The Barents Sea is strongly influenced by human activity: historically, involving the fishing and hunting of marine mammals. More recently, human activities also involve marine transport of goods, oil and gas, tourism, aquaculture, and bioprospecting. Fishing is believed to have the largest human impact on the fish stocks in the Barents Sea, and thereby on the functioning of the whole ecosystem. However, observed variations in both fished species and the ecosystem as a whole are also the effect
of other pressures such as climate and predation.
A reduction in fuel consumption per kg fish caught by the Norwegian fishing fleet has been observed in recent years. Purse seiners and coastal seiners have the lowest fuel consumption per kg fish caught (0.07-0.08 ltr/kg fish); whereas long-liners, small coastal vessels, and the bottom trawlers have higher fuel consumption (from 0.17-0.34 ltr/kg fish). All fleets have managed to reduce their fuel consumption in recent years.
The Barents Sea remains relatively clean with low pollution levels compared to marine areas in many industrialized parts of the world. Major sources of contaminants in the Barents Sea are natural processes, long-range transport, accidental releases from local activities, and ship fuel emissions.
The Barents Sea can become an important region for oil and gas development. Currently offshore development is limited both in the Russian and Norwegian economic zones (to the Snøhvit field north of Hammerfest in the Norwegian zone), but this may increase in the future with development of new oil- and gas fields. In Russia there are plans for the development of Stockman, a large gas-field west of Novaya Zemlya. The environmental risk of oil and gas development in the region has been evaluated several times, and is a key environmental question facing the region as well as an area of popular concern (Hiis Hauge et al., 2013) (Figure 4.4.9).
Transport of oil and other petroleum products from ports and terminals in northwest-
Russia increased over the last decade. In 2002, about 4 million tons of Russian oil was exported along the Norwegian coastline, in 2004, the volume reached almost 12 million tons, but the year after it dropped, and from 2005 to 2008 was on the levels between 9.5 and 11.5 million tons per year. In a five-ten years perspective, the total available capacity from Russian arctic oil export terminals can reach the level of 100 million tons/year (Bambulyak and Frantsen, 2009). Therefore, the risk of large accidents with oil tankers will increase in the years to come, unless considerable measures are imposed to reduce such risk.
Tourism is one of the largest and steadily growing economic sectors world-wide. Travels to the far north have increased considerable during the last 15 years, and there are currently nearly one million tourists annually visiting the Barents Region.
The high biodiversity of the oceans represents a correspondingly rich source of chemical diversity, and there is a growing scientific and commercial interest in the biotechnology potential of Arctic biodiversity. Researchers from several nations are currently engaged in research that could be characterized as bio-prospecting.
Aquaculture is growing along the coasts of northern Norway and Russia, and there are several commercial fish farms producing salmonids (salmon, trout), white fish (mainly cod) and shellfish.
Both human-induced climate change and ocean acidification may have large impacts on the Barents Sea ecosystem in the future. Accordingly, interest has increased in determining the most likely ecosystem response.
Barents Sea fish stocks undergo large variations in recruitment related to variations in environmental factors and interactions between species, including birds and marine mammals.
The ecosystem has an inherent tendency to fluctuate between: 1) periods of strong cod and herring recruitment with reduced capelin stock size; and 2) periods when herring are largely absent, cod recruitment is moderate, and the capelin stock is large (Gjøsæter, 1995).
Fisheries for pelagic stocks also strongly impact the ecosystem by intensifying these inherent fluctuations (Gjøsæter, 1995). Overfishing clearly contributed to complete collapse of the herring stock at the end of the 1960s (Dragesund et al., 1980), and may also have contributed to the capelin stock collapse in the mid-1980s. At the same time several gadoid stocks collapsed (cod, haddock and saithe) (Nakken, 1998).
As such, an important effect of fisheries for pelagic stocks in the Barents Sea is to increase the instability in the entire ecosystem. The reduced herring stock in 1983 limited its potential to rebuild following good recruitment conditions in 1983-85. Subsequent herring year classes were therefore too small to support the cod stock, and the capelin stock was more heavily preyed upon. The cod stock suffered from a food shortage; growth declined and mortality increased due to both cannibalism and fishing mortality. The result was that all three stocks were heavily reduced, and the crisis at the fish level of the ecosystem had severe effects on the higher levels of the food web, e.g. dying seals and birds, and led to economic ruin for many fishermen (Gjøsæter, 1995).
There is generally wide species diversity on the seabed. Russian researchers have identified approximately 2,700 species of benthic animals in the Barents Sea; comprising approximately 80% of the total fauna in the region. Fishermen have long reported that in some areas sponges and corals dominate the seabed. New coral reefs are continually being described along the coast of Norway where they are found mainly at depths of between 200 and 600m (Buhl-Mortensen, 2006). Some 109 species of sponge are found along the coast of Norway in the Barents Sea, but information about the geographic distribution of sponge colonies is limited.
These cold-water coral reefs, coral gardens, and sponge aggregations provide habitat for a variety of fish and invertebrates and thus represent hotspots of biodiversity and carbon cycling in the Barents Sea. Lophelia pertusa forms coral reefs, while horn corals (e.g., Paragorgia arborea, Paramuricea placomus, and Primnoa resedaeformis) may form coral forests, with colonies up to three meters high (Buhl-Mortensen, 2006).
These high-latitude habitats are dominated by large sessile fauna, many of which are K-selected, and have slow growth rates, relatively long life spans, low reproduction rates, and are important for energy transmission in the ecosystem (MacArthur and Wilson, 1967). Such species are vulnerable to bottom-trawl fisheries and other human activities such as oil and gas exploration. Because corals and sponges grow very slowly, recovery of these habitats may require from decades to centuries to recover, and in some cases may not recover at all (Fosså et al., 2002; Fosså and Kutti, 2010). As such, they are examples of Vulnerable Marine Ecosystems (VMEs). Impact or damage may lower the local biodiversity and diminish the possibility for many species to find shelter and feeding grounds (Buhl-Mortensen, 2006).
The most widespread fishing gear used in the central Barents Sea is bottom trawl, but also long line and gillnets are used in the demersal fisheries. Pelagic fisheries use purse seine and pelagic trawl. Trawl doors may cause furrows of up to 20cm deep depending on the door weight and the hardness of the sediment. Such marks are likely to last longer in sheltered areas with fine sediments. Side-scan and video recordings of a sandy/gravel bottom in the Barents Sea also showed physical disturbance from trawling, with highly visible furrows (10cm deep and 20 cm wide) and berms (10cm high) caused by the doors and smaller depressions created by the rockhopper gear (Humborstad et al., 2004; Løkkeborg, 2005).
It is estimated that between 30 and 50% of Lophelia reefs are either impacted or destroyed by trawling. Passive gear like long-lines and gillnets anchored on the bottom also impact the coral reefs, but to a considerably lower extent than trawling (Fosså et al., 2002). Norway’s Institute of Marine Research has documented the remains of sponges left behind in bottom trawl tracks. In addition to the direct physical destruction (crushing) from bottom trawling, particles are stirred from the seabed which may block the sponges’ pores; thus reducing their ability to filter food particles from the water (Buhl-Mortensen, 2006).
A comprehensive experiment conducted on the Grand Banks showed a 24 percent decrease in total biomass of megabenthic species (Prena et al., 1999). For the macrofauna, total numbers of individuals decreased by 25 percent (mainly owing to declines in polychaetes) immediately after trawling in one of the three years of the experiment (Kenchington et al., 2001). The most prominent feature of the Grand Banks study was considerable interannual variability in the mega- and macrofaunal assemblage, which indicates that the benthic community at the study site is dynamic and exhibits natural changes (Kenchington et al., 2001). Similar conclusions can be drawn from the Barents Sea experiment by Kutti et al. (2005) (Løkkeborg, 2005).
Ocean acidification (CO2 emissions)
As an inflow shelf into the Arctic Ocean the Barents Sea has a strong potential for significant uptake of CO2 from the atmosphere, and is vulnerable to the effect of increased levels of CO2 leading to ocean acidification (Orr et al., 2005; Steinacher et al., 2009; Bates and Mathis, 2009). This may be detrimental to marine organisms, and hence may affect energy transfer through food-chains (Fabry et al., 2008). Several studies have demonstrated a coupling between sea-ice melt and calcification state, implying that further freshwater addition from glacier and sea-ice melt may speed up acidification (Chierici and Fransson, 2009; Yamamoto-Kawai, 2009). The increase in atmospheric CO2 and elevated oceanic uptake of atmospheric CO2 results in decreased pH and carbonate ion concentrations; this is expected to put stress particularly on calcifying marine organisms (i.e., calanus, pteropods, and fish). Due to its present carbonate chemistry with relatively high CO2 levels, the Barents Sea is particularly vulnerable for enhanced freshening and loss of sea-ice cover, which will promote further solubility and amplification of ocean acidification. In addition to direct effects of changes in pH and carbonate ion concentrations on marine organisms and ecosystems, there also may be indirect effects on internal molecular processes within marine organisms (i.e., blood-regulation and protein synthesis). Additional effects include, potential changes in biogeochemical cycling of substances, especially nutrients and micronutrients, and their bioavailability for primary production (Breibarth et al., 2010; Ingvaldsen et al., 2013).
The Barents Sea remains relatively clean with low pollution levels compared to marine areas in many other industrialized parts of the world. Major sources of contaminants in the Barents Sea include: natural processes; long-distance transport of atmospheric deposition; accidental releases from local industrial activities; and vessel fuel emissions. Norway has recently conducted a number of baseline studies to provide essential and reliable information on levels of contamination in important commercial species in the Barents Sea and adjacent waters, e.g., concentrations of metals in muscle and liver tissues of more than 800 Northeast Arctic cod caught at 32 sites during 2009-2010 (Julshamn et al., 2013).
Reported disposal of large quantities of radioactive wastes in Arctic Seas by the former Soviet Union has prompted interest in the behavior of long-lived radionuclides in polar waters. The question has arisen as to whether radionuclide bioconcentration factors and sediment partition coefficients in the Arctic are different from those derived from studies in temperate ecosystems. Fisher et al. (1999) present concentrations in seawater and calculated in situ bioconcentration factors for 90Sr, 137Cs, and 239+240Pu (the three most important radionuclides in Arctic risk assessment models) in macroalgae, crustaceans, bivalve molluscs, sea birds, and marine mammals as well as sediment Kd values for 13 radionuclides and other elements in samples taken from the Barents and Kara Seas. Results indicated that surface water concentrations of each of the three radionuclides were very similar between the two bodies of water, indicating no evidence of locally elevated concentrations of any of these contaminants in the dissolved phase. Further, surface and deep water concentrations of 90Sr and 137Cs generally did not differ appreciably (Fisher et al., 1999).
The Barents Sea is considered as a relatively clean environment, not much affected by inputs of contaminants from human activities. The contaminant level is generally lower than in temperate areas. However, there are well-known reasons to concern. Industries on the Kola Peninsula and in eastern Finnmark, such as nickel smelters, emit a wide spectrum of pollutants. Another possible source of contamination is the increasing oil and gas exploration activity and the transportation of oil. There is a continuous increase in traffic of Russian oil, transported from the Russian Arctic through the Barents Sea. Oil exploration in the Norwegian part of the Barents Sea is strongly regulated to reduce environmental impact. Long-range transport is considered the most widespread input source of pollutants to the Barents Sea. The main contaminants of concern are persistent organic pollutants (POPs) that accumulate in the organisms in the top of the food chain.
Definition of pollution
In overall terms, pollution is defined as introduction of solids, liquids or gases into the ground, water or air, which cause or may cause damage or nuisance to the environment. Also noise and vibrations, light and radiation, and matter with a temperature significantly higher or lower than that of the surrounding may be covered by this definition. In this report the term pollution refers to elevated levels (above natural background levels for naturally occurring substances and levels above zero for man-made synthetic substances) of oil components/hydrocarbons, radioactive substances and environmentally hazardous substances. In addition, noise (see chapter 2.5.2), marine litter and ocean acidification are included.
Environmentally hazardous substances: Substances that are not readily biodegradable or are bioaccumulative (become concentrated in living organisms) and that may cause damage even in low concentrations. They are substances that are most dangerous for the environment and may also be very hazardous to health. They are categorised as ecological toxins. The main sources of releases of hazardous substances used to be industrial production processes. Today, releases from products are more important. The most dangerous hazardous substances are persistent organic compounds (POPs) such as PCBs, alkyl phenols, flame retardants and heavy metals like mercury and cadmium.
Radioactive substances emit ionising radiation. Radiological toxicity varies widely from one substance to another depending on how readily they are absorbed by living organisms, the type of radiation they emit and its intensity. Radioactive substances are unstable and decay over time. Half-life is used as a measure of how long-lived a radioactive substance is, and can vary from only a few seconds to several hundred thousand years.
Pollution caused by discharges of oil or other hydrocarbons is measured as total levels of hydrocarbons (THC), levels of polycyclic aromatic hydrocarbons (PAH), and as NPD, i.e. the sum of naphtalene, phenanthrene, and dibenzothiophene, including their C1-C3 alkylated homologues. These indicators (among others) are used to define the petrogenic or pyrogenic origin of environmental hydrocarbon pollution. In the Barents Sea, environmental PAHs may originate both from natural (e.g. coal-bearing bedrock, seafloor oil and gas seeps) and anthropogenic sources (e.g. offshore industry, coal burning, private wood-burning stoves, shipping, and scooter traffic).
Naturally occurring pollutants contribute to the contamination of the Barents Sea. These “natural pollutants include hydrocarbons, radioactive substances and heavy metals such as arsenic and nickel, which seep out of the sea-floor sediments. In order to predict the possible impact of these “natural” pollutants on ecosystems (including man) it is important to determine their background levels. It is also important to understand the level of adaptation occurring among organisms inhabiting these naturally polluted areas.
Ocean acidification is the ongoing decrease in the pH in the oceans caused by uptake of anthropogenic carbon dioxide (CO2) from the atmosphere. When carbon dioxide is absorbed by the oceans it reacts with seawater to form carbonic acid. The ocean acidification is greater and happening faster than any previous acidification process experienced in millions of years. The absorption of CO2 generally goes faster in colder waters and thus may rapidly affect the Barents Sea. Acidification will profoundly affect phytoplankton (coccolithophores), corals, molluscs, echinoderms and crustaceans, but recent research also indicates that eggs and larvae of fish may be endangered. Substantial effects on the ecosystems may be expected within a generation in many areas (see chapter 5.x.4.3)
Sources of pollution
Local sources of pollution
Oil and gas
Oil and gas activities mainly influence levels of hydrocarbons, some heavy metals and radioactive substances. Since there so far have been limited oil and gas activity in the Barents Sea, it has had little effect on the pollution situation in the area. But, oil and gas activities will probably have some effects on the area in the years to come as there are plans for increasing the activity on both Norwegian and Russian side in near future (see 2.5.2 for further details).
There are oil and gas fields in both the Russian and Norwegian part of the Barents Sea. One has to remember that even unexploited oil and gas reservoirs may represent some danger to the ecosystem due to the natural discharge of liquefied gas along the tectonic faults. According to Sevmorgeo, some faults dissect the entire sediment level and are fixed at the bottom of the sea as relatively small siphons (up to 1 m in width and a few meters deep). These siphons are sources of local and temporary anomalies in levels of heavy metals and hydrocarbons. They have been observed during the monitoring efforts near the Shtokman and Fedynsky fields as well as in the bottom waters and bottom sediments.
Industrial activities, such as mining and oil production may change the distribution of naturally occurring radionuclides in the marine environment. In particular, as a result of offshore oil production, produced water containing dissolved 226Ra and 228Ra are discharged into the sea (NRPA (2004, 2007b). Additionally, the possible use of Floating Nuclear Power Plants (FNPP) in oil and gas extraction in the Russian Arctic increases the potential risk of radioactive pollution in the region. In particular, the use of FNPP for power generation for oil and gas extraction at the Shtokman field in the Barents Sea has become an area of primary concern in relation to the presence and transport of FNPP’s and related technologies in the area, and the associated risk posed to the environment and human health. The primary groups of concern from a pollution point of view are the fission products (e.g. Cs, Sr isotopes) and transuranics (e.g. Pu, Np isotopes). Aside from risks associated with FNPP’s themselves, there is further potential for pollution arising from supporting shore based facilities designed for the purpose of refuelling, waste handling, decommissioning and other activities (NRPA, 2008b).
Maritime transport and fisheries
Shipping can negatively influence the environment through operating discharges to sea and air, illegal discharges, noise and introduction of foreign species from ballast water and hulls.
Maritime transport will continue to increase in the Barents Sea area. The opening of new oil and gas fields and less ice in the area will contribute to this. On Russian side the building of Shtokman and on Norwegian side the opening of Melkøya and Snøhvit causes enhanced activity. Many new oil ship terminals have been constructed in Russia causing the oil traffic from Northwest Russia to Europe to increase rapidly since 2002. Along the Norwegian coast “ships routeing” has been established to reduce the risk of acute oil pollution, but the increased traffic will force these routes to go further from the coast in the future. In the Barents Sea there are four offshore oil transfer points; Varandey, Peschanoozerskoe field plus two in the Kolsky gulf. All this leads to a significant increase in the risk of oil spills.
The increase in ship traffic routes, potential and planned transport of nuclear materials in and out of the region are also a matter of obvious concern. In particular, the presence and export of FNPPs in the region will affect the risk of accidents and incidents involving a release of radioactive substances to the marine environment (NRPA, 2007a, 2008b).
The fishing industry is important in the area and considered a significant source of pollution. Trawling causes direct disturbances to the environment, while fish waste and macro contamination of the sea bottom caused by old trawls; ships etc. are other important pollution problems. In Norway the destruction of coral reefs and spawning- and nursery areas for commercial fish stocks have led to implementation of restrictions on trawling near the coast and near some known coral reefs.
We do not know enough about local pollution as a result of illegal discharges from ships. In general little is known about inputs and impacts of waste to the Barents Sea area. We know that plastics waste from fisheries and shipping is a big problem in other sea areas and has documented harmful effects on many sea mammals and birds. The animals get tangled and die, or they eat the plastic and damage their intestinal systems. The extent of this problem in the Barents Sea area is unknown.
Other sources of radioactive substances
Several other local sources exist in the Barents Sea area which poses a potential threat to the radioactive contamination of the marine environment. Among these are radioactive waste containers dumped in the Barents and Kara Seas by Former Soviet Union (FSU) and the sunken submarines the Komsomolets and K-159 in the Norwegian Sea and the Barents Sea (NRPA, 2006; 2007 (RAME).|Furthermore, underwater and surface nuclear tests on Novaya Zemlya between 1955 and 1962 have resulted in localised areas of high levels of radionuclides in sediments. The main anthropogenic radioactive contaminants are 137Cs, 90Sr, 241Am and 239+240Pu.
Marine litter may affect the whole marine environment (seabed, water column and coastlines). The presence of litter may pose a risk for marine animals (e.g. seabirds) trough ingestion and entanglement. The main sources for marine litter include tourism, shipping and fishing, including abandoned and lost fishing gear. Discharges of waste from ships are the main source of litter on beaches in the area. Status for marine litter is given in chapter 126.96.36.199.
Long–range transboundary pollution
In addition to pollution from the Arctic countries themselves, the Barents Sea also receives considerable inputs of long-range transboundary pollution. Contaminants are transported into the area by winds, ocean currents, rivers and ice. The Arctic is particularly vulnerable to long-range transport of contaminants because of the dominant air and ocean currents. Transport routes and deposition of organic compounds, heavy metals and radionuclides in the Arctic may be strongly influenced by climate change.
Atmospheric transport is the most rapid route for persistent organic pollutants (POPs) such as polychlorinated biphenyls (PCBs), BFR, PFC and mercury. These substances mainly enter the Barents Sea area through long-range transport from sources in Europe, North America and Asia. Industrial areas in Russia are also an important source. According to Shevchenko V.P. (2006) an atmospheric transfer of aerosols as far as 10 000 km in 5-10 days is possible in the northern polar region. He has calculated that aerosol input represents about 10% of the present sediment formation, and elements such as Pb, Sb, Se and V reach the sea bottom via atmospheric transport.
In addition, fallout from atmospheric nuclear weapons tests (1950-1980) and the Chernobyl accident can still be found in the Arctic marine environment.
Rivers and ice
Pollutants such as PCBs, radionuclides and oil components in large Russian rivers like the Yenisey and Ob can be carried into the Kara Sea where they are incorporated into ice and transported onwards into the Barents Sea. The Norwegian rivers that transport pollution into the area are mainly contaminated with heavy metals from the smelting plant in Nikel.
Ocean currents, particularly the Norwegian coastal current, transport contaminants into the Barents Sea. This is especially noticeable for radioactive contaminants (137Cs, 239+240Pu, 241Am and 99Tc) resulting from discharges from European nuclear reprocessing facilities in the Irish Sea and English Channel and fallout from the Chernobyl Accident in 1986 in outflowing Baltic water which are then transported by ocean currents to the Barents Sea (e.g. Aure et al, 1998; NRPA, 2007; Matishov, 2001).
In recent years research has shown that a lot of arsenic as well as geochemically active forms of heavy metals enter the Barents Sea with the currents.
Secondary sources of pollution
Secondary contamination is represented by fallout of aerosol particles from ice and snow into the sea water, input of chemical components from the bottom sediments as a result of geochemical processes in the “sea bottom-water” border region and formation of new chemical compounds within the water column from simpler components. Contamination due to water exchange in the river mouth where the industrial areas/human settlements are upstream can also be considered as secondary. Secondary pollution also occurs in course of change in the redox-potential in the near-bottom waters from positive to negative and infiltration of heavy metals and other toxic substances from the pore water to near-bottom water.
Pollution from onshore and near-shore sources
In northern Norway small-scale releases from many different sources such as landfills, fish farms, contaminated sites and small enterprises may have the overall effect of raising pollution levels in near-shore waters. In many harbours where there are or have been shipyards or boat-builders’ yards, the sediments are polluted by tributyl tin (TBT) and tar. PCBs have also been found in some areas.
The main near/on-shore industry in the Norwegian part of the Barents Sea is the production field for liquefied natural gas (LNG) located in the Hammerfest area (Hammerfest LNG). This is Europe´s first and the world´s northernmost LNG establishment and became operational in 2006. Hammerfest LNG includes the subsea production field (Snøhvit, Albatross, Askeladd), a 143 km submersed pipe-line, an onshore processing plant, storage tanks and a LNG shipping harbour. LNG plants emit environmental pollutants to water and air at the extraction field, during processing and during loading and shipping. Pollutants include hydrocarbons, ammonium,VOCs, NOX, SO2, CO, CO2, heavy metals, black carbon et c. Initial production difficulties lead to exceptionally high gas flaring activities in 2007, with high black carbon and CO2 emissions. Norwegian petroleum production plants are constrained by a zero environmental impact agreement. This implies thorough monitoring of discharges to water and air and continuous implementation of reduction measures. Produced CO2 is, e.g. reintroduced in the seafloor under the well and flaring is highly restricted (Miljødirektoratet, 2010). The increased LNG shipping traffic is also a new source of pollution within the area.
Figure X.X. Statoil’s LNG plant at Hammerfest. (Photo: Harald Pettersen)
In addition to Hammerfest LNG there are several small-scale discharges from sources on the main land such as landfills, fish farms, contaminated sites and small enterprises, which may have the overall effect of raising pollution levels in near-shore waters. In many harbours where there are or have been shipyards or boat-builders’ yards, the sediments are polluted by tributyl tin (TBT) and tar. PCBs have also been found in some areas.
Elevated sediment concentrations of PAHs >3000 ng/g DW are found in the Barents Sea along the southeast coast of Svalbard (Dahle et al, 2006; Green et al, 2010). Due to their petrogenic signature, these PAHs are considered to originate from natural erosion of coal bearing bedrock. However, the larger scale environmental fate of PAH laden coal dust from closed coal mines with abandoned coal mounds is not well documented. Coal mines, closed and active, are situated along the west coast of southern Svalbard and in Ny Ålesund. Concentrations of PAHs in north-western Barents Sea surface sediments have not changed between the 1990s and 2000s, indicating a steady PAH supply. There is, however, a change in PAH composition suggesting a change in sources from exclusively petrogenic to also include pyrogenic sources (Dahle et al, 2009), indicating increased atmospheric PAH input to the Barents Sea.
In the Russian part of the Barents Sea area the local sources of pollution are considerable. An example is the municipal and industrial waste water in Murmansk which is discharged practically without any treatment. The coastal areas, and particularly the bottom sediments, are therefore not just contaminated, but represent some new compounds containing >10g/kg hydrocarbons and with altered physical properties. An aerosol transport of emissions from Monchegorsk steel plant has an active impact on the ecosystem of the coastal waters of the Kola Peninsula
The multiple Russian naval bases with nuclear submarines also constitute a big pollution problem. This includes leakage of radioactive substances from radioactive wastes stored in shore facilities (e.g. from Andreev bay), the use of support vessels to store radioactive waste (e.g. the Lepse), diesel and waste water discharge, pollution from special painting used on the ships and waste water from the communities connected to the naval bases. In the areas of tactical exercises there is a large amount of metal and, at times, highly toxic liquids that end up on the sea bottom. There is also a huge impact on the ecosystem from semi destroyed and sunken ships that often contain large amount of fuel.
Norwegian aquaculture has grown from its pioneering days in the 1970s to be a major industry (Taramger et al., 2014). Along with expansion have come a number of operational challenges related to: genetic integrity of wild stocks; parasitism; disease; and nutrient loading of the environment. It has even been suggested, that salmon farming may actually be the major threat to the viability of wild salmon populations due to facilitating the spread of diseases, escapees, environmental pollution, etc. (Liu et al., 2011). Based on evidence of the severity, geographical extent and duration and/or reversibility of the various impacts related to open sea cage salmon farming in Norwegian coastal waters, Taranger et al. (2014) report on a risk assessment the environmental impact of salmon farming considering hazards related to: 1) genetic introgression of escaped farmed salmon into wild populations; 2) impact of salmon lice (Lepeophtheirus salmonis) on wild salmonid populations; 3) potential disease transfer from farmed salmon to wild salmonid populations; and 4) local and regional impacts of nutrient loading from marine salmon farms. Primary findings were that:
- During 2010-2012, 21of the 34 populations included in assessment (62%) had moderate-to-high risk of undergoing genetic changes due to introgression of farmed salmon. However, a recent study of 20 Norwegian rivers has demonstrated that there is only a moderate correlation between the observed frequency of escapees and introgression of farmed salmon (Glover et al., 2013a); therefore, validation of the level of introgression in a higher number of native populations will be required in the future
- During 2010–2013, salmon lice infections from salmon farming were estimated at109 stations along the Norwegian coastline. Twenty-seven of these stations (25%) indicated moderate or high likelihood of mortality for wild migrating salmon smolts. For sea trout later in the season, 67 of the stations indicated moderate or high likelihood of mortality on wild sea trout
- The high frequency of viral disease outbreaks in farm-raised salmon entails extensive release of causal pathogens for certain diseases in many areas. This makes it likely that migrating wild salmon and local sea trout will be exposed to the associated causal pathogens. However, the extent and consequences of this exposure remain largely unknown
- During 2013, 2% (of the 500 stations investigated) had unacceptable organic loading in fauna and benthic sediments under fish farms. Whereas, 11% classified with high organic loading, but were still within an acceptable threshold. The remaining 87% of the farms had a moderate-to-high loading conditions. The risk of eutrophication and organic overloading in benthic communities beyond the farm production area was considered low based upon case studies and limited monitoring data (Taramger et al., 2014)
Invasive and Non-indigenous species
Non-indigenous aquatic species are of primary concern to many regulating authorities and are seen as a top anthropogenic threat to the world’s oceans. In many regions the most prominent introduction vectors are shipping, intentional introductions for aquaculture and stocking purposes — including target and non-target species. Hence, the relatively low number of non-indigenous species occurring in European Arctic waters (including the Barents Sea) may be due to the comparably lower number of ports accommodating ships during inter-oceanic voyages, and fewer aquaculture facilities (Gollasch, 2006). Nonetheless, a number of non-indigenous species — ranging from unicellular algae to vertebrates, but excluding parasites and pathogens — are reported to have established self-reproducing populations in European Arctic waters, including: Sargassum muticum/wire weed, Jap weed, strangle weed; Codium fragile-Fragile spp./green sea fingers; Bonnemaisonia hamifera/Red alga; Mya arenaria/Soft-shelled clam, soft clam, long-necked clam; Paralithodes camtschaticus/red king crab; and Chionoecetes opilio/snow crab (ICES ACOM, 2009).
The 2 non-indigenous crab species currently play a significant role in both the Barents Sea ecosystem and economy:
- Red king crabs were intentionally introduced into the Barents Sea by Russian scientists more than 40 years ago and has now become a common species in coastal areas in northeastern Norway and coastal and also covers more offshore areas in Russian waters. Along the Norwegian coast the red king crab is common west of the border between Troms and Finnmark, and eastwards at the entrance to the White Sea in Russian waters. Red king crabs are fished commercially in the Barents Sea, and fishing quotas in the two countries are decided separately (Hjelset, 2014)
- Snow crab was first recorded in 1996 at Goose Bank in the eastern region of the Barents Sea. Since then it has spread throughout the Russian zone and is now found in most of the eastern Barents Sea. Rough estimates by Russian scientist indicate that snow crab biomass is approximately ten times higher than that of red king crab, and about half the biomass of shrimp. This indicates that the snow crab is now a major component of the Barents Sea ecosystem’s food web. However, the ecology of this new inhabitant is not well understood
- Despite the potential negative effects —from accidental or intentional introductions of non-indigenous species — on the Barents Sea ecosystem, there are quite obvious positive aspects for the economic prosperity of the region. Both red king crab and snow crab Opilio have become important commercial species in the Barents Sea
- Red king crab has been exploited by both Russia and Norway since 1994, with a total catch of 8 – 10 thousand tons during some years. Predicted annual catch of red king crab in the coming years may be around 6-8 thousand tons
- During 2013, an experimental fishery for snow crabs opilio was conducted in international waters of the Barents Sea for the first time; total catch did not exceed 500 metric tons, but according to forecasts of abundance for snow crab opilio its annual catch in the coming years may be about 20-50 thousand tons. Russian authorities planned to start a small fishery for snow crab in 2014 (Hjelset, 2014)