There is a long history of conflict in Scotland between harbour Phoca vitulina and grey Halichoerus grypus seals, and fisheries for Atlantic salmon Salmo salar. Seals prey on fish migrating through rivers and estuaries and around coastal netting stations, potentially having an indirect negative economic impact on fisheries by reducing numbers available for capture. They also have a direct negative impact by interfering with angling activity in rivers and by damaging coastal nets (Butler et al., 2011a). In turn, salmon fishery operators have legally shot large numbers of seals at coastal haul out sites, having a direct negative impact on some local populations (Thompson et al., 2007) and marine wildlife tourism interests (Butler et al., 2008). A key feature of this conflict is the contestation of stakeholders’ and scientists’ perceptions of the impacts of the species on each other, and potential solutions to the problem. Many fisheries stakeholders believe that seals have major deleterious effects on salmon fisheries and that population control is therefore justified (e.g. Scottish Salmon Strategy Task Force, 1997), while science suggests that at the salmon population level, seal predation is unlikely to have a significant impact relative to other causes of mortality (Middlemas, Armstrong & Thompson, 2003).
This conflict can be framed using the concept of ecosystem services, which are defined as the benefits that people obtain from functioning ecosystems [Millennium Ecosystem Assessment (MA), 2005]. The identification of ecosystem services and their beneficiaries can illuminate the relative costs and benefits of alternative natural resource management strategies (Butler et al., 2011b). Applying the MA (2005) categories for ecosystem services, populations of seals can be regarded as providing ‘cultural’ services to wildlife tourists, tourism operators and the wider public for their recreational and intrinsic conservation values (Fig. 1). Salmon provide ‘provisioning’ services when harvested by coastal netting stations for food provided to consumers, and ‘cultural’ services to anglers, angling guides (‘ghillies’), rod fishery owners and the public for their recreational and conservation value (Butler et al., 2009). These services can be seen as being traded off against each other (Fig. 1). Simplistically, larger seal populations may increase the supply of the services they provide, but at the expense of salmon populations and their services. Conversely, to protect salmon and the services they provide, fishery operators may reduce seal numbers through shooting.
In this conflict, it is scientists’ role to objectively understand the interactions between seals and salmon, hence clarifying the extent of the perceived trade-offs between their services, and to develop and test potential technical innovations that can achieve ‘win-win’ outcomes, represented by the shaded area in Fig. 1. The Moray Firth Seal Management Plan (MFSMP) is the first attempt in Scotland to explore some of the potential alternative strategies to the traditional ‘either-or’ approach of managing seals and salmon based on current scientific knowledge (Butler et al., 2008). Driven by a need to meet new European Union Habitats Directive conservation objectives for both harbour seals and salmon in the Moray Firth, concerns about the impact of shooting on harbour seals by fishery managers, and seal predation of depleted spring-running salmon stocks, the scheme was introduced in 2005 as a pilot for future national policy. Its central basis is an annual license issued by the Scottish Government for fishery managers to shoot a limited number of harbour and grey seals, calculated from seal censuses and the Potential Biological Removal technique (Wade, 1998), within agreed Management Areas that avoid seal pupping sites and concentrations of wildlife tourism. These areas were delineated within and around river mouths, where, in contrast to the wider population, any seals present were most likely to be preying on salmon and were therefore ‘rogue’ animals, and targeted shooting of these animals at appropriate times of the year would protect more vulnerable salmon stocks (Butler et al., 2006).
The findings of Graham et al. (2011) support this principle, particularly for grey seals. As part of the Seal and Salmon Research Programme (SSRP) established within the MFSMP, the photo-identification and digestive tract analysis of seals in the lower reaches of three Moray Firth rivers provides the first evidence that such ‘rogue’ animals exist, and the relative importance of salmonids in their diet. As such, the MFSMP strategy of targeting these animals provides the closest yet to achieving a ‘win-win’ for ecosystem services provided by seals and salmon in this region, although the shooting of some animals still represents a minor negative impact (Fig. 1). By comparison, a ban on shooting seals could have favoured seals to the detriment of salmon, while the continuation of extensive and indiscriminate seal shooting practiced prior to the MFSMP would have further depleted the harbour and grey seal populations, with possible benefits for salmon fisheries (Fig. 1). The next scientific advance would be to develop and implement effective non-lethal methods of keeping ‘rogue’ seals away from rivers and netting stations. This was also an objective of the SSRP, and Graham et al. (2009) have demonstrated the effectiveness of new acoustic deterrent technology elsewhere, although its cost-effectiveness as a tool in the Moray Firth has not yet been determined (Butler et al., 2011a).
However, the perceptions of salmon ecosystem service beneficiaries remain a significant obstacle to achieving this next step in the MFSMP. In 2006, a survey of rod fishery owners, ghillies, anglers and netsmen in the Moray Firth found that 81% believed that seals had a significant or moderate negative impact on stocks and catches, 77% believed that all seals were responsible, and 47% supported seal culling (Butler et al., 2011a). Only 33% believed that individual ‘rogue’ seals were responsible for any impacts, and 6% supported the use of non-lethal methods of controlling seal impacts. These perceptions are at odds with the results of Graham et al. (2011), and the principles of the MFSMP. Furthermore, they reflect those held by other marine fishery interests in Scotland, and are likely therefore to be typical of other areas where the Scottish government aims to implement the MFSMP model through the Marine (Scotland) Act (2010) (Butler et al., 2011a).
Because the scheme involves the top-down government assessment of seal populations and subsequent issuing of licences, fishery stakeholder support is not a necessity for the system to function. However, there is ample evidence from the adaptive co-management literature to show that sustained outcomes are more likely to emerge from initiatives such as the MFSMP if stakeholders’ multiple knowledge systems are mutually respected and integrated, thus promoting conflict resolution, learning, genuine power-sharing and social-ecological system resilience (Armitage et al., 2009). This presents a challenge for the manner in which future research into seal and salmon interactions and potential solutions is conducted, and how the results are disseminated to stakeholders. The more usual mode of undertaking ecological science in such situations is to maintain objectivity by excluding stakeholders’ direct input, which can subsequently undermine their trust in the research results (Young et al., 2010). Instead, scientists may have to modify their approach to include stakeholders as co-researchers, as often practiced with indigenous communities where knowledge contestation is also common (e.g. Gratani et al., 2011).
An important target for inclusion in the Moray Firth would be those stakeholders that bear the direct economic costs of seal predation, namely the fishery owners in the lower reaches of rivers and Management Areas, and netsmen (Butler et al., 2011a). It will also be important to establish informal institutions that promote the sharing of knowledge and the stimulation of social learning among all stakeholders, and these will have to be adequately resourced to enable regular and well-attended meetings. Without a more inclusive approach, the knowledge divide between science, salmon fishery and seal stakeholders will not be bridged, and the development and implementation of innovative strategies that can simultaneously maintain ecosystem services provided by both seals and salmon may remain unattainable.