How does the UK's National Health Service (NHS) group fish for dietary advice regarding oily fish?

Listing salmon, mackerel, trout, sardines, and herring together as good sources of omega-3s

From a broad public health perspective, official dietary guidance often prioritizes consistent consumption of beneficial food groups over emphasizing minor differences between specific items within that group. The UK's National Health Service (NHS) exemplifies this approach by advising two portions of fish weekly, with one being oily fish. This recommendation groups several types of healthy fish together, specifically listing salmon, mackerel, trout, sardines, and herring as equally valid and good sources of the essential omega-3 fatty acids. This grouping implies that ensuring regular intake of any of these fatty fish is the primary public health goal.