Perhaps the most farmed group of species on the planet is fish, yet the welfare of these waterborne animals is all too often overlooked.

Here at Compassion, we are gearing up our work on fish welfare to tackle what we see as the burgeoning factory farm industry under the water. I was delighted therefore to interview Dr Lynne Sneddon, Director of Bioveterinary Science at the University of Liverpool, on her groundbreaking work relating to the welfare of fish.

Dr Sneddon’s work focuses on reducing stress and ill health in fish, as well as looking at ways to reduce the number of animals used by replacing them with non-sentient forms.

Her most recent discovery is that young zebrafish, just days old, feel pain and should therefore be protected by European law.

In this interview, we get to the heart of questions, such as whether fish feel pain, how farming practices need to change, and what the future holds for fish welfare?

Philip: What led you to becoming interested in fish as a scientist?

Lynne: Most of the world is covered by water and fish are the most successful vertebrate group on the planet.

Their ability to live in such a wide variety of habitats and under varying environmental conditions is astonishing. Fish can live in deep ocean trenches under enormous pressure but can also be found at high altitude. I believe their ability to evolve and adapt has allowed them to colonise nearly every available aquatic habitat from polar regions to deserts.

However, what I find most interesting is their behaviour: there is nothing that a mammal can do that we cannot find an example of fish being capable of, from parental care through to tool use. Fish are also an important part of the food chain. I believe it is important to study them and safeguard their health and welfare.

Philip: How do you respond to someone who says fish aren’t sentient?

Lynne: Fish can evaluate the actions of others in relation to themselves and third parties. Rabbitfishes form close associations where they forage in pairs. They closely match each other’s behaviour. Whilst one feeds, the other is vigilant, keeping watch for predators and taking turns allowing each other time to forage. Grouper fish form relationships with another species, the moray eel, and they hunt together. Manta rays recognise themselves in mirrors.

Learning and memory research demonstrates that fish can navigate complicated mazes, have numerical skills and can remember for prolonged periods. There are a plethora of scientific studies showing fish can assess risks and benefits, have the potential to experience positive and negative affective states and have some degree of consciousness. These higher order behaviours were thought only to exist in mammals and birds. But now we know fish fulfil the criteria for sentience.

Philip: What do you think about how fish are raised intensively for food?

Lynne: Whilst there have been advances in improving the welfare of farmed fish, I do believe more needs to be done. We still require information on optimal stocking density which should be investigated on a species by species basis since some fish are gregarious whereas others are territorial or aggressive. Environmental enrichment has received little attention for fish, but has been successfully adopted for terrestrial animals.

Fascinated by Fish – why their welfare matters