also cause problems for migratory species. There is some uncertainty about the impacts of wind farms in the other areas proposed for wind power developments. The main impacts for seabirds are expected to be direct mortality as a result of collisions with turbines, degradation and fragmentation of habitats, and disturbance (particularly during the construction period) that may cause birds to avoid or move away from the area.

Threats to seabird populations are not delimited by national borders, and this complicates the pattern of threats facing seabirds, which also vary through the year. Pressures outside the management plan area may thus have strong effects on populations that breed within it.

7.4.5 Cumulative environmental effects on marine mammals

State

Whale populations in the North Sea and Skagerrak are stable. Protection has had a positive impact on seal populations, but the common seal is still listed as vulnerable in the 2010 Norwegian Red List.

Causes and impacts

Pressures known to affect marine mammals in the North Sea and Skagerrak are hazardous substances, marine litter, and noise from sonar and propellers. Marine mammals are taken as bycatches, primarily in gill nets. Since they are top predators, marine mammals often have high tissue loads of hazardous substances. The impacts of long-range transboundary pollution and inputs from land-based and coastal activities on marine mammals are therefore assessed as up to moderate. Knowledge from other sea areas indicates that natural mortality, infections and lower fertility can be linked to hazardous substances. The spill scenarios that have been assessed show that oil spills from petroleum activities could have up to moderate consequences for seals (grey seals).

Projections

In addition to the long-term impacts of pollution by hazardous substances, the situation for marine mammals may deteriorate in future as a result of climate change, and as an indirect result of ocean acidification. However, there is considerable uncertainty attached to these assessments.

7.4.6 Cumulative environmental effects on coastal waters and the shore zone

Many of the people who live along the Skagerrak and North Sea coast have close ties with the sea and coastal zone, and use these areas for recreation and outdoor activities, commercial fisheries and recreational fishing. At the same time, human activity is having marked environmental impacts in the area. Hazardous pollutants have been and still are a major problem in many coastal and fjord areas. They may originate from industrial emissions, releases from urban areas or remobilisation of earlier releases, for example pollutants leached from sediments in ports and harbours where they have accumulated. The Norwegian Food Safety Authority has therefore issued a general advisory to the whole population against the consumption of liver from private catches of fish taken inside the baseline. In addition, there are advisories against the consumption of fish and/or shellfish from specific areas of a number of harbours and fjords.

Marine litter drifts in the Norwegian coastal current. As a result of wind, current and geographical conditions, it is more likely to accumulate in some localities along the coast than others, and there is an exchange of litter between open waters and the shore zone. The future impacts of marine litter are assessed as moderate.

Other activities that influence the environment in coastal waters and the shore zone are outdoor recreation and tourism, and generally the presence of people – all positive for the human population, but with negative impacts on seabirds, which are easily disturbed during vulnerable periods of the breeding season. The American mink, an alien species in Norway, has spread to many islands and coastal areas, and takes birds’ eggs during the breeding season. Lobsters are locally threatened by trapping, and there is heavy fishing pressure on coastal cod. The shore zone is particularly vulnerable to brackish-water invasive alien species that are spread by shipping in harbour areas. Low temperatures have previously limited the spread of a number of introduced species in Scandinavian waters, but warmer seawater may weaken this barrier to the spread of both algae and animals.

During normal operations, petroleum activities and shipping are not expected to have environmental impacts on the shore zone. The same applies to the fisheries. However, acute oil pollution in coastal waters could have serious negative impacts on the shore zone. Higher concentrations of nutrients and organic matter could have direct impacts on kelp forests and seaweed communities, depending on the topography and current conditions. The impacts on the management plan area in the future are assessed as moderate. In addition to warmer water as a result of climate change, higher inputs of nutrients and sediment deposition have been identified as probable reasons why there is little re-establishment of sugar kelp forests along the Skagerrak coast of Norway. This situation is assessed as having moderate impacts on fish-eating seabirds that feed in kelp forests. Changes in species composition and habitats in the shore zone can influence biological production, erosion and the deposition of material in this zone.

If wind farms are established in coastal waters and the shore zone in the future, their impacts are likely to vary from one locality to another.

7.5 Costs of environmental degradation

There is a considerable body of knowledge about the state of the environment in the North Sea and Skagerrak. There is also a good deal of information about the ecosystem services supplied by Norwegian sea areas, although there are many gaps in our knowledge. However, we know very little about the loss of benefits (in other words, the costs) to society associated with the degradation of some marine ecosystems and ecosystem services.

Ecosystem services are the benefits – goods and services – that people obtain from ecosystems. The potential for value creation and earnings in sectors such as fisheries, aquaculture and travel and tourism in future will be closely linked to the state of the environment. Opportunities for value creation based on genetic resources and the use of marine resources in pharmaceutics, the chemical industry and biotechnology will also be influenced by changes in the state of the environment and the quality of the ecosystem services it provides.

In addition to these well known and recognised ecosystem services, there are many others that are less obvious, including processes such as water purification and waste treatment, maintenance of ecosystem stability and climate regulation (see Box 7.7). Most ecosystem services are public goods. They are not traded in markets and therefore have no market price. Thus, the cost of damage to such services does not appear in company budgets or ordinary accounts, at any rate not in the short term. This increases the risk of their degradation, which can undermine the basis for future prosperity. One of the main purposes of the management plan is to coordinate different interests and weigh up their importance so as to ensure that ecosystem services that are not traded in markets are also managed sustainably, so that their economic value and ecological importance are maintained.

In the case of fish and shellfish, environmental degradation means that we cannot harvest as much as would be possible if the state of the environment was improved. Analyses indicate that environmental degradation costs the Norwegian fisheries sector substantial sums every year. The loss of the sugar kelp forests can result in considerable reductions in catches of both commercial and non-commercial species.

Blooms of toxic algae and oil spills can kill fish in fish farms. The seafood industry is dependent on a good international reputation, which is not necessarily linked directly to the actual state of the environment. Any negative incidents can jeopardise the industry’s reputation and have adverse effects on sales and earnings. The costs are difficult to predict.

It is also difficult to estimate the value of genetic resources and resources that can be used by the biotechnology industry, because these are option values – values related to their possible future use.

As described in Chapter 4, there is substantial value creation and employment in the travel and tourism industry in the North Sea and Skagerrak counties. Much of the activity is related to the sea and coastal areas, but it is nevertheless difficult to assess the extent to which poorer environmental status results in a loss of production value and income.

One negative environmental trend in recent years has been the loss of sugar kelp forests in the North Sea and Skagerrak. As well as providing a habitat for many marine animals, sugar kelp acts as a sink for large quantities of carbon. Calculations based on a CO₂ price of NOK 320 per tonne show that the area of kelp forest that has been lost today corresponds to a reduction in greenhouse gas fixation valued at about NOK 1 470 million (see Box 7.8). In addition, there is no sedimentation of dead kelp material where kelp forests have been lost, and the cost of this is estimated at a further NOK 24–64 million per year. Such calculations are very sensitive to the carbon price that is used.

Losses such as a reduction in fish production, the number of recreation days or the capacity for carbon fixation are annual losses that are repeated every year as long as the degraded state of the ecosystem persists and its capacity to provide ecosystem services is reduced. If ecosystem status gradually improves, the costs of environmental degradation will be gradually reduced until good ecosystem status is achieved. If ecosystem status deteriorates further, the annual losses may increase. These matters are difficult to assess at present, but it is nevertheless of interest to examine the importance of good environmental status and ecosystem services for value creation, since this will have implications for decision-making processes.