Client: Department for Environment, Food, and Rural Affairs (Defra)

Year: 2024

eftec team: Tiziana Papa, Russell Drummond, Ian Dickie, Claudio Contento, Emma Thomas

Partners: University of Glasgow

Link to full report: Click here

Industrial activities on the sea and the seabed put pressure on marine mammals, ranging from acoustic trauma to habitat degradation. However, there is still a critical lack of evidence which hampers the development of effective policies.

The need to fill this gap is urgent given the UK’s increasingly complex marine agenda, which must balance economic priorities (such as achieving net-zero energy and sustainable fisheries) with environmental goals including global biodiversity commitments and domestic nature recovery targets.

This study was commissioned by Defra to address this need: to gain a better understanding of the effects of marine activities on mammal species and ecosystems over short and long timescales and gather evidence on the related costs and benefits, with a view for this to be integrated in the economic appraisal of marine policies.

Results

The project has created a framework to link scientific and economic evidence, suggesting values of tens to hundreds of millions of pounds per year for different effects on the abundance and distribution of marine mammal populations. These values are significant in relation to the scale of marine economic activities and, if used in impact assessments, could support measures to avoid or mitigate such effects.

Method: Designing the Framework

eftec partnered with University of Glasgow to combine our scientific, policy, and economic expertise. The framework we created followed the logic chain below.

We first reviewed scientific evidence to investigate the effect of pressures from selected marine activities on the groups of marine mammals in scope: accounting for the extent, intensity, and location of these activities. This helped determine total expected ecological effect on marine mammals. Examples can be seen in the table below.

The economic evidence review values included the use values (such as ecosystem services, tourism and recreation) and non-use values (such as the cultural importance of a species’ existence) associated with marine mammals. The assumption is that negative impacts on marine mammals would lead to loss of these values. Since only tourism has an actual market, we reviewed a range non-market valuation studies. The evidence from these studies is then applied to novel contexts in the framework using value transfer.

Example: Offshore Windfarms

The figure below provides an example of how the evidence framework can be applied to an offshore wind farm:

• The marine activity is the construction of an offshore windfarm

• The extent of resulting pressures in the marine environment such as noise, collision, and contamination can be estimated

• Using scientific evidence, we can quantify the effects on bottlenose dolphin populations and the outcomes of these impacts (such as the change in population)

• Using economic evidence, such as the cultural values for the existence of bottlenose dolphins and the use value from sightseeing, we can quantify the costs (or benefits) of the change in population

• This enables us to quantify the overall change in economic welfare as a result of the effects to bottlenose dolphins due to the creation of a windfarm

In this example, we estimated a value in the range of £246 million to £499 million per year for the effects of offshore wind construction on the abundance of whales, dolphins, and seals in the UK. The level of confidence is moderate as there is a good match between valuation studies and impacts, but available data still produces a broad range.

Limitations & Recommendations for Future Work

Due to the complex nature of marine environments and the relative lack of data on their condition, the existing evidence is not complete and findings in the report do not cover all effects on marine mammals. The gaps are significant, such as a lack of data on the abundance, distribution, behaviour, and connectedness of marine mammal populations (particularly in remote or deep-sea habitats and during winter months). These gaps should always be stated when they are used in economic appraisal.

Furthermore, there is scientific evidence that multiple pressures can have significant cumulative effects on marine mammals, resulting in non-marginal (large) and non-linear (exponential) effects: for example, by crossing thresholds over which population survival is severely compromised. However, economic appraisal still assumes marginal (small, incremental) changes that have linear effects on populations. Therefore, while still useful, the existing economic evidence risks underestimating the effects.

This work represents an important first step in integrating projected effects on marine mammal populations into decision-making. We also point to where future research efforts should be directed: such as data collection through citizen science and new technologies, as well as the development of models that can account for the cumulative effects of multiple human activities and other environmental stressors on marine mammal populations.

Link to full report: Click here