Science of salmon stocking: report

5. Cost / Benefit analysis

To estimate the cost and benefit of a supplementation programme is a task that, although it should be attempted, may, in practice, be difficult to perform. The capital costs of running the programme can relatively easily be defined, however, the various other associated costs and especially benefits, may be both difficult to accurately measure and be, to a degree, subjective (Table 2).

Table 2

Factors to be included for consideration when performing a cost/benefit analysis.

Costs: Capital

• Positive: Injection of money into local economy
• Negative: May be significant with no guarantee of success

Costs: Operational

• Positive: Injection of money into local economy, jobs
• Negative: Ongoing uncertainties about long term funds

Costs: Broodstock

• Positive: Increase survival of offspring
• Negative: Loss of wild spawning

Costs: Ecological

• Positive: Restore natural fish numbers
• Negative: Competition, pathogens, resources

Costs: Genetic

• Positive: Conservation of genotypes
• Negative: Inbreeding, outbreeding, loss of population size

Costs: Fitness

• Positive: Conservation of phenotypes
• Negative: Loss of fitness of hatchery and wild fish

Costs: Conservation

• Positive: Production, conservation, restoration
• Negative: Displacement of effort

Costs: Economic

• Positive: Fishery, ancillary industries
• Negative: Displacement of effort

Costs: Sociological

• Positive: Appearance, community, history
• Negative: Expectations

It should also be noted that, even if all stakeholders have the same conservation, restoration and/or enhancement aims (which may not always be the case), different conclusions may still be drawn from the same available cost/benefit information and, in turn, this may lead to conflicts with sometimes long‐lasting and disruptive social and political effects (Harrison et al., 2019b). Examples of such divergent conclusions can be found with most hatchery supplementation operations and are well illustrated in Scotland, where managers have come to differing conclusions as to the efficacy of hatchery programmes in geographically and ecologically similar rivers, with, for example, the River Spey deciding to "fully embrace its hatchery operation" (Spey Fishery Board, 2019) despite evidence of marginal if any benefit to the fishery (Coulson et al., 2013), whereas the River Dee concluded that "stocking of the Dee is not appropriate" (McDermott et al., 2016).

Hatchery supplementation raises strong positions on both sides of the debate and this was recently well illustrated during the review and subsequent prohibition of stocking in Wales (Natural Resources Wales, 2014). Strong and entrenched divisions were seen on the pro- and anti-hatchery sides of the discussion, with an often lesser-heard compromise grouping being less vocal. The antagonistic groups disagreed on the effectiveness of stocking, the status of the salmon stock, had different management goals, and the debate was characterised by complex, intertwined and partly opposing beliefs and values (Harrison et al., 2019b). The outcome of the consultation process was a prohibition on stocking in Wales (apart from some limited research) and, hence, a win/lose scenario for the different factions and an associated entrenchment of divisions.

In order to avoid, or at least mitigate, such antagonism, it is vital that the validity of different beliefs, values, objectives and goals are recognised during any cost/benefit evaluation (Redpath et al., 2013). Decision-making should be collaborative (Harrison et al., 2019b), where different stakeholder groups, including scientists and managers, work together to obtain evidence that is mutually accepted (Fujitani et al., 2017; Harrison et al., 2018a). Regulatory bodies can also assist in such a process by developing regulations that, where possible, avoid the necessity to enact a binary choice to either leave open or terminate stocking programs and where alternative approaches which achieve multiple and shared collaborative objectives, may be possible (Harrison et al., 2019b). Thus, when evaluating the cost/benefit of any programme or regulatory framework, it is vital that collaborative strategies are developed that allow competing stakeholder groups to work toward shared realities and achieve multiple objectives (Harrison et al., 2018b) to mitigate or avoid future conflicts (Harrison et al., 2019b).