YOUR report on the deaths of 10 million salmon last year due to disease and sea lice infestation (A disgrace: 10 million salmon thrown away by fish farms in last year alone, Investigation, October 8) reveals a disaster for fish welfare and the environment. The level of mortality shows that the salmon industry is operating beyond its limits.

But one proposed solution – closed containment systems which separate the salmon from their natural marine environment – comes with major problems for fish welfare of its own.

Taking salmon out of the sea and placing them into large enclosed systems is expensive. To make it profitable, the salmon would have to be kept at high stocking densities, increasing stress and the risk of aggression and injuries such as fin damage, causing suffering to the fish.

We have tried the same thing with land animals, especially pigs and chickens – taking them off the land and putting them into crowded sheds. It is called factory farming, and has led to numerous well-known problems which we should be reluctant to replicate with fish.

The real solution is not to take salmon out of their natural environment, but to manage them better – keeping them in lower numbers to prevent the build-up of parasites and disease. This would benefit the fishes’ welfare and reduce the impact on the environment, as well as reducing the appalling waste shown by your report.

Phil Brooke, Welfare and Education Development Manager, Compassion in World Farming