3 Review of the Impacts Associated with Marine Litter
There are numerous problems and threats caused directly or indirectly by marine litter, including environmental, social and economic impacts. These impacts are diverse, usually interconnected thus are harder to mitigate separately. Despite this our overall understanding of these issues is limited in some areas, particularly the indirect and socio-economic effects (Mouat et al., 2010). An example of this, are the differing impacts of ghost fishing, resulting in economic losses to commercial and recreational fisheries as well persistent and cumulative environmental impacts (Macfadyen et al., 2009).
Marine litter threatens the realisation of a shared vision for 'clean, healthy, safe, productive, biologically diverse marine and coastal environments, managed to meet the long term needs of nature and people'. The general implications for the Scottish economy are also widespread, such as beach cleaning, loss of tourism and the impacts of the fishing industry (damaged gear, lost commercial catches). Most noticeably, marine litter poses a considerable threat to the health and productivity of marine ecosystems. As such, the presence of marine litter in our seas may also impact upon Scotland's Strategic Objectives, most notably the drive to become a Greener, Wealthier & Fairer, Safer & Stronger and Healthier Scotland.
3.1 Environmental Impacts
As a result of the presence of marine litter there are a wide variety of short and long term adverse environmental impacts to individual organisms, species and ecosystems as a whole. Marine litter can damage benthic environments, cause a loss of biodiversity and lead to a reduction in overall ecosystem function (Moore, 2008; Derraik, 2002; Ten Brink, 2009).
The entanglement by and ingestion of, marine litter by organisms, are the most noticeable short-term impacts (Gregory, 2009; Thompson et al., 2009). It is estimated that 267 species are affected by marine litter globally of which 86% of all sea turtle species, 44% of seabird species, 43% of marine mammal species are affected (Laist, 1997; U.S. Commission on Ocean Policy, 2004; Allsopp et al., 2006).Plastic litter in particular, is estimated to lead to the mortality either directly or indirectly of one million seabirds, 100,000 marine mammals (including 30,000 seals) and 100,000 turtles globally every year; either through entanglement or ingestion (Wallace, 1985; Laist, 1997; Moore, 2008).
Secondary long-term impacts are usually associated with the fate and interaction of in-situ debris over a long period of time. Ecosystem deterioration can result from a combination of these impacts, such as habitat damage (physical damage, fishing gear), reduced population size (bio-accumulation of toxins, increased competition from invasives, higher mortality rates) and biodiversity loss (Mouat et al., 2010).
Ingestion is one of the main impacts on marine wildlife. It is estimated that 177 marine species have ingested litter items which include whole plastic bags, gallon drums and balloons, mistakenly identified as food by mammal, turtle and shark species (Laist, 1997; MCS, 2009). Resin pellets, convenience food packaging and plastic bags are among some of the litter ingested by birds, marine mammals and sea turtles which are particularly susceptible to floating plastic bags, mistaking them for jellyfish (U.S. Commission on Ocean Policy, 2004).
The ingestion of marine litter is well documented, with extensive literature and numerous international case studies (Gregory 1978, 1991; 2009; Mato et al. 2001; Oehlmann et al. 2009; Teuten et al. 2009; van Franeker et al, 2005; Laist, 1997).
The main physical problems, as a result of litter ingestion, being:
- wounds (internal and external);
- blockage of oesophagus and damage to the digestive tract leading to internal infections, satiation, debilitation, drowning, and starvation;
- impaired reproductive capacity;
- reduced predator avoidance;
- impaired feeding capacity and malnutrition
Specifically, ingested plastic resin pellets can absorb and concentrate toxic compounds from surrounding seawater, inside marine mammals, fish and vertebrates, becoming potentially toxic. Organisms are at increased risk of diseases, altered hormone levels and death as a result of ingestion (Derraik, 2002; Gregory, 2009; OSPAR, 2009).
There are various accounts of marine debris ingestion by a variety of seabirds over the last 50 years (Laist, 1997; Gregory, 2009). It is estimated at least 111 of the world's 312 species of seabird are known to have accidentally eaten plastic (Laist, 1997; Allsopp et al., 2006). Surface and plankton feeders (albatrosses, shearwaters, petrels, gulls, auklets and puffins), are the most susceptible seabirds to litter ingestion, due to their feeding patterns. Plastic pellets and pieces are often mistaken by seabirds for food such as fish eggs and plankton, and are thus fed to chicks (Day et al., 1985).
Since 1979, research on the stomach contents of dead fulmars in the North Sea has been undertaken (Van Franeker et al., 2008; OSPAR, 2010). An Ecological Quality Objective (EcoQo) to quantify plastic in seabird stomachs, has been developed from this research by OSPAR and is used to identify the extent of floating litter at sea ( OSPAR, 2010) and has become a model for the implementation of the Marine Strategy Framework Directive.
Specifically the EcoQo states "There should be less than 10% of Northern Fulmars (Fulmarus glacialis) having 0.1 gram or more plastic in the stomach in samples of 50-100 beach washed fulmars from each of 5 different regions of the North Sea over a period of at least 5 years" (Van Franeker et al., 2008; OSPAR, 2010).
During the period 2003-2006 over 1000 beached fulmars were examined, with 45-60% having more than 0.1g of plastic in their stomachs (figure 3-1). The Scottish Islands were comparatively uncontaminated, with fulmar stomachs containing only a third of marine debris encountered by fulmars in the Channel area. However despite this, 50% of beach-washed fulmars on the Scottish Islands still breached the EcoQo level (Van Franeker et al., 2008).
Figure 3 ‑ 1 The EcoQO performance of Fulmars from study areas around the North Sea over the 5 year period 2002 - 2006: the percentage of beached Fulmars having more than 0.1g plastic in the stomach (adapted from OSPAR, 2010)
Specific marine litter items such as plastic bags suspended in the water column can resemble prey and thus have a greater probability of ingestion and impact (Bugoni et al., 2001; Balazs, 1985; Tomas et al., 2002). This can often impact upon turtle species, which are becoming increasingly common in UK waters (Figure 3-3). For example the stomach contents of a Leatherback turtle ( Dermochelys coriacea) found in Galloway, contained seven different types of plastic bag ( MCS, 2009).
Figure 3 ‑ 2 Distribution (sightings & strandings) of turtle species in UK coastal waters 1999-2009 (Taken from Penrose & Gander, 2010)
Ingestion has been reported to have caused the death or injury of Cuvier's Beaked whale, Minke whale and grey seals in UK waters. Many such species are BAP species or protected Nature Conservation (Scotland) Act 2004 and the Habitats and Species Directives for example.
The impacts of marine litter on lower trophic levels influence population size and prey availability having greater implications for higher trophic levels and the stability of the food web. For example small plastic pieces can enter the food web through their ingestion by filter feeders, deposit feeders and detritivores, possibly leading to bio-accumulation in their predators and higher trophic levels (Thompson et al., 2004; Browne et al., 2008). However relatively little data is available on the specific impacts on lower trophic levels and further research is needed.
Entanglement by items such as fishing nets and line, lures, light sticks, crab/lobster/fish traps, plastic bags, strapping bands and four/six pack yokes pose a significant risk to marine organisms ( MCS, 2009; Ten Brink, 2009). These items are responsible for an estimated 62% of all entanglements and can reduce movement, cause injury and in some cases death from starvation, drowning or suffocation ( MCS, 2009; Ocean Conservancy, 2009).
An estimated 136 species of marine vertebrate and eight invertebrate species have been reported entangled in marine litter including six turtle species, 11 cetacean species, 19 pinniped species, 51 seabird species and 34 fish species (Laist, 1997; Ten Brink, 2009).
The main physical problems, as a result of litter entanglement, being (Derraik 2002; Gregory 2009; Mouat et al., 2010):
- wounds (external) which can cause infection, ulceration and death;
- asphyxiation (fish- require motion for respiration);
- reduced fitness due to increased energy costs of travel;
- impaired reproductive capacity;
- reduced predator avoidance due to impaired mobility;
- impaired feeding capacity and malnutrition;
- restricted growth and reduced circulation to limbs
It is estimated up to 100,000 marine mammals per year die as a result of entanglement in lost fishing gear and other marine debris (Moore, 2008; Wallace, 1985). Although the risk of death caused by entanglement is greater than ingestion, quantifying mortality rates is difficult as a large proportion of casualties are consumed by predators or sink to the seafloor, with only beached animals recorded (Laist & Liffmann, 2000; Derraik, 2002; MCS, 2009).
Entanglement along with other ecological impacts of marine litter can hinder conservation efforts, accounting for a high proportion of mortality rates in endangered species.
3.1.3 Ghost fishing
Until the 1950's rope and cordage were made from natural fibres (Indian, Manila hemp and cotton), which quickly disintegrated in-situ when discarded and lost; posing only a short-term risk to marine organisms (Gregory, 2009). Natural fibres have since been replaced by synthetic materials due to their durability and cost effectiveness. As a result they pose a greater long-term risk when discarded creating a phenomena known as 'ghost fishing'.
Ghost fishing occurs when discarded or lost fishing gear (nets, ropes, traps) continue to catch and kill fish and marine animals in-situ, particularly if the nets are intact ( MCS, 2009; UNEP, 2009). This can cause a loss to commercial catches and impact protected species populations ( UNEP, 2009).
Net losses have been shown to be generally less than 1 %; the overall length of net lost annually is 209 km for European fisheries. An exception to this is the deepwater fisheries for Monkfish in the North east Atlantic where it has been shown over 25,000 nets are lost each year with an overall length of 1254 km (Brown and Macfayden, 2007).
The efficiency of ghost fishing is dependant on the type fishing gear and local environmental conditions; most notably the degree of exposure and wave conditions and the bottom substrate, with rocky areas tangling nets within a much shorter time frame than muddy or sandy sediments. The nets themselves are likely to remain intact in the environment for some time due to their synthetic construction, yet it has been shown in an European wide study ( FANTARED) the catching capacity of the nets is often limited to a few weeks due to deterioration in net structure and the weighting and closing of the nets by their initial catches (Pawson, 2003).
Since ghost fishing is inherently indiscriminate, a diverse range of species are affected, including seabirds, seals, cetaceans and commercially important fish species (Macfadyen et al., 2009). As with general entanglement there is increasing concern of the overall impact on vulnerable or endangered species (Allsopp et al., 2006; Sheavly &Register, 2007). It is estimated that 130,000 cetaceans are killed globally each year by ghost fishing (Ten Brink, 2009).
Commercial fisheries are affected by reduced recruitment and reduction in reproductive potential, caused by the capture of immature fish by ghost fishing (Williams et al., 2005; Macfadyen et al., 2009), although this impact is thought to be small compared to direct catches. The Committee on the Effectiveness of International and National Measures to Prevent and Reduce Marine Debris and Its Impacts (2008) estimate that ghost fishing accounts for < 5% of commercial EU landings for gillnet and tangle net fisheries and <1.5% of commercial monkfish landings (Brown et al., 2005). In the case of smaller stocks however, ghost fishing may be cause for concern, especially for those of conservation concern.
3.1.4 Secondary pollutants
The increased fragmentation of in-situ plastic litter items, can lead to the production of micro-plastics and chemicals (Thompson et al., 2009). Micro-plastics also enter the oceans, from commercial activities (cleansing and air blasting) where they are used as 'scrubbers' (Derraik 2002; Thompson et al 2009).
Micro-plastics and associated chemicals are transferred to the aquatic food web and up trophic levels, from their ingestion by marine species such as mussels and pose a significant threat to a wider range of organisms due to their size (Thompson et al., 2004; Barnes et al 2009).
In addition, micro-plastics concentrate organic pollutants such as PCBs, DDE and nonylphenols (Barnes et al., 2009; Moore, 2008). This enables these pollutants to enter living organisms and food webs (Committee on the Effectiveness of International and National Measures to Prevent and Reduce Marine Debris and Its Impacts et al 2008; DEFRA 2011).
The full biological effects of associated pollutants are currently unknown (Thompson et al., 2009). Indeed the overall uptake of micro-plastics and full environmental implications are unknown but their abundance has increased and will continue to, due to their longevity in the marine environment (Thompson et al., 2009; Thompson et al 2004).
3.1.5 Introduced species
The proliferation of marine litter particularly plastics provide additional opportunities for the dispersal of non-native, potentially invasive species (Lewis et al., 2005; Gregory 2009). The type and size of debris can influence colonisation patterns and biota (Moret-Ferguson et al., 2010).
It is estimated marine litter has doubled or tripled dispersal opportunities for marine organisms (Allsopp et al., 2006). Although dispersal routes are passive, dependent upon ocean currents, they contribute to increased frequency of travel and allow non-native species to adapt to local climatic conditions due to the slow rate of travel. Thus they can be more effective a vector than ship hulls and ballast water (Moore, 2008).
The most common biota attached to marine litter are barnacles, bryozoans and polychaete worms (Allsopp et al., 2006). The increasing northward distribution of a number of species for example the large barnacle ( Perforatus perforatus) and the Australasian barnacle ( Austrominius modestus), has been attributed to marine litter as a vector (Rees & Southward, 2008; Moore, 2008). Climate is often a limiting factor with many introduced and potentially invasive species; however their range may extend northwards towards Scotland with a warming climate (Hiscock et al., 2004).
Invasive non-native species have been shown to out compete native species and inadvertently cause biodiversity loss, changes to trophic and habitat structure and ecosystem functions (Derraik 2002; Donnan 2009). Due to these devastating environmental effects, invasive species are recognised as one the greatest threats to global biodiversity (Barnes and Milner 2005). The economic impact of such species can be substantial.
3.1.6 Benthic Habitats
Physical damage to benthic habitats can include abrasion, scouring, breaking and smothering (Sheavly & Register, 2007). The smothering of benthic organisms on the seafloor is due to reduced oxygen in sediments caused by litter, which prevents gas exchange between overlying waters. This can lead to changes in the composition of biota on the seafloor (Derraik, 2002). A great deal of marine litter is likely to accumulate on the seafloor, yet despite this the long-term threat to benthic organisms and habitats is relatively unknown.
3.1.7 Ecosystem deterioration
The long-term impacts of marine litter through combined pressures such as entanglement, ingestion, damage to benthic environments and loss of biodiversity, on ecosystem deterioration are relatively uncertain (Hyrenbach and Kennish, 2008). Despite a lack of research into the impact of marine litter on ecosystem services, it is highly likely that litter reduces the resilience of ecosystems, and hence the quality of ecosystem services they provide.
The pressures of marine litter add to other anthropological stressors in the marine environment, such as over-fishing, coastal development, ocean acidification and pollution events (Derraik, 2002).This amalgamation of environmental stressors may combine to cause ecosystem deterioration (either in the short or long term) and reduce ecosystem resilience to withstand large perturbations in the environment, such as climate change ( ICC, 2009).
3.2 Social Impacts
Marine litter causes social impacts such as direct short-term public health issues (injuries, entanglement and navigational hazards) and indirect, long-term impacts on quality of life (recreational opportunities, loss of aesthetic value and loss of non-use value). There is limited data on the overall influence marine litter has on society, and further research is needed (Cheshire et al., 2009; Mouat et al., 2010).
3.2.1 Public Health Issues
Marine litter can pose significant risks to human health and is considered a public health issue, both as beached litter or circulating in coastal waters (Fanshawe & Everard, 2002; Sheavly & Register, 2007). Beached marine litter such as broken glass, medical waste, fishing line, and discarded syringes can harm beach users as well as the risks associated with the leaching of poisonous chemicals (Rees & Pond, 1994; Sheavly & Register, 2007; Thompson et al., 2009). In the UK, between 1988 and 1991, 4% of injuries by needles reported to the Public Health Laboratory Service in the Southwest of England were sustained on the beach (Phillip, 1993; Fanshawe & Everard, 2002).
Sewage related debris is particularly harmful and is considered a potential biohazard and may act as a vector for viruses and bacteria (Rees & Pond, 1994). More indirect effects come in the form of wider social impacts, influencing UK coastal tourism and the local economy as a result.
Establishing the frequency and overall extent of incidents, is difficult as most incidents are unrecorded (Laist & Liffmann, 2000; Sheavly, 2005).
3.2.2 Sewage Related Debris
One of the main sources of SRD is from combined sewage overflows and constitutes sanitary products such as nappies, baby wipes, condoms, tampon applicators and needles (Sheavly & Register, 2007). Over one and a half billion sanitary items are deposited in UK toilets per year (Defra, 2005b). In 2003, Scottish Water reported 340 million items in Scotland flushed a year at a cost of £16 million (Scottish Water 2003).
SRD may present serious water quality concerns as with the presence of these items there is increased risk of bacterial (e.g. E. coli) and viral contamination of surrounding coastal waters. Indeed consumption of or contact with contaminated water can pose a risk of contracting hepatitis, cholera, typhoid, diarrhoea, bacillary dysentery and skin rashes (Defra, 2005b; Williams et al., 2005). These problems have resulted in expensive closures of beaches in the US.
3.2.3 Human entanglement
Entanglement can also pose a serious threat to recreational users, particularly for swimmers, snorkelers and SCUBA divers who can become entangled in submerged or floating debris, such as fishing nets and ropes. According to the British Sub-Aqua Club, approximately one or two entanglement incidents occur each year in the UK and are potentially life-threatening, usually involving monofilament netting (Fanshawe & Everard, 2002; Mouat et al., 2010).
3.2.4 Navigational hazards: Non-military
Marine litter poses navigational hazards to all kinds of vessels (submarines, passenger ferries, fishing vessels) and can result in serious consequences, including loss of life (Allsopp et al., 2006; Chivers & Drew 2005; Macfadyen et al., 2009). However evidence of incidents endangering vessels' safety is usually anecdotal with the majority of incidents unreported, thus the overall impact and risk is difficult to evaluate.
The main risks to navigation from marine litter (particularly during poor weather conditions) include:
- fouling and entanglement of a vessel's propeller in derelict fishing gear: reducing stability and the ability to manoeuvre;
- blockage of water intakes by plastic bags;
- subsurface debris can foul anchors and equipment deployed from trawlers and research vessels;
- collisions can damage a vessel's propeller shaft seal;
- recovery procedures which require divers increases risk of personal injury (Sheavly & Register, 2007; Macfadyen et al., 2009; Mouat et al., 2010).
3.2.5 Navigational hazards: Military
In addition to normal navigational hazards by pleasure craft and commercial enterprise, the same risks also apply to military activities which are active in the marine, submarine and inter-littoral zones. Marine litter can disturb the physical environment, affecting the ability to detect certain phenomena many of which are important to the UK's defence capability. These include surface and submarine navigation and geo-acoustics (Fanshawe & Everard, 2002).
3.2.6 Threats to fishermen
Threats to fishermen can include the snagging of fishing gear on marine litter, increasing the risk of capsize, and in some circumstances resulting in loss of life. Objects caught in nets and brought aboard can also contain toxic substances or disposed of munitions (Edwards, 1995; Olin et al., 1995).
Remediation and preventative measures include the deployment of surveillance aircraft to identify the location of lost objects; the notification to mariners of the location of floating or sunken containers, cargo or debris; the emergency towing of floating containers; and the transfer of cargo from a stricken vessel, all of which are dependent on the availability of financial resources (Fanshawe & Everard, 2002).
The transfer of litter between the land and sea can also be reversed where beached marine litter is windblown back ashore, affecting coastal communities. This has been shown to damage to property and equipment including stock fencing where the litter accumulation prevents wind movement through the fencing and will ultimately flatten effected fencing. Other impacts include harm to livestock through ingestion and entanglement and the resulting economic impact to the land owner/farmer.
In the Shetland Islands, 96% of crofters reported marine litter on their land, including plastic, rope, strapping bands and nets (Mouat, 2010).
3.2.8 Coastal industries
Marine litter has been shown to impact upon industry such as coastal power stations via blockages in intake pipes (Fanshawe & Everard, 2002). Thus screening is required along with automated clearance mechanisms and manual labour to clear blockages. Regular clearances are necessary thus contributing to overall running costs.
3.2.9 Flood defence
Litter clearance is also necessary for coastal defences. Drains and weirs need to be cleared and protected in order to efficiently divert waters away from vulnerable flood zones (Fanshawe & Everard, 2002). The high cost of cleaning and potential damage as a result of defence failures, heightens the overall impact marine litter has on society.
3.2.10 Recreational activities
The marine and coastal zones offer the opportunity for many social and recreational activities such as swimming, diving, boating, and recreational fishing. The accumulation of marine litter can act as a strong but subjective deterrent from these activities (Ballance et al., 2000; Sheavly & Register 2005).
Ballance et al., (2000) and ENCAMS (2005) showed the majority of beach users rank cleanliness as a priority in their choice of destination, with 97% avoiding beaches with more than 10 large litter items per metre. Other recreational users such as divers are deterred by the accumulation of marine litter due to the loss of visual amenity and greater health and safety risks (Sheavly & Register, 2007; Cheshire et al., 2009). More research is required to determine the overall affects marine litter has on recreational use.
Studies for Scotland have shown that 99% of Scottish beach visitors rated litter free sand as the most important thing they wanted to see at beaches they visited. (Dow, 2004) and another focussed on Scottish Community Councils who responded to a survey highlighting that the greatest perceived problem to the beaches in their area was marine and coastal litter. Erosion and sewage pollution were also seen as problems (Clean Coast Scotland, 2002).
3.2.11 Aesthetic and non-use value
Marine litter can devalue the visual amenity of the coastal and marine landscape, influencing the tourism sector; recreational activities; the inspirational quality of the marine environment, which is frequently the focus of many of the creative arts; and ultimately the local economy and quality of life for coastal communities (Cheshire et al., 2009; Naturvårdsverket 2009).
The mere knowledge that an ecosystem exists and is maintained is of value in itself. Marine litter deprecates the following non-use values (existence, bequest and altruistic):
- the knowledge of the existence of a desirable coastal and marine environment;
- the ability to bequest unimpaired resources to future generations;
- the altruistic benefits of preservation for other users;
- the inherent belief that a litter-free marine environment is intrinsically desirable
(Committee on the Effectiveness of International and National Measures to Prevent and Reduce Marine Debris and Its Impacts et al., 2008).
3.3 Economic Impact of Marine Litter
Marine litter has a substantial direct and indirect impact upon the Scottish and UK economy. For several years policy makers and communities have experienced the problem of marine litter on beaches, waterways, bays and ports and the subsequent impacts on a range of economic activities. Marine litter is a serious non-point source pollution problem that is pervasive , and impacts users of the marine in several ways. Of these, the direct impacts are the most obvious, from local authorities responsible for clean-up activities, the loss of tourism expenditure or shifts in tourism activity, and the loss of vessel activity as a result of propeller fouling or bringing up litter in fishing nets. Indirect impacts can also be substantial and occur from a decline in the environmental quality of the coast that can cause losses in amenity and resulting losses in property values, opportunity costs and civic pride. Despite the uncertainties, marine litter also impacts upon ecosystem services. While economic costing of ecosystem services is considered a relatively new science, it is clear that marine and coastal litter can impact and deteriorate a range of natural functions that provide on-going social and economic benefits.
The full economic cost of the impact of marine litter on the environment is complex because some impacts are more readily evaluated than others. For example costs for cleaning operations or lost fishing revenue from entanglement are captured in traditional economic calculations but the economic implications of degraded ecosystem services are difficult to value (Mouat et al. 2010).
3.3.2 Total Economic Value
The concept of total economic value ( TEV) (figure 3-3) is one of several approaches used in exploring the evaluation of the environment and is being used in research programs such as the UK National Ecosystem Assessment and the Crown Estate guidelines on valuing the marine environment (Saunders et al 2010). Ecosystem goods and services contribute to human wellbeing in several ways and individuals and communities place a value on these resources depending on their values and the social context. What the TEV framework does is explore the impacts on overall 'wellbeing' and classifies different types of economic value, including monetisation where possible. Direct use valuation is the most common approach and where most of the effort of valuation occurs. It classifies usage according to direct interaction with the ecosystem. It is split into consumptive uses such as fishing or extractive activities and non-consumptive uses that use ecosystems to confer benefits without extracting resources e.g. recreation and tourism. Indirect use refers to economic benefits derived from an ecosystem but do not relate to spatial interaction. This could be the broader societal benefits from nutrient cycling or waste management, or from socio-economic activities such as education, science, or culture. Option values refer to the potential for future uses of an ecosystem, or viewed as another way, an insurance policy for future societal activities. Non-use values are centred on societal interest in the 'existence' of natural systems and benefits that does not correlate with direct or indirect use of a resource. While important, they are difficult to quantify in direct monetary terms but can be captured by other approaches such as contingent valuation methods. Non-use values raise important ethical questions about sustainability and inter and intra generational equity concerning ecosystems. The Crown Estate (Saunders et al 2010) notes that while TEV is a tool to aid in decision-making, it does not aim to provide all of the answers about the valuation of ecosystem services - monetary valuation is not feasible for every type of resource or service.
Figure 3 ‑ 3 Total Economic Value Framework
3.3.3 The value of UK and Scottish Maritime Industries
For the UK as a whole the marine environment is economically important, supporting a diverse range of activities including marine resource extraction, tourism and commercial shipping. The value of the UK maritime economy was valued by the Crown Estate in 2008 at £46 billion pounds (Pugh 2008). In 2005-06 direct marine related activities comprised 4.2% of UK GDP and approximately 890,000 jobs. The total of the direct and indirect contribution to GDP was approximately 6.2-6.9%. At the Scottish scale, the seas continue this trend of an important and valuable economic and social commodity. The 'Sustainable Seas for All' consultation (Scottish Government 2008) identified that the Scottish maritime economy contributed a minimum of £ 2.2 billion per annum supporting approximately 50 000 jobs (not including oil and gas extraction). Key sectors include oil and gas activities incidental to extraction (£1.12 billion per annum); fisheries, aquaculture and processing (£1.1 billion); ship and boat building (£300 million); and marine transport (£101 million). Recent assessments have been made for emerging sectors such as marine and coastal tourism and recreational fishing. Scottish Government (2010) identified that marine wildlife tourism has a net economic impact of £15 million, with 633 additional FTE jobs and coastal wildlife tourism has a net economic impact of £24 million with 995 additional FTE jobs. Sea angling was valued by the Scottish Government (2009) at £70 million per annum and supporting 3148 full time job equivalents. Marine litter has the capacity to affect all of the above sectors by impacting direct and indirect activity.
As noted in Ten Brink (2009) the costs associated with marine litter are often borne by parties different from those causing the problem. The result is that there is insufficient liability to the entities responsible for the marine litter problem, and a lack of incentives to reduce littering practice. Expressed differently - the polluter, whether it is industries or individuals, does not pay. This is compounded by lack of enforcement mechanisms and actions. Adding to this complexity is the fact that marine litter comes from a diverse array of sources - from land and sea, from individuals, communities, and industries across a variety of spatial scales. The resolution of these problems requires considerable policy innovation and the use of a portfolio of traditional command and control instruments, market based instruments and education and awareness raising initiatives. Indeed, the marine litter problem can be construed within the frame of a 'wicked problem' as defined by Jentoft (2008) where no clear technical solution can be found to a problem that crosses scales and interests. Addressing the problem of marine litter therefore requires investment in long term social change and policy innovation across jurisdictions.
3.3.4 Towards Understanding the Total Economic Impact on Marine Litter
Data on the economic impacts of marine litter in Scotland is sparse. Ten Brink et al (2009) reiterated that the understanding of the economic significance of marine litter remains relatively limited and this is particularly relevant at the Scottish scale. From Figure 3-4 below, the approximate economic cost of the marine litter problem in Scotland is £16.8 million per annum. However, this figure is underestimated - the economic costs are likely to be much higher as many sectors do not have data on impacts, and there is no research on the economic impacts of indirect, option, and non-use values (Figure 3-3). There is a need to further improve data collection across a range of sectors to gauge the direct and indirect economic costs.
Figure 3 ‑ 4 Impact of marine litter on maritime sectors
The implications for the Scottish economy are highly significant, from the cost of cleaning beaches, loss of tourism revenue, and the economic cost of direct impacts of damaged gear or lost commercial catches in fisheries. The most recent research on the economic impacts of marine litter was conducted by KIMO (Moat et al 2010) at the scale of the NE Atlantic, with a breakdown of the data to the UK scale and in some instances the Scottish scale. The KIMO method used a sector-based approach to investigate the increased costs and potential loss of revenue associated with marine litter for key industries. This report draws upon many of the KIMO figures to adapt to the Scottish scale.
Using the total economic value framework and the figures from the literature, a picture emerges of the considerable impacts of the litter problem. In the category of direct and consumptive use, fisheries sustained considerable economic impacts of £10 million pounds per annum in Scotland (Mout et al 2010). Aquaculture had considerably less impacts from litter at £133 562 per annum. Data on impacts upon other extractive sectors such as oil and gas, Scottish agriculture and recreational angling was non-existent. Mouat et al (2010) identified costs of £841 per croft per annum in the Shetlands and a total cost to agriculture in the Shetlands of £217 000 per annum. Further research on impacts across small scale and large scale agriculture Scotland is required to assess the true costs of marine litter.
A wide range of industries operate that utilise marine space and provide a variety of services. Marine litter imposes, at a minimum, a £6 million per annum economic impact on non-consumptive users. This is particularly problematic for local authorities who are responsible for cleaning litter off beaches for visitors and residents. From the KIMO study, an average figure of €145 586 per UK municipality was obtained; converting this to UK currency and multiplying across the 24 coastal authorities in Scotland results in clean-up costs of over £3 000 000 per annum. While the costs per municipality are inherently variable, this gives an indicative figure of the extent of the problem.
For the tourism industry, recreational sailing and the emerging renewables industry there is a lack of data on the impacts caused by marine litter. In the case of tourism, a critically important industry for coastal regions, marine litter may cause deterioration in the quality of the location, the experience of the visitor and may change the preference of location. The study by Ballance et al (2000) found that 85% of tourists and residents would not visit a beach with more than 2 debris items per metre and 97% would not go to a beach with 10 or more large items of litter per metre. This could lead to a shift in the geography of tourism, and impact the 'brand' of tourism industries. For example, the Scottish Government has recognised the importance of developing the wildlife and ecotourism sector (Scottish Government 2010). Marine litter can compromise the 'clean and green' image that is important for the sector and for tourism in general. The level of litter to deter tourists from visiting certain areas is a subjective issue depending on personal preference, the activity and litter levels in surrounding regions. As highlighted in Balance et al (2000) and Mout et al (2010) there is a pressing need to advance research on the perceptions and interactions between tourists and coastal litter and at what level litter will shift tourism away from a particular site.
In terms of indirect use, the picture on impacts is unclear. The challenge is to identify the range of services implied by indirect use than calculate the benefits and estimate the costs. Volunteering is one area that could be considered an indirect use of a coastal system as volunteers and groups offer services based on respect and for local environmental amenity. Data is emerging for the impacts of marine litter on volunteering. Mout et al (2010) conducted a survey that calculated that in recent Marine Conservation Society and Keep Scotland Beautiful beach cleaning campaigns, 8809 volunteers contributed £112 906 to removing beach litter. While one interpretation of this impact is a 'cost' to volunteer time, it could also be considered a positive impact to improving social capital and coastal awareness. Visual amenity is another indirect impact of marine litter and could affect property prices in coastal areas as well as impact tourism and a range of non-use values such as publicity and civic pride. Aesthetic costs occur when the presence of marine litter in an area affects the public's perception about the quality of the surrounding marine environment, water quality and amenities. This negative perception potentially impacts the value of local property and the quality of life of residents.
3.3.5 Ecosystem impacts
Emerging research in the UK is exploring the value of ecosystem goods and services but the impact of marine litter upon these values is at this point in time unclear. This report concurs with Ten Brink et al (2009) and Moat et al (2010) that we do not have a complete picture of the magnitude of impacts associated with the incidence of marine litter, particularly in relation to the impacts upon ecosystem services and resilience. Resilience is an important concept that relates to the ability of natural systems to maintain structure and function in the face of environmental change. Marine litter is an additional pressure in a stressed marine and coastal environment that is facing cumulative pressures from climate change, pollution, development and extraction of biological resources.
As described above through the TEV framework, the coastal systems provide many valuable services and these can be packaged in different ways as 'benefits'. However uncertainty often exists due to the variability of ecosystem functioning at different scales and the links between ecosystem functions, services and flows of benefits. Generally speaking, ecosystem services such supporting, provisioning, regulating or cultural services offer a benefit if there is a direct or indirect human gain - some of which can be quantified by economic transactions or qualitative assessments (Figure 3-5).
While there is limited data on the impact of marine litter on ecosystem processes (Figure 3-5) it is clear from this study that there are significant impacts upon ecosystem services and benefits for society. While our understanding of impacts is improving in regards to direct economic activities, when it comes to a broader array of ecological services such as waste assimilation or pollution control, our understanding is limited in terms of the process itself and the economic impact. While a total economic figure may be elusive at this time, it is clear that litter will negatively affect a range of primary processes, final ecosystem services and the resulting goods and benefits for people.
Figure 3 ‑ 5 The interaction of litter with ecosystem services and benefits. Adapted from NE (2010)
It is clear that marine litter undermines a range of ecosystems processes and benefits and that there are clear gaps in the evidence base in capturing the impacts upon total economic value (Figure 3-6). Under the direct use domain, gaps remain across individual sectors such as oil and gas, agriculture, angling, and parts of the tourism and recreational industries. Further research is needed to gauge the preferences of visitors towards areas that are impacted by litter and the extent of the shifting of tourism activity. Indirect uses including ecosystem service benefits, option values and non-use 'existence' values that relate to cultural wellbeing can be quantified, but this is a relatively new field of research and no data is currently available at the Scottish scale. This paper endorses further evidence gathering to assess the impacts of marine litter across all areas of total economic value to inform a future strategy.
Figure 3 ‑ 6 Status of data for assessing the impacts of marine litter on total economic value