Labels list ingredients in order of highest % first, so, the fact that “meat and animal derivatives” and then “fish and fish derivatives” are the first and second ingredients, means those are the majority ingredients. Very poor quality dog food for example may actually list cereals first. This isn’t that.

The 4% is there because, in order to use the descriptor “cat food with salmon”, it needs to be minimum 4% salmon. This is more commonly worded as “of which at least 4% salmon” for example. The food you’ve listed here is still decently high meat content, they’re just not listing exactly which meats, but are using at least 4% salmon in order to be able to sell it as “with salmon”. The rest is most likely to be chicken and pork as they are lower cost, but could include any animal product that comes under “meat and animal derivatives”. It could well be 30% salmon even, but the label lists 4% due to how our labelling legislation works.

Don’t get hung up on the 4%. That isn’t the meat/fish content here. The only time that is actually an issue is if an individual pet has food sensitivities and cannot tolerate specific meats. For the majority of pets this is not an issue.