High Coast / Kvarken Archipelago

Fishing remains a major pressure on several species within the site and also leads to associated food web impacts when overfishing is allowed to significantly impact trophic interactions within the ecosystem (HELCOM, 2010; 2018). Commercial fisheries exist for Baltic herring, whitefish and salmon (States Parties of Finland and Sweden, 2006; Planning the Bothnian Sea, 2012), which are subject to ICES stock advice (ICES 2013a, ICES 2013b, ICES 2013c; 2019) and today have quotas enforced for some species. However other target species include sea trout, pike and pikeperch, and most importantly perch, some of which have not historically fallen under regulations stipulating total allowable catches (HELCOM 2010). With the exception of herring and whitefish, many of the fished species are trophic level four top predators in the local ecosystem, meaning that they are fewer in number but have a proportionally larger effect on the ecosystem per individual. The Baltic herring is an important endemic species for the Baltic whose spawning-stock biomass (SSB) of most pelagic stocks has decreased over the course of the past twenty years, largely due to overfishing of the western stock (ICES, 2019). There are several important Baltic herring spawning grounds within the site, some of which overlap with the fishing grounds. Nearly all of the Baltic herring catches, 96.5 per cent, are taken by vessels under the Finnish flag. The fishing is almost exclusively done by mid-water and bottom trawls with the most intense period of Baltic herring fisheries between July and September each year (Planning the Bothnian Sea 2012). The European eel is a critically endangered species that has undergone a dramatic decline in the past 30 years, with less than 5% is left of the stock (WWF, 2017) due largely to activities at sea, including fishing, but some land based activities, such as damming of migration routes in rivers, are also a significant source of mortality (HELCOM, 2018). The endemic sea-spawning grayling (Thymallus thymallus), regionally probably now extinct aside from a smal number of isolated cases, but present further north is also another notable absence from the local ecosystem within the site, due to pressure from fishing (IUCN Consultation, 2020).  Local fisheries are affected by decreasing fish resources, but also by conflict of interest with seals and certain sea birds (Svels et al. 2019). Most Baltic Sea fish communities today are dominated by small-sized fish, suggesting that the fishable biomass could be considerably larger (HELCOM, 2018).  Intensive Commercial fisheries has led to strained stocks, with bottom trawling causing extensive damage to the marine environment, mainly in the form of withdrawals of species, including by-catch, physical damage to the bottom environment from abrasion, and increased turbidity from disturbed sediments. Underwater noise and the introduction of organic materials are also among the consequences from fishing (Swedish Agency for Marine and Water Management, 2018). Moreover, most fisheries are currently not under quota and as such are not regulated by any international body. The risk of this threat is high, although dependent on the species, based on its possible likelihood and potentially major consequences, for example decreases in large predatory fishes, such as pike and perch may disrupt the functioning of the ecosystem of the archipelago, especially in the shallow bays like flads.

Water pollution by hazardous substances remains a threat within the site and is assessed as being disturbed by hazardous substances by HELCOM. Hazardous substances are having a marked effect on the wildlife, species composition and diversity all over the Baltic. The combined effects of the substances are to a large extent unknown. but include persistence and associated bioaccumulation, and toxic effects. Hazardous substances can be man-made, such as most of the chemical compounds termed ‘Persistent Organic Pollutants’ (‘POPs’) or occur naturally, such as heavy metals. Hazardous substances reach the site through normal water exchange with the southern Baltic atmospheric deposition, river water (especially nikel and zinc), harbors, marinas and shipping lanes, as well as re-release of accumulated substances by dredging and disposal of dredged material. (IUCN, 2006, HELCOM, 2010, 2014). 
In the Swedish marine spatial planning the cumulative effects in the Northern Bothnian Sea and Norra Kvarken consists mostly of pollutants in sediment (synthetics approx. 20%, heavy metals approx. 29%) and phosphorous (approx. 27%), and a small part from nitrogen (approx. 7%) that is caused by several sectors, earlier emissions and other sources of pollution. Oxygen-free bottoms also account for a part of the effect (approx. 12%) (Swedish Agency for Marine and Water Management, 2018). Overall, as with any marine area the exchange and interaction with the environment outside the site is very high and cannot be regulated at site level. However, bans on mercury, dioxins, lead and other measures across the Baltic have taken place through international cooperation such as the Helsinki Convention. The overall risk of this threat is moderate to major, however is likely to be decreasing.

Eutrophication is triggered by excessive amounts of nutrients washed into the sea. The nutrients come from farmlands and forestry areas, homes and gardens, cars, cities and industries as well as aquaculture farms, particularly in the High Coast World Heritage area, although such aquaculture will be scaled down over the course of 2020 (IUCN Consultation, 2020). In the sea, the nutrients first foster the production of planktonic algae forming algal blooms, as well as short lived high yield filamentous algae species. This increased production of organic matter often has secondary and drastic negative consequences: the water becomes murkier and less transparent, fast growing, short lived species smother habitat forming perennials, the sedimentation of organic material to the sea floor increases, decomposition of organic matter increases and oxygen is consumed, thus depleting the bottom waters of oxygen.
Benthic communities such as meadows of submerged aquatic vegetation are deprived of light, and benthic invertebrate communities and fish are affected by oxygen depletion, ultimately suffocating.
However, possibly the most important effect of stratification in terms of eutrophication: hindering or preventing ventilation and oxygenation of the bottom waters and sediments by vertical mixing of the water, a situation that often leads to oxygen depletion. Furthermore, hypoxia and anoxia worsen the situation by affecting nutrient transformation processes, such as nitrification and denitrification, as well as the capacity of the sediments to bind phosphorus. In the absence of oxygen, reduced sediments release significant quantities of phosphorus to the overlying water. Climate change also risks increasing the nutrients carried into the sea via rivers and runoff as the precipitation increases (IUCN World Heritage Evaluation Report May 2006, HELCOM, 2010, Planning the Bothnian Sea 2012), which may be worsened further through nutrient loading in rivers such as the nearby River Kyrönjoki and clear-cutting forestry and associated flood regime alterations (IUCN Consultation, 2020). Dredging activities can also compound eutrophication by re-releasing nutrients perviously trapped in the seabed into the water column (IUCN Consultation, 2020).
According to the draft for the new status assessment in the outer parts of Kvarken Archipelago, the sea is in good status with regards to eutrophication, but decreasing. In other assessments, the entire Bothnian Bay is eutrophied. Even though nutrient inputs have been reduced substantially, their accumulation in the seabed over long time and the long retention time of water in the Baltic Sea, it will take several decades before the full effects can be measured in the environment. Of concern for the Baltic Sea is the wide and increasing distribution of areas with poor oxygen conditions in the deep water (HELCOM, 2018).
This is in essence a threat that originates outside the site and of which the site is only a small part. The management does not have the capacity or resources to address this threat, only a change in local behavior and international agreements can help alleviate the process (there is no way of reversing it). Any dredging should be strictly regulated and on a permission basis, however, this will cause tension with the stakeholders.
The risk of this threat is very high, given it's widespread occurance, and major consequences and increasing trend.

Macroscopic litter on the shores of the site causes visual intrusion and impacts on the scenic value of the area. The macroscopic marine litter in the site originates from fishing, shipping, leisure boating, tourism, coastal urban areas and rivers. Surveys done in the Baltic, concentrated on medium-sized or large particles, count up to 700–1200 particles, per 100 metres of coastal strip (HELCOM 2007d) and even though the Kvarken/High coast is amongst the less polluted areas the litter accumulates over years (it is for the most part plastic) and the long shoreline means that there is a lot of available beach for the litter to strand on.
Not all marine litter is visible to the human eye. Microscopic particles from various sources, e.g., degradation of plastic waste, disturb food webs by mimicking food particles, attaching to organisms’ feeding appendices and causing famine to passive filter-feeders. Some hazardous substances adsorb onto the litter particles and may cause enhanced accumulation of hazardous substances in the food web. Studies in Swedish waters have shown that the amounts range from several hundred to a hundred thousand microscopic pieces in a cubic meter of seawater (Noren 2007, Noren et al. 2009). For unknown reasons, the largest micro-litter problem was found in the Gulf of Bothnia, bordering the site. (HELCOM 2010). 
Increasing evidence on how the widespread use of plastic material is affecting the sea has resulted in marine litter being identified as one of the priority areas for work in HELCOM (2018).
The management has potential to reverse the effect of the threat (with regards to macro plastics). Cleaning efforts aiming at most heavily used areas would already help alleviate the visual intrusion.
The risk of this threat is high, with high likelihood and moderate but increasing consequences.

Dredging operations (both large and small scale) and the disposal of dredged material reintroduce sediment- bound TBT and other POPs to the marine environment. (IUCN World Heritage Evaluation Report May 2006). Developmental pressures include dredging of shallow areas and continual dredging of boat channels creates some disturbance (UNEP-WCMC 2011). Due to land rise dredging is very common in the area, especially on a small scale. Small scale operations, while under regulations e.g. on dumping of the dredged materials, do not need permission from any authority and are not followed up upon however must inform the authorities. The companies doing the work also need no certification, and illegal dumping of the materials straight into the sea is common. Due to the nature of the areas that need dredging (shallow, enclosed bays in the process of rising out of the sea) this practice is more common in Kvarken then in the High Coast. Such dredging may directly affect the geological values for which the site is inscribed, such as glolakes and flads. Moreover, the effect of the recirculated nutrients can have major implications for the surrounding ecosystem as they may contain toxic elements. Currently management has no legal way of regulating the small scale dredging and any such regulation of the stakeholders rights to dredge will also create serious tension between management and stakeholders. As such, addressing this threat requires short and long term impact assessments on dredging activities, which specifically consider the OUV of the site.

These seashore properties have considerable monetary and non-monetary value to a large number of people in both areas (IUCN World Heritage Evaluation Report May 2006). A rough average of the number of secondary dwellings to permanently inhabited homes in the region is 1/1 to 0.5/1 (Planning the Bothnian Sea 2012). Building of new cottages requires permission from the governing body (depending on country) and the rules are quite strict, however there is increasing pressure in the Swedish component to relax planning regulations, risking more construction along the High Coast along with the dredging associated with their construction.

Introduction of NIS (Non-indigenous species) occurs unintentionally by marine and inland shipping (ballast water and ship hulls) and intentionally for improving fisheries and for use in aquaculture. Non-indigenous species may destabilize existing ecological relationships and in the worst cases may have serious consequences on the local food web (Oguz and Gilbert 2007). Although some superior competitors and predators, for example, the American mink (Neovison vison) (UNEP-WCMC 2011), three species of the polychaete Marenzelleria and the round goby (Neogobius melanostomus), are now present in the site, there has not yet been any wide-scale economic or ecological impact following the invasion of a non- indigenous species (HELCOM, 2010). Due to the nature of the area (salinity, temperature, etc) as well as the low diversity, the region has several unexploited or shareable niches, meaning that not all NIS end up competing with or ousting already established species. However, the American mink can have a very adverse effect on the marine bird population breeding in the area as well as the introduced Raccoon Dog (Nyctereutes Procyonoides) (IUCN Consultation, 2020) and muskrats (Ondatra sibethicus) (Ilvessalo-Lax et al., 2018). Measures are being taken to diminish the negative impact. 
This threat carries variable risk, dependent on the species concerned, and required specific management accordingly. However, as with any marine area the exchange and interaction with the environment outside the site is very high and cannot be directly regulated by eg. enclosures. There is very little to no possibility for the management of the site to respond to this threat, especially after a species has already arrived, as it is an outside threat that is extremely hard to control. (HELCOM 2010)

The side effects of eutrophication such as reduced water clarity and increased sedimentation of organic matter have benefited some algal species (primarily filamentous algae) while perennial species such as bladder- wrack (Fucus) have declined. This has caused changes in the invertebrate community (Korpinen and Jormalainen 2008) (HELCOM 2010). In the site, Fucus radicans is also the only endemic species in the region. In addition, cormorants (Phalacrocorax carbo) are benefitting from the euthrophication and are expanding their range north and common bream (Abramis brama) also expanding in range, especially on shallow sea bays (IUCN Consultation, 2020). Other effects caused by eutrophication and overfishing of top predatory species have resulted in an increase in numbers  in Three spined Sticklebacks (Gasterosteus aculeatus) populations, which now threaten other spices such as Pike (Esox Lucius) and Perch. This further straightens the eutrophication effect (Candolin & Voigt, 2020). The risk of this threat is high, based on its widespread occurrence and increasingly negative consequences. As this is a result of the general eutrophication of the Baltic Sea and originates outside the site, the management does not have the capacity or resources to address this threat.

Effects of climate changes are already evident in the Baltic Sea, and global warming is expected to lead to further hydrological changes in the near future. Projected changes include acidification, increased sea level, decreasing ice cover extent, and changed precipitation patterns, leading to altered composition of nutrients, and interactions with other pressures (HELCOM, 2018). Climate related changes should be considered in all aspects of management. Foreseen climate change impacts will be taken into account when updating the HELCOM Baltic Sea Action Plan (HELCOM, 2018).
The apparent uplift rate in the World Heritage site depends on the sea level rise and will most likely change in future. The land uplift maximum is near the city of Umeå, where the current absolute uplift is about 10 mm/year, and during the last century the uplift rate relative to the sea has been almost 9 mm/year (Poutanen, M. et.al., 2014). In addition to the threat posed by climate change to the geological processes’ climate change will further unbalance sea salinity, causing impacts to saline sensitive species and systems, particularly given the low saline concentration to begin with.