Salmon farming - use of acoustic deterrent devices: report

6. Ethical Analysis and Critical Issues

Three ethical frameworks were used to assess different aspects of this problem and are discussed below.

Ethical matrix

Ethical matrices are used to assess multiple principles across multiple actors and are particularly used to deal with complex and sometimes conflicting situations in food production. The matrix that was used set out the positive and negative outcomes of the use of ADDs in general with respect to the principles of 'welfare', 'flourishing', 'freedom' and 'fairness' for the species involved (farmed fishes, seals, harbour porpoises, killer whales and minke whales). This approach allows a greater consideration of the more intangible elements of an animal's quality of life that cannot easily be understood from the scientific data. A summary is shown in Table 2.

This approach suggests that there are potential negative impacts on seals and at least four species of cetacean across 2-3 dimensions, while the fish receive positive impacts in three dimensions. At first sight this suggests that there is a greater potential impact on the cetaceans as a group than on the other species.

Consideration of magnitude and severity

However, while this ethical matrix approach allows us a better appreciation of the different dimensions where ADD deployment has positive and negative effects, it does not capture the severity and duration of harms, nor the number of animals affected. Animal welfare pertains to the experience of the individual animal. It is SAWC's opinion that the welfare needs of all sentient animals should be considered. Fishes are considered sentient animals. The numbers of fish affected by seal attacks is far greater than the number of seals and cetaceans affected. Mortality is an outcome for the fishes attacked by seals, and cetaceans forced out of their home ranges by ADD deployment, but mortality rates are far higher in the fish. The severity of other injuries is also arguably higher in the fish, as we are comparing bites to the body of the fish compared with hearing loss in seals and cetaceans, although both types of injury may be fatal or contribute to poor viability. Stress may affect all species. If we applied a 'weighting' system, which accounted for numbers of animals involved and the severity of the negative welfare effects, it would appear that the positive impacts of ADD use are greater for the fish than the negative impacts for the seals or cetaceans.

Application of the Seven Principles for Ethical Wildlife Management to seal control

There is a third ethical element to consider in this context, and that is the role of humans. The farmed fish have been placed into the habitat of the wild seals and cetaceans by fish farmers, who are providing food for the wider human population, and this placement has caused the conflict between the welfare interests of the wild animals and the farmed animals.

The international consensus principles for ethical wildlife control²⁰ were developed as a means of applying ethical and evidence-based approaches to human-wildlife conflicts, and these principles may be helpful in this context. These ethical principles apply to the control of seals around fish farms, where there is a clear conflict between human management of fish populations, fish welfare, and seal welfare. The first principle and second principles suggest modifying human practices and justification for control are the initial approaches to resolving conflict. In the context of fish farming, and particularly the impact on fish welfare of seal attacks and presence, some method of minimising the impacts of seal predation on fish welfare is justified. However, we suggest also that research and technological developments to improve barrier methods to deter seals and reduce the impact of deterrent methods used (such as ADDs) should also be investigated and would be encouraged under the application of the Seven Principles. The third principle addresses the need for clear and achievable outcome-based objectives. This implies that the need for using ADDs must be based on evidence for a negative impact of seal behaviour on fish welfare, and that monitoring of the efficacy and outcomes of the use of ADDs on predation are implemented to justify continued use. The fourth principle of animal welfare has been partly addressed above, but continued research into the welfare impacts of use of ADDs, and methods to minimise these are still required. The remaining principles require consideration of the social acceptability of the use of ADDs (for example in the communities, which might be impacted by their use), requirements for systematic planning to avoid the continued need for the use of ADDs and to minimise conflict with seals in the future and focusing management attention on the specific situation on each site rather than employing a blanket approach to seal management.

Section summary

The greatest impact on welfare lies with the fish, given that seal attacks can result in serious injury and death. Large numbers of fish are also affected. However, given that it is humans that place the fish into the natural habitat of wild seals and cetaceans, it is incumbent on humans to place significant effort into finding viable options to safeguard the welfare of these wild animals, whilst still protecting the welfare of the fish.