$7 a can? How large? Imo eating ordinary sardines at about $1 a can might be a more sensible idea. Most salmon is safe enough though, especially if one is eating under a pound a week total. Sometimes there is inexpensive salmon available. I don't mind paying a bit more for extra quality, however I avoid $7 small cans of fish.

One could diversify the type and brands of fish they eat if they are worried that a specific batch might be higher in mercury. While some batches do test higher than others, with low mercury fish such as salmon or sardines, even if a batch has double the average level of mercury, the total amount of mercury in a small can is still quite small. One needs to be reasonable about this, and not be too fearful. Salmon or sardines has around 1/20 th the level of mercury that tuna has. Mercury tends to concentrate in larger and older saltwater fish that eat plenty of other fish, such as tuna, swordfish, bass, etc. Sardines tend to have a very short life span. Salmon are freshwater, and also have a very limited lifespan.